DRY-FARMING

A SYSTEM OF AGRICULTURE FOR COUNTRIES UNDER LOW RAINFALL

BY JOHN A. WIDTSOE, A. M. , Ph. D

PRESIDENT OF THE AGRICULTURAL COLLEGE OF UTAH

NEW YORK

1920

TO

LEAH

THIS BOOK IS INSCRIBED

JUNE 1, 1910

PREFACE

Nearly six tenths of the earth's land surface receive an annualrainfall of less than twenty inches, and can be reclaimed foragricultural purposes only by irrigation and dry-farming. Aperfected world-system of irrigation will convert about one tenth ofthis vast area into an incomparably fruitful garden, leaving aboutone half of the earth's land surface to be reclaimed, if at all, bythe methods of dry-farming. The noble system of modern agriculturehas been constructed almost wholly in countries of abundantrainfall, and its applications are those demanded for theagricultural development of humid regions. Until recently irrigationwas given scant attention, and dry-farming, with its world problemof conquering one half of the earth, was not considered. These factsfurnish the apology for the writing of this book. 

One volume, only, in this world of many books, and that less than ayear old, is devoted to the exposition of the accepted dry-farmpractices of to-day. 

The book now offered is the first attempt to assemble and organizethe known facts of science in their relation to the production ofplants, without irrigation, in regions of limited rainfall. Theneeds of the actual farmer, who must understand the principlesbefore his practices can be wholly satisfactory, have been kept inview primarily; but it is hoped that the enlarging group of dry-farminvestigators will also be helped by this presentation of theprinciples of dry-farming. The subject is now growing so rapidlythat there will soon be room for two classes of treatment: one forthe farmer, and one for the technical student. 

This book has been written far from large libraries, and thematerial has been drawn from the available sources. Specificreferences are not given in the text, but the names of investigatorsor institutions are found with nearly all statements of fact. Thefiles of the Experiment Station Record and Der Jahresbericht derAgrikultur Chemie have taken the place of the more desirableoriginal publications. Free use has been made of the publications ofthe experiment stations and the United States Department ofAgriculture. Inspiration and suggestions have been sought and foundconstantly in the works of the princes of American soilinvestigation, Hilgard of California and King of Wisconsin. I amunder deep obligation, for assistance rendered, to numerous friendsin all parts of the country, especially to Professor L. A. Merrill, with whom I have collaborated for many years in the study of thepossibilities of dry-farming in Western America. 

The possibilities of dry-farming are stupendous. In the strength ofyouth we may have felt envious of the great ones of old; of Columbuslooking upon the shadow of the greatest continent; of Balboashouting greetings to the resting Pacific; of Father Escalante, pondering upon the mystery of the world, alone, near the shores ofAmerica's Dead Sea. We need harbor no such envyings, for in theconquest of the nonirrigated and nonirrigable desert are offered asfine opportunities as the world has known to the makers and shakersof empires. We stand before an undiscovered land; through therestless, ascending currents of heated desert air the vision comesand goes. With striving eyes the desert is seen covered withblossoming fields, with churches and homes and schools, and, in thedistance, with the vision is heard the laughter of happy children. 

The desert will be conquered. 

JOHN A. WIDTSOE. 

June 1, 1910. 

CHAPTER I

INTRODUCTION

DRY-FARMING DEFINED

Dry-farming, as at present understood, is the profitable productionof useful crops, without irrigation, on lands that receive annuallya rainfall of 20 inches or less. In districts of torrential rains, high winds, unfavorable distribution of the rainfall, or otherwater-dissipating factors, the term "dry-farming" is also properlyapplied to farming without irrigation under an annual precipitationof 25 or even 30 inches. There is no sharp demarcation betweendry-and humid-farming. 

When the annual precipitation is under 20 inches, the methods ofdry-farming are usually indispensable. When it is over 30 inches, the methods of humid-farming are employed; in places where theannual precipitation is between 20 and 30 inches, the methods to beused depend chiefly on local conditions affecting the conservationof soil moisture. Dry-farming, however, always implies farming undera comparatively small annual rainfall. 

The term "dry-farming" is, of course, a misnomer. In reality it isfarming under drier conditions than those prevailing in thecountries in which scientific agriculture originated. Manysuggestions for a better name have been made. "Scientificagriculture" has-been proposed, but all agriculture should bescientific, and agriculture without irrigation in an arid countryhas no right to lay sole claim to so general a title. "Dry-landagriculture, " which has also been suggested, is no improvement over"dry-farming, " as it is longer and also carries with it the idea ofdryness. Instead of the name "dry-farming" it would, perhaps, bebetter to use the names, "arid-farming. " "semiarid-farming, ""humid-farming, " and "irrigation-farming, " according to the climaticconditions prevailing in various parts of the world. However, at thepresent time the name "dry-farming" is in such general use that itwould seem unwise to suggest any change. It should be used with thedistinct understanding that as far as the word "dry" is concerned itis a misnomer. When the two words are hyphenated, however, acompound technical term--"dry-farming"--is secured which has ameaning of its own, such as we have just defined it to be; and"dry-farming, " therefore, becomes an addition to the lexicon. 

Dry-versus humid-farming

Dry-farming, as a distinct branch of agriculture, has for itspurpose the reclamation, for the use of man, of the vast unirrigable"desert" or "semi-desert" areas of the world, which until recentlywere considered hopelessly barren. The great underlying principlesof agriculture are the same the world over, yet the emphasis to beplaced on the different agricultural theories and practices must beshifted in accordance with regional conditions. The agriculturalproblem of first importance in humid regions is the maintenance ofsoil fertility; and since modern agriculture was developed almostwholly under humid conditions, the system of scientific agriculturehas for its central idea the maintenance of soil fertility. In aridregions, on the other hand, the conservation of the natural waterprecipitation for crop production is the important problem; and anew system of agriculture must therefore be constructed, on thebasis of the old principles, but with the conservation of thenatural precipitation as the central idea. The system of dry-farmingmust marshal and organize all the established facts of science forthe better utilization, in plant growth, of a limited rainfall. Theexcellent teachings of humid agriculture respecting the maintenanceof soil fertility will be of high value in the development ofdry-farming, and the firm establishment of right methods ofconserving and using the natural precipitation will undoubtedly havea beneficial effect upon the practice of humid agriculture. 

The problems of dry-farming

The dry-farmer, at the outset, should know with comparative accuracythe annual rainfall over the area that he intends to cultivate. Hemust also have a good acquaintance with the nature of the soil, notonly as regards its plant-food content, but as to its power toreceive and retain the water from rain and snow. In fact, aknowledge of the soil is indispensable in successful dry-farming. Only by such knowledge of the rainfall and the soil is he able toadapt the principles outlined in this volume to his special needs. 

Since, under dry-farm conditions, water is the limiting factor ofproduction, the primary problem of dry-farming is the most effectivestorage in the soil of the natural precipitation. Only the water, safely stored in the soil within reach of the roots, can be used incrop production. Of nearly equal importance is the problem ofkeeping the water in the soil until it is needed by plants. Duringthe growing season, water may be lost from the soil by downwarddrainage or by evaporation from the surface. It becomes necessary, therefore, to determine under what conditions the naturalprecipitation stored in the soil moves downward and by what meanssurface evaporation may be prevented or regulated. The soil-water, of real use to plants, is that taken up by the roots and finallyevaporated from the leaves. A large part of the water stored in thesoil is thus used. The methods whereby this direct draft of plantson the soil-moisture may be regulated are, naturally, of the utmostimportance to the dry-farmer, and they constitute another vitalproblem of the science of dry-farming. 

The relation of crops to the prevailing conditions of arid landsoffers another group of important dry-farm problems. Some plants usemuch less water than others. Some attain maturity quickly, and inthat way become desirable for dry-farming. Still other crops, grownunder humid conditions, may easily be adapted to dry-farmingconditions, if the correct methods are employed, and in a fewseasons may be made valuable dry-farm crops. The individualcharacteristics of each crop should be known as they relatethemselves to a low rainfall and arid soils. 

After a crop has been chosen, skill and knowledge are needed in theproper seeding, tillage, and harvesting of the crop. Failuresfrequently result from the want of adapting the crop treatment toarid conditions. 

After the crop has been gathered and stored, its proper use isanother problem for the dry-farmer. The composition of dry-farmcrops is different from that of crops grown with an abundance ofwater. Usually, dry-farm crops are much more nutritious andtherefore should command a higher price in the markets, or should befed to stock in corresponding proportions and combinations. 

The fundamental problems of dry-farming are, then, the storage inthe soil of a small annual rainfall; the retention in the soil ofthe moisture until it is needed by plants; the prevention of thedirect evaporation of soil-moisture during; the growing season; theregulation of the amount of water drawn from the soil by plants; thechoice of crops suitable for growth under arid conditions; theapplication of suitable crop treatments, and the disposal ofdry-farm products, based upon the superior composition of plantsgrown with small amounts of water. Around these fundamental problemscluster a host of minor, though also important, problems. When themethods of dry-farming are understood and practiced, the practice isalways successful; but it requires more intelligence, more implicitobedience to nature's laws, and greater vigilance, than farming incountries of abundant rainfall. 

The chapters that follow will deal almost wholly with the problemsabove outlined as they present themselves in the construction of arational system of farming without irrigation in countries oflimited rainfall. 

CHAPTER II

THE THEORETICAL BASIS OF DRY-FARMING

The confidence with which scientific investigators, familiar withthe arid regions, have attacked the problems of dry-farming restslargely on the known relationship of the water requirements ofplants to the natural precipitation of rain and snow. It is a mostelementary fact of plant physiology that no plant can live and growunless it has at its disposal a sufficient amount of water. 

The water used by plants is almost entirely taken from the soil bythe minute root-hairs radiating from the roots. The water thus takeninto the plants is passed upward through the stem to the leaves, where it is finally evaporated. There is, therefore, a more or lessconstant stream of water passing through the plant from the roots tothe leaves. 

By various methods it is possible to measure the water thus takenfrom the soil. While this process of taking water from the soil isgoing on within the plant, a certain amount of soil-moisture is alsolost by direct evaporation from the soil surface. In dry-farmsections, soil-moisture is lost only by these two methods; forwherever the rainfall is sufficient to cause drainage from deepsoils, humid conditions prevail. 

Water for one pound dry matter

Many experiments have been conducted to determine the amount ofwater used in the production of one pound of dry plant substance. Generally, the method of the experiments has been to grow plants inlarge pots containing weighed quantities of soil. As needed, weighedamounts of water were added to the pots. To determine the loss ofwater, the pots were weighed at regular intervals of three days toone week. At harvest time, the weight of dry matter was carefullydetermined for each pot. Since the water lost by the pots was alsoknown, the pounds of water used for the production of every pound ofdry matter were readily calculated. 

The first reliable experiments of the kind were undertaken underhumid conditions in Germany and other European countries. From themass of results, some have been selected and presented in thefollowing table. The work was done by the famous Germaninvestigators, Wollny, Hellriegel, and Sorauer, in the earlyeighties of the last century. In every case, the numbers in thetable represent the number of pounds of water used for theproduction of one pound of ripened dry substance:

Pounds Of Water For One Pound Of Dry Matter

 Wollny Hellreigel SorauerWheat 338 459Oats 665 376 569Barley 310 431Rye 774 353 236Corn 233Buckwheat 646 363Peas 416 273Horsebeans 282Red clover 310Sunflowers 490Millet 447

It is clear from the above results, obtained in Germany, that theamount of water required to produce a pound of dry matter is not thesame for all plants, nor is it the same under all conditions for thesame plant. In fact, as will be shown in a later chapter, the waterrequirements of any crop depend upon numerous factors, more or lesscontrollable. The range of the above German results is from 233 to774 pounds, with an average of about 419 pounds of water for eachpound of dry matter produced. 

During the late eighties and early nineties, King conductedexperiments similar to the earlier German experiments, to determinethe water requirements of crops under Wisconsin conditions. Asummary of the results of these extensive and carefully conductedexperiments is as follows:--

Oats 385Barley 464Corn 271Peas 477Clover 576Potatoes 385

The figures in the above table, averaging about 446 pounds, indicatethat very nearly the same quantity of water is required for theproduction of crops in Wisconsin as in Germany. The Wisconsinresults tend to be somewhat higher than those obtained in Europe, but the difference is small. 

It is a settled principle of science, as will be more fullydiscussed later, that the amount of water evaporated from the soiland transpired by plant leaves increases materially with an increasein the average temperature during the growing season, and is muchhigher under a clear sky and in districts where the atmosphere isdry. Wherever dry-farming is likely to be practiced, a moderatelyhigh temperature, a cloudless sky, and a dry atmosphere are theprevailing conditions. It appeared probable therefore, that in aridcountries the amount of water required for the production of onepound of dry matter would be higher than in the humid regions ofGermany and Wisconsin. To secure information on this subject, Widtsoe and Merrill undertook, in 1900, a series of experiments inUtah, which were conducted upon the plan of the earlierexperimenters. An average statement of the results of six years'experimentation is given in the subjoined table, showing the numberof pounds of water required for one pound of dry matter on fertilesoils:--

Wheat 1048Corn 589Peas 1118Sugar Beets 630

These Utah findings support strongly the doctrine that the amount ofwater required for the production of each pound of dry matter isvery much larger under arid conditions, as in Utah, than under humidconditions, as in Germany or Wisconsin. It must be observed, however, that in all of these experiments the plants were suppliedwith water in a somewhat wasteful manner; that is, they were givenan abundance of water, and used the largest quantity possible underthe prevailing conditions. No attempt of any kind was made toeconomize water. The results, therefore, represent maximum resultsand can be safely used as such. Moreover, the methods ofdry-farming, involving the storage of water in deep soils andsystematic cultivation, were not employed. The experiments, both inEurope and America, rather represent irrigated conditions. There aregood reasons for believing that in Germany, Wisconsin, and Utah theamounts above given can be materially reduced by the employment ofproper cultural methods. 

The water in the large bottle would be required to produce the grainin the small bottle. 

In view of these findings concerning the water requirements ofcrops, it cannot be far from the truth to say that, under averagecultural conditions, approximately 750 pounds of water are requiredin an arid district for the production of one pound of dry matter. Where the aridity is intense, this figure may be somewhat low, andin localities of sub-humid conditions, it will undoubtedly be toohigh. As a maximum average, however, for districts interested indry-farming, it can be used with safety. 

Crop-producing power of rainfall

If this conclusion, that not more than 750 pounds of water arerequired under ordinary dry-farm conditions for the production ofone pound of dry matter, be accepted, certain interestingcalculations can be made respecting the possibilities ofdry-farming. For example, the production of one bushel of wheat willrequire 60 times 750, or 45, 000 pounds of water. The wheat kernels, however, cannot be produced without a certain amount of straw, whichunder conditions of dry-farming seldom forms quite one half of theweight of the whole plant. Let us say, however, that the weights ofstraw and kernels are equal. Then, to produce one bushel of wheat, with the corresponding quantity of straw, would require 2 times45, 000, or 90, 000 pounds of water. This is equal to 45 tons of waterfor each bushel of wheat. While this is a large figure, yet, in manylocalities, it is undoubtedly well within the truth. In comparisonwith the amounts of water that fall upon the land as rain, it doesnot seem extraordinarily large. 

One inch of water over one acre of land weighs approximately 226, 875pounds. Or over 113 tons. If this quantity of water could be storedin the soil and used wholly for plant production, it would produce, at the rate of 45 tons of water for each bushel, about 2-1/2 bushelsof wheat. With 10 inches of rainfall, which up to the present seemsto be the lower limit of successful dry-farming, there is a maximumpossibility of producing 25 bushels of wheat annually. 

In the subjoined table, constructed on the basis of the discussionof this chapter, the wheat-producing powers of various degrees ofannual precipitation are shown:--

One acre inch of water will produce 2-1/2 bushels of wheat. 

Ten acre inches of water will produce 25 bushels of wheat. 

Fifteen acre inches of water will produce 37-1/2 bushels of wheat. 

Twenty acre inches of water will produce 50 bushels of wheat. 

It must be distinctly remembered, however, that under no knownsystem of tillage can all the water that falls upon a soil bebrought into the soil and stored there for plant use. Neither is itpossible to treat a soil so that all the stored soil-moisture may beused for plant production. Some moisture, of necessity, willevaporate directly from the soil, and some may be lost in many otherways. Yet, even under a rainfall of 12 inches, if only one half ofthe water can be conserved, which experiments have shown to be veryfeasible, there is a possibility of producing 30 bushels of wheatper acre every other year, which insures an excellent interest onthe money and labor invested in the production of the crop. 

It is on the grounds outlined in this chapter that students of thesubject believe that ultimately large areas of the "desert" may bereclaimed by means of dry-farming. The real question before thedry-farmer is not, "Is the rainfall sufficient?" but rather, "Is itpossible so to conserve and use the rainfall as to make it availablefor the production of profitable crops?"

CHAPTER III

DRY-FARM AREAS--RAINFALL

The annual precipitation of rain and snow determines primarily thelocation of dry-farm areas. As the rainfall varies, the methods ofdry-farming must be varied accordingly. Rainfall, alone, does not, however, furnish a complete index of the crop-producingpossibilities of a country. 

The distribution of the rainfall, the amount of snow, thewater-holding power of the soil, and the variousmoisture-dissipating causes, such as winds, high temperature, abundant sunshine, and low humidity frequently combine to offset thebenefits of a large annual precipitation. Nevertheless, no oneclimatic feature represents, on the average, so correctlydry-farming possibilities as does the annual rainfall. Experiencehas already demonstrated that wherever the annual precipitation isabove 15 inches, there is no need of crop failures, if the soils aresuitable and the methods of dry-farming are correctly employed. Withan annual precipitation of 10 to 15 inches, there need be very fewfailures, if proper cultural precautions are taken. With our presentmethods, the areas that receive less than 10 inches of atmosphericprecipitation per year are not safe for dry-farm purposes. What thefuture will show in the reclamation of these deserts, withoutirrigation, is yet conjectural. 

Arid, semiarid, and sub-humid

Before proceeding to an examination of the areas in the UnitedStates subject to the methods of dry-farming it may be well todefine somewhat more clearly the terms ordinarily used in thedescription of the great territory involved in the discussion. 

The states lying west of the 100th meridian are loosely spoken of asarid, semiarid, or sub-humid states. For commercial purposes nostate wants to be classed as arid and to suffer under the handicapof advertised aridity. The annual rainfall of these states rangesfrom about 3 to over 30 inches. 

In order to arrive at greater definiteness, it may be well to assigndefinite rainfall values to the ordinarily used descriptive terms ofthe region in question. It is proposed, therefore, that districtsreceiving less than 10 inches of atmospheric precipitation annually, be designated arid; those receiving between 10 and 20 inches, semiarid; those receiving between 20 and 30 inches, sub-humid, andthose receiving over 30 inches, humid. It is admitted that even sucha classification is arbitrary, since aridity does not alone dependupon the rainfall, and even under such a classification there is anunavoidable overlapping. However, no one factor so fully representsvarying degrees of aridity as the annual precipitation, and there isa great need for concise definitions of the terms used in describingthe parts of the country that come under dry-farming discussions. Inthis volume, the terms "arid, " "semiarid, " "sub-humid" and "humid"are used as above defined. 

Precipitation over the dry-farm territory

Nearly one half of the United States receives 20 inches or lessrainfall annually; and that when the strip receiving between 20 and30 inches is added, the whole area directly subject to reclamationby irrigation or dry-farming is considerably more than one half (63per cent) of the whole area of the United States. 

Eighteen states are included in this area of low rainfall. The areasof these, as given by the Census of 1900, grouped according to theannual precipitation received, are shown below:--

Arid to Semi-arid GroupTotal Area Land Surface (Sq. Miles)

Arizona 112, 920California 156, 172Colorado 103, 645Idaho 84, 290Nevada 109, 740Utah 82, 190Wyoming 97, 545TOTAL 746, 532

Semiarid to Sub-Humid Group

Montana 145, 310Nebraska 76, 840New Mexico 112, 460North Dakota 70, 195Oregon 94, 560South Dakota 76, 850Washington 66, 880TOTAL 653, 095

Sub-Humid to Humid Group

Kansas 81, 700Minnesota 79, 205Oklahoma 38, 830Texas 262, 290TOTAL 462, 025

GRAND TOTAL 1, 861, 652

The territory directly interested in the development of the methodsof dry-farming forms 63 per cent of the whole of the continentalUnited States, not including Alaska, and covers an area of 1, 861, 652square miles, or 1, 191, 457, 280 acres. If any excuse were needed forthe lively interest taken in the subject of dry-farming, it is amplyfurnished by these figures showing the vast extent of the countryinterested in the reclamation of land by the methods of dry-farming. As will be shown below, nearly every other large country possessessimilar immense areas under limited rainfall. 

Of the one billion, one hundred and ninety-one million, four hundredand fifty-seven thousand, two hundred and eighty acres(1, 191, 457, 280) representing the dry-farm territory of the UnitedStates, about 22 per cent, or a little more than one fifth, issub-humid and receives between 20 and 30 inches of rainfall, annually; 61 per cent, or a little more than three fifths, issemiarid and receives between 10 and 20 inches, annually, and about17 per cent, or a little less than one fifth, is arid and receivesless than 10 inches of rainfall, annually. 

These calculations are based upon the published average rainfallmaps of the United States Weather Bureau. In the far West, andespecially over the so-called "desert" regions, with their sparsepopulation, meteorological stations are not numerous, nor is it easyto secure accurate data from them. It is strongly probable that asmore stations are established, it will be found that the areareceiving less than 10 inches of rainfall annually is considerablysmaller than above estimated. In fact, the United States ReclamationService states that there are only 70, 000, 000 acres of desert-likeland; that is, land which does not naturally support plants suitablefor forage. This area is about one third of the lands which, so faras known, at present receive less than 10 inches of rainfall, oronly about 6 per cent of the total dry-farming territory. 

In any case, the semiarid area is at present most vitally interestedin dry-farming. The sub-humid area need seldom suffer from drouth, if ordinary well-known methods are employed; the arid area, receiving less than 10 inches of rainfall, in all probability, canbe reclaimed without irrigation only by the development of moresuitable. Methods than are known to-day. The semiarid area, which isthe special consideration of present-day dry-farming represents anarea of over 725, 000, 000 acres of land. Moreover, it must beremarked that the full certainty of crops in the sub-humid regionswill come only with the adoption of dry-farming methods; and thatresults already obtained on the edge of the "deserts" lead to thebelief that a large portion of the area receiving less than 10inches of rainfall, annually, will ultimately be reclaimed withoutirrigation. 

Naturally, not the whole of the vast area just discussed could bebrought under cultivation, even under the most favorable conditionsof rainfall. A very large portion of the territory in question ismountainous and often of so rugged a nature that to farm it would bean impossibility. It must not be forgotten, however, that some ofthe best dry-farm lands of the West are found in the small mountainvalleys, which usually are pockets of most fertile soil, under agood supply of rainfall. The foothills of the mountains are almostinvariably excellent dry-farm lands. Newell estimates that195, 000, 000 acres of land in the arid to sub-humid sections arecovered with a more or less dense growth of timber. This timberedarea roughly represents the mountainous and therefore the nonarableportions of land. The same authority estimates that the desert-likelands cover an area of 70, 000, 000 acres. Making the most liberalestimates for mountainous and desert-like lands, at least one halfof the whole area, or about 600, 000, 000 acres, is arable land whichby proper methods may be reclaimed for agricultural purposes. Irrigation when fully developed may reclaim not to exceed 5 per centof this area. From any point of view, therefore, the possibilitiesinvolved in dry-farming in the United States are immense. 

Dry-farm area of the world

Dry-farming is a world problem. Aridity is a condition met and to beovercome upon every continent. McColl estimates that in Australia, which is somewhat larger than the continental United States ofAmerica, only one third of the whole surface receives above 20inches of rainfall annually; one third receives from 10 to 20inches, and one third receives less than lO inches. That is, about1, 267, 000, 000 acres in Australia are subject to reclamation bydry-farming methods. This condition is not far from that whichprevails in the United States, and is representative of everycontinent of the world. The following table gives the proportions ofthe earth's land surface under various degrees of annualprecipitations:--

Annual Precipitation Proportion of Earth's Land SurfaceUnder 10 inches 25. 0 per centFrom 10 to 20 inches 30. 0 per centFrom 20 to 40 inches 20. 0 per centFrom 40 to 60 inches 11. 0 per centFrom 60 to 80 inches 9. 0 per centFrom 100 to 120 inches 4. 0 per centFrom 120 to 160 inches 0. 5 per centAbove 160 inches 0. 5 per centTotal 100 per cent

Fifty-five per cent, or more than one half of the total land surfaceof the earth, receives an annual precipitation of less than 20inches, and must be reclaimed, if at all, by dry-farming. At least10 per cent more receives from 20 to 30 inches under conditions thatmake dry-farming methods necessary. A total of about 65 per cent ofthe earth's land surface is, therefore, directly interested indry-farming. With the future perfected development of irrigationsystems and practices, not more than 10 per cent will be reclaimedby irrigation. Dry-farming is truly a problem to challenge theattention of the race. 

CHAPTER IV

DRY-FARM AREAS. --GENERAL CLIMATIC FEATURES

The dry-farm territory of the United States stretches from thePacific seaboard to the 96th parallel of longitude, and from theCanadian to the Mexican boundary, making a total area of nearly1, 800, 000 square miles. This immense territory is far from being avast level plain. On the extreme east is the Great Plains region ofthe Mississippi Valley which is a comparatively uniform country ofrolling hills, but no mountains. At a point about one third of thewhole distance westward the whole land is lifted skyward by theRocky Mountains, which cross the country from south to northwest. Here are innumerable peaks, canons, high table-lands, roaringtorrents, and quiet mountain valleys. West of the Rockies is thegreat depression known as the Great Basin, which has no outlet tothe ocean. It is essentially a gigantic level lake floor traversedin many directions by mountain ranges that are offshoots from thebackbone of the Rockies. South of the Great Basin are the highplateaus, into which many great chasms are cut, the best known andlargest of which is the great Canon of the Colorado. North and eastof the Great Basin is the Columbia River Basin characterized bybasaltic rolling plains and broken mountain country. To the west, the floor of the Great Basin is lifted up into the region of eternalsnow by the Sierra Nevada Mountains, which north of Nevada are knownas the Cascades. On the west, the Sierra Nevadas slope gently, through intervening valleys and minor mountain ranges, into thePacific Ocean. It would be difficult to imagine a more diversifiedtopography than is possessed by the dry-farm territory of the UnitedStates. 

Uniform climatic conditions are not to be expected over such abroken country. The chief determining factors of climate--latitude, relative distribution of land and water, elevation, prevailingwinds--swing between such large extremes that of necessity theclimatic conditions of different sections are widely divergent. Dry-farming is so intimately related to climate that the typicalclimatic variations must be pointed out. 

The total annual precipitation is directly influenced by the landtopography, especially by the great mountain ranges. On the east ofthe Rocky Mountains is the sub-humid district, which receives from20 to 30 inches of rainfall annually; over the Rockies themselves, semiarid conditions prevail; in the Great Basin, hemmed in by theRockies on the east and the Sierra Nevadas on the west, more aridconditions predominate; to the west, over the Sierras and down tothe seacoast, semiarid to sub-humid conditions are again found. 

Seasonal distribution of rainfall

It is doubtless true that the total annual precipitation is thechief factor in determining the success of dry-farming. However, thedistribution of the rainfall throughout the year is also of greatimportance, and should be known by the farmer. A small rainfall, coming at the most desirable season, will have greatercrop-producing power than a very much larger rainfall poorlydistributed. Moreover, the methods of tillage to be employed wheremost of the precipitation comes in winter must be considerablydifferent from those used where the bulk of the precipitation comesin the summer. The successful dry-farmer must know the averageannual precipitation, and also the average seasonal distribution ofthe rainfall, over the land which he intends to dry-farm before hecan safely choose his cultural methods. 

With reference to the monthly distribution of the precipitation overthe dry-farm territory of the United States, Henry of the UnitedStates Weather Bureau recognizes five distinct types; namely: (1)Pacific, (2) Sub-Pacific, (3) Arizona, (4) the Northern RockyMountain and Eastern Foothills, and (5) the Plains Type:--

_"The Pacific Type. --_This type is found in all of the territorywest of the Cascade and Sierra Nevada ranges, and also obtains in afringe of country to the eastward of the mountain summits. Thedistinguishing characteristic of the Pacific type is a wet season, extending from October to March, and a practically rainless summer, except in northern California and parts of Oregon and Washington. About half of the yearly precipitation comes in the months ofDecember, January, and February, the remaining half beingdistributed throughout the seven months--September, October, November, March, April, May, and June. "

_"Sub-Pacific Type. --_The term 'Sub-Pacific' has been given to thattype of rainfall which obtains over eastern Washington, Nevada, andUtah. The influences that control the precipitation of this regionare much similar to those that prevail west of the Sierra Nevada andCascade ranges. There is not, however, as in the eastern type, asteady diminution in the precipitation with the approach of spring, but rather a culmination in the precipitation. "

_"Arizona Type. --_The Arizona Type, so called because it is morefully developed in that territory than elsewhere, prevails overArizona, New Mexico, and a small portion of eastern Utah and Nevada. This type differs from all others in the fact that about 35 per centof the rain falls in July and August. May and June are generally themonths of least rainfall. "

_"The Northern Rocky Mountain and Eastern Foothills Type. --_Thistype is closely allied to that of the plains to the eastward, andthe bulk of the rain falls in the foothills of the region in Apriland May; in Montana, in May and June. "

_"The Plains Type. --_This type embraces the greater part of theDakotas, Nebraska, Kansas; Oklahoma, the Panhandle of Texas, and allthe great corn and wheat states of the interior valleys. This regionis characterized by a scant winter precipitation over the northernstates and moderately heavy rains during the growing season. The. Bulk of the rains comes in May, June, and July. "

This classification emphasizes the great variation in distributionof rainfall over the dry-farm territory of the country. West of theRocky Mountains the precipitation comes chiefly in winter andspring, leaving the summers rainless; while east of the Rockies, thewinters are somewhat rainless and the precipitation comes chiefly inspring and summer. The Arizona type stands midway between thesetypes. This variation in the distribution of the rainfall requiresthat different methods be employed in storing and conserving therainfall for crop production. The adaptation of cultural methods tothe seasonal distribution of rainfall will be discussed hereafter. 

Snowfall

Closely related to the distribution of the rainfall and the averageannual temperature is the snowfall. Wherever a relatively largewinter precipitation occurs, the dry-farmer is benefited if it comesin the form of snow. The fall-planted seeds are better protected bythe snow; the evaporation is lower and it appears that the soil isimproved by the annual covering of snow. In any case, the methods ofculture are in a measure dependent upon the amount of snowfall andthe length of time that it lies upon the ground. 

Snow falls over most of the dry-farm territory, excepting thelowlands of California, the immediate Pacific coast, and otherdistricts where the average annual temperature is high. The heaviestsnowfall is in the intermountain district, from the west slope ofthe Sierra Nevadas to the east slope of the Rockies. The degree ofsnowfall on the agricultural lands is very variable and dependentupon local conditions. Snow falls upon all the high mountain ranges. 

Temperature

With the exceptions of portions of California, Arizona, and Texasthe average annual surface temperature of the dry-farm territory ofthe United States ranges from 40 deg to 55 deg F. The average is notfar from 45 deg F. This places most of the dry-farm territory in theclass of cold regions, though a small area on the extreme eastborder may be classed as temperate, and parts of California andArizona as warm. The range in temperature from the highest in summerto the lowest in winter is considerable, but not widely differentfrom other similar parts of the United States. The range is greatestin the interior mountainous districts, and lowest along theseacoast. The daily range of the highest and lowest temperatures forany one day is generally higher over dry-farm sections than overhumid districts. In the Plateau regions of the semiarid country theaverage daily variation is from 30 to 35 deg F. , while east of theMississippi it is only about 20 deg F. This greater daily range ischiefly due to the clear skies and scant vegetation which facilitateexcessive warming by day and cooling by night. 

The important temperature question for the dry-farmer is whether thegrowing season is sufficiently warm and long to permit the maturingof crops. There are few places, even at high altitudes in the regionconsidered, where the summer temperature is so low as to retard thegrowth of plants. Likewise, the first and last killing frosts areordinarily so far apart as to allow an ample growing season. It mustbe remembered that frosts are governed very largely by localtopographic features, and must be known from a local point of view. It is a general law that frosts are more likely to occur in valleysthan on hillsides, owing to the downward drainage of the cooled air. Further, the danger of frost increases with the altitude. Ingeneral, the last killing frost in spring over the dry-farmterritory varies from March 15 to May 29, and the first killingfrost in autumn from September 15 to November 15. These limitspermit of the maturing of all ordinary farm crops, especially thegrain crops. 

Relative humidity

At a definite temperature, the atmosphere can hold only a certainamount of water vapor. When the air can hold no more, it is said tobe saturated. When it is not saturated, the amount of water vaporactually held by the air is expressed in percentages of the quantityrequired for saturation. A relative humidity of 100 per cent meansthat the air is saturated; of 50 per cent, that it is only one halfsaturated. The drier the air is, the more rapidly does the waterevaporate into it. To the dry-farmer, therefore, the relativehumidity or degree of dryness of the air is of very greatimportance. According to Professor Henry, the chief characteristicsof the geographic distribution of relative humidity in the UnitedStates are as follows:--

(1) Along the coasts there is a belt of high humidity at allseasons, the percentage of saturation ranging from 75 to 80 percent. 

(2) Inland, from about the 70th meridian eastward to the Atlanticcoast, the amount varies between 70 and 75 per cent. 

(3) The dry region is in the Southwest, where the average annualvalue is not over 50 per cent. In this region are included Arizona, New Mexico, western Colorado, and the greater portion of both Utahand Nevada. The amount of annual relative humidity in the remainingportion of the elevated district, between the 100th meridian on theeast to the Sierra Nevada and the Cascades on the west, variesbetween 55 and 65 per cent. In July, August, and September, the meanvalues in the Southwest sink as low as 20 to 30 per cent, whilealong the Pacific coast districts they continue about 80 per centthe year round. In the Atlantic coast districts, and generally eastfrom the Mississippi River, the variation from month to month is notgreat. April is probably the driest month of the year. 

The air of the dry-farm territory, therefore, on the whole, containsconsiderably less than two thirds the amount of moisture carried bythe air of the humid states. This means that evaporation from plantleaves and soil surfaces will go on more rapidly in semiarid than inhumid regions. Against this danger, which cannot he controlled, thedry-farmer must take special precautions. 

Sunshine

The amount of sunshine in a dry-farm section is also of importance. Direct sunshine promotes plant growth, but at the same time itaccelerates the evaporation of water from the soil. The wholedry-farm territory receives more sunshine than do the humidsections. In fact, the amount of sunshine may roughly be said toincrease as the annual rainfall decreases. Over the larger part ofthe arid and semiarid sections the sun shines over 70 per cent ofthe time. 

Winds

The winds of any locality, owing to their moisture-dissipatingpower play an important part in the success of dry-farming. Apersistent wind will offset much of the benefit of a heavy rainfalland careful cultivation. While great general laws have beenformulated regarding the movements of the atmosphere, they are ofminor value in judging the effect of wind on any farming district. Local observations, however, may enable the farmer to estimate theprobable effect of the winds and thus to formulate proper culturalmeans of protection. In general, those living in a district are ableto describe it without special observations as windy or quiet. Inthe dry-farm territory of the United States the one great region ofrelatively high and persistent winds is the Great Plains region eastof the Rocky Mountains. Dry-farmers in that section will ofnecessity be obliged to adopt cultural methods that will prevent theexcessive evaporation naturally induced by the unhindered wind, andthe possible blowing of well-tilled fallow land. 

Summary

The dry-farm territory is characterized by a low rainfall, averagingbetween 10 and 20 inches, the distribution of which falls into twodistinct types: a heavy winter and spring with a light summerprecipitation, and a heavy spring and summer with a light winterprecipitation. Snow falls over most of the territory, but does notlie long outside of the mountain states. The whole dry-farmterritory may be classed as temperate to cold; relatively high andpersistent winds blow only over the Great Plains, though localconditions cause strong regular winds in many other places; the airis dry and the sunshine is very abundant. In brief, little waterfalls upon the dry-farm territory, and the climatic factors are of anature to cause rapid evaporation. 

In view of this knowledge, it is not surprising that thousands offarmers, employing, often carelessly agricultural methods developedin humid sections, have found only hardships and poverty on thepresent dry-farm empire of the United States. 

Drouth

Drouth is said to be the arch enemy of the dry-farmer, but few agreeupon its meaning. For the purposes of this volume, drouth may bedefined as a condition under which crops fail to mature because ofan insufficient supply of water. Providence has generally beencharged with causing drouths, but under the above definition, man isusually the cause. Occasionally, relatively dry years occur, butthey are seldom dry enough to cause crop failures if proper methodsof farming have been practiced. There are four chief causes ofdrouth: (1) Improper or careless preparation of the soil; (2)failure to store the natural precipitation in the soil; (3) failureto apply proper cultural methods for keeping the moisture in thesoil until needed by plants, and (4) sowing too much seed for theavailable soil-moisture. 

Crop failures due to untimely frosts, blizzards, cyclones, tornadoes, or hail may perhaps be charged to Providence, but thedry-farmer must accept the responsibility for any crop injuryresulting from drouth. A fairly accurate knowledge of the climaticconditions of the district, a good understanding of the principlesof agriculture without irrigation under a low rainfall, and avigorous application of these principles as adapted to the localclimatic conditions will make dry-farm failures a rarity. 

CHAPTER V

DRY-FARM SOILS

Important as is the rainfall in making dry-farming successful, it isnot more so than the soils of the dry-farms. On a shallow soil, oron one penetrated with gravel streaks, crop failures are probableeven under a large rainfall; but a deep soil of uniform texture, unbroken by gravel or hardpan, in which much water may be stored, and which furnishes also an abundance of feeding space for theroots, will yield large crops even under a very small rainfall. Likewise, an infertile soil, though it be deep, and under a largeprecipitation, cannot be depended on for good crops; but a fertilesoil, though not quite so deep, nor under so large a rainfall, willalmost invariably bring large crops to maturity. 

A correct understanding of the soil, from the surface to a depth often feet, is almost indispensable before a safe Judgment can bepronounced upon the full dry-farm possibilities of a district. Especially is it necessary to know (a) the depth, (b) the uniformityof structure, and (c) the relative fertility of the soil, in orderto plan an intelligent system of farming that will be rationallyadapted to the rainfall and other climatic factors. 

It is a matter of regret that so much of our information concerningthe soils of the dry-farm territory of the United States and othercountries has been obtained according to the methods and for theneeds of humid countries, and that, therefore, the special knowledgeof our arid and semiarid soils needed for the development ofdry-farming is small and fragmentary. What is known to-dayconcerning the nature of arid soils and their relation to culturalprocesses under a scanty rainfall is due very largely to theextensive researches and voluminous writings of Dr. E. W. Hilgard, who for a generation was in charge of the agricultural work of thestate of California. Future students of arid soils must of necessityrest their investigations upon the pioneer work done by Dr. Hilgard. The contents of this chapter are in a large part gathered fromHilgard's writings. 

The formation of soils

"Soil is the more or less loose and friable material in which, bymeans of their roots, plants may or do find a foothold andnourishment, as well as other conditions of growth. " Soil is formedby a complex process, broadly known as _weathering, _from the rockswhich constitute the earth's crust. Soil is in fact only pulverizedand altered rock. The forces that produce soil from rocks are of twodistinct classes, _physical and chemical. _The physical agencies ofsoil production merely cause a pulverization of the rock; thechemical agencies, on the other hand, so thoroughly change theessential nature of the soil particles that they are no longer likethe rock from which they were formed. 

Of the physical agencies, _temperature changes _are first in orderof time, and perhaps of first importance. As the heat of the dayincreases, the rock expands, and as the cold night approaches, contracts. This alternate expansion and contraction, in time, cracksthe surfaces of the rocks. Into the tiny crevices thus formed waterenters from the falling snow or rain. When winter comes, the waterin these cracks freezes to ice, and in so doing expands and widenseach of the cracks. As these processes are repeated from day to day, from year to year, and from generation to generation, the surfacesof the rocks crumble. The smaller rocks so formed are acted upon bythe same agencies, in the same manner, and thus the process ofpulverization goes on. 

It is clear, then, that the second great agency of soil formation, which always acts in conjunction with temperature changes, is_freezing water. _The rock particles formed in this manner are oftenwashed down into the mountain valleys, there caught by great rivers, ground into finer dust, and at length deposited in the lowervalleys. _Moving water _thus becomes another physical agency of soilproduction. Most of the soils covering the great dry-farm territoryof the United States and other countries have been formed in thisway. 

In places, glaciers moving slowly down the canons crush and grindinto powder the rock over which they pass and deposit it lower downas soils. In other places, where strong winds blow with frequentregularity, sharp soil grains are picked up by the air and hurledagainst the rocks, which, under this action, are carved intofantastic forms. In still other places, the strong winds carry soilover long distances to be mixed with other soils. Finally, on theseashore the great waves dashing against the rocks of the coastline, and rolling the mass of pebbles back and forth, break andpulverize the rock until soil is formed. _ Glaciers, winds, _and_waves _are also, therefore, physical agencies of soil formation. 

It may be noted that the result of the action of all these agenciesis to form a rock powder, each particle of which preserves thecomposition that it had while it was a constituent part of the rock. It may further be noted that the chief of these soil-formingagencies act more vigorously in arid than in humid sections. Underthe cloudless sky and dry atmosphere of regions of limited rainfall, the daily and seasonal temperature changes are much greater than insections of greater rainfall. Consequently the pulverization ofrocks goes on most rapidly in dry-farm districts. Constant heavywinds, which as soil formers are second only to temperature changesand freezing water, are also usually more common in arid than inhumid countries. This is strikingly shown, for instance, on theColorado desert and the Great Plains. 

The rock powder formed by the processes above described iscontinually being acted upon by agencies, the effect of which is tochange its chemical composition. Chief of these agencies is _water, _which exerts a solvent action on all known substances. Pure waterexerts a strong solvent action, but when it has been rendered impureby a variety of substances, naturally occurring, its solvent actionis greatly increased. 

The most effective water impurity, considering soil formation, isthe gas, _carbon dioxid. _This gas is formed whenever plant oranimal substances decay, and is therefore found, normally, in theatmosphere and in soils. Rains or flowing water gather the carbondioxid from the atmosphere and the soil; few natural waters are freefrom it. The hardest rock particles are disintegrated by carbonatedwater, while limestones, or rocks containing lime, are readilydissolved. 

The result of the action of carbonated water upon soil particles isto render soluble, and therefore more available to plants, many ofthe important plant-foods. In this way the action of water, holdingin solution carbon dioxid and other substances, tends to make thesoil more fertile. 

The second great chemical agency of soil formation is the oxygen ofthe air. Oxidation is a process of more or less rapid burning, whichtends to accelerate the disintegration of rocks. 

Finally, the _plants _growing in soils are powerful agents of soilformation. First, the roots forcing their way into the soil exert astrong pressure which helps to pulverize the soil grains; secondly, the acids of the plant roots actually dissolve the soil, and third, in the mass of decaying plants, substances are formed, among themcarbon dioxid, that have the power of making soils more soluble. 

It may be noted that moisture, carbon dioxid, and vegetation, thethree chief agents inducing chemical changes in soils, are mostactive in humid districts. While, therefore, the physical agenciesof soil formation are most active in arid climates, the same cannotbe said of the chemical agencies. However, whether in arid or humidclimates, the processes of soil formation, above outlined, areessentially those of the "fallow" or resting-period given todry-farm lands. The fallow lasts for a few months or a year, whilethe process of soil formation is always going on and has gone on forages; the result, in quality though not in quantity, is thesame--the rock particles are pulverized and the plant-foods areliberated. It must be remembered in this connection that climaticdifferences may and usually do influence materially the character ofsoils formed from one and the same kind of rock. 

Characteristics of arid soils

The net result of the processes above described Is a rock powdercontaining a great variety of sizes of soil grains intermingled withclay. The larger soil grains are called sand; the smaller, silt, andthose that are so small that they do not settle from quiet waterafter 24 hours are known as clay. 

Clay differs materially from sand and silt, not only in size ofparticles, but also in properties and formation. It is said thatclay particles reach a degree of fineness equal to 1/2500 of aninch. Clay itself, when wet and kneaded, becomes plastic andadhesive and is thus easily distinguished from sand. Because ofthese properties, clay is of great value in holding together thelarger soil grains in relatively large aggregates which give soilsthe desired degree of filth. Moreover, clay is very retentive ofwater, gases, and soluble plant-foods, which are important factorsin successful agriculture. Soils, in fact, are classified accordingto the amount of clay that they contain. Hilgard suggests thefollowing classification:--

Very sandy soils 0. 5 to 3 per cent clayOrdinary sandy soils 3. 0 to 10 per cent claySandy loams 10. 0 to 15 per cent clayClay loams 15. 0 to 25 per cent clayClay soils 25. 0 to 35 per cent clayHeavy clay soils 35. 0 per cent and over

Clay may be formed from any rock containing some form of _combinedsilica _(quartz). Thus, granites and crystalline rocks generally, volcanic rocks, and shales will produce clay if subjected to theproper climatic conditions. In the formation of clay, the extremelyfine soil particles are attacked by the soil water and subjected todeep-going chemical changes. In fact, clay represents the mostfinely pulverized and most highly decomposed and hence in a measurethe most valuable portion of the soil. In the formation of clay, water is the most active agent, and under humid conditions itsformation is most rapid. 

It follows that dry-farm soils formed under a more or less rainlessclimate contain less clay than do humid soils. This difference ischaracteristic, and accounts for the statement frequently made thatheavy clay soils are not the best for dry-farm purposes. The factis, that heavy clay soils are very rare in arid regions; if found atall, they have probably been formed under abnormal conditions, as inhigh mountain valleys, or under prehistoric humid climates. 

_Sand. --_The sand-forming rocks that are not capable of clayproduction usually consist of _uncombined silica _or quartz, whichwhen pulverized by the soil-forming agencies give a comparativelybarren soil. Thus it has come about that ordinarily a clayey soil isconsidered "strong" and a sandy soil "weak. " Though this distinctionis true in humid climates where clay formation is rapid, it is nottrue in arid climates, where true clay is formed very slowly. Underconditions of deficient rainfall, soils are naturally less clayey, but as the sand and silt particles are produced from rocks whichunder humid conditions would yield clay, arid soils are notnecessarily less fertile. 

Experiment has shown that the fertility in the sandy soils of aridsections is as large and as available to plants as in the clayeysoils of humid regions. Experience in the arid section of America, in Egypt, India, and other desert-like regions has further provedthat the sands of the deserts produce excellent crops whenever wateris applied to them. The prospective dry-farmer, therefore, need notbe afraid of a somewhat sandy soil, provided it has been formedunder arid conditions. In truth, a degree of sandiness ischaracteristic of dry-farm soils. 

The _humus _content forms another characteristic difference betweenarid and humid soils. In humid regions plants cover the soilthickly; in arid regions they are bunched scantily over the surface;in the former case the decayed remnants of generations of plantsform a large percentage of humus in the upper soil; in the latter, the scarcity of plant life makes the humus content low. Further, under an abundant rainfall the organic matter in the soil rotsslowly; whereas in dry warm climates the decay is very complete. Theprevailing forces in all countries of deficient rainfall thereforetend to yield soils low in humus. 

While the total amount of humus in arid soils is very much lowerthan in humid soils, repeated investigation has shown that itcontains about 3-1/2 times more nitrogen than is found in humusformed under an abundant rainfall. Owing to the prevailing sandinessof dry-farm soils, humus is not needed so much to give the properfilth to the soil as in the humid countries where the content ofclay is so much higher. Since, for dry-farm purposes, the nitrogencontent is the most important quality of the humus, the differencebetween arid and humid soils, based upon the humus content, is notso great as would appear at first sight. 

_Soil and subsoil. --_In countries of abundant rainfall, a greatdistinction exists between the soil and the subsoil. The soil isrepresented by the upper few inches which are filled with theremnants of decayed vegetable matter and modified by plowing, harrowing, and other cultural operations. The subsoil has beenprofoundly modified by the action of the heavy rainfall, which, insoaking through the soil, has carried with it the finest soilgrains, especially the clay, into the lower soil layers. 

In time, the subsoil has become more distinctly clayey than thetopsoil. Lime and other soil ingredients have likewise been carrieddown by the rains and deposited at different depths in the soil orwholly washed away. Ultimately, this results in the removal from thetopsoil of the necessary plant-foods and the accumulation in thesubsoil of the fine clay particles which so compact the subsoil asto make it difficult for roots and even air to penetrate it. Thenormal process of weathering or soil disintegration will then go onmost actively in the topsoil and the subsoil will remain unweatheredand raw. This accounts for the well-known fact that in humidcountries any subsoil that may have been plowed up is reduced to anormal state of fertility and crop production only after severalyears of exposure to the elements. The humid farmer, knowing this, is usually very careful not to let his plow enter the subsoil to anygreat depth. 

In the arid regions or wherever a deficient rainfall prevails, theseconditions are entirely reversed. The light rainfall seldomcompletely fills the soil pores to any considerable depth, but itrather moves down slowly as a him, enveloping the soil grains. Thesoluble materials of the soil are, in part at least, dissolved andcarried down to the lower limit of the rain penetration, but theclay and other fine soil particles are not moved downward to anygreat extent. These conditions leave the soil and subsoil ofapproximately equal porosity. Plant roots can then penetrate thesoil deeply, and the air can move up and down through the soil massfreely and to considerable depths. As a result, arid soils areweathered and made suitable for plant nutrition to very greatdepths. In fact, in dry-farm regions there need be little talk aboutsoil and subsoil, since the soil is uniform in texture and usuallynearly so in composition, from the top down to a distance of manyfeet. 

Many soil sections 50 or more feet in depth are exposed in thedry-farming territory of the United States, and it has often beendemonstrated that the subsoil to any depth is capable of producing, without further weathering, excellent yields of crops. Thisgranular, permeable structure, characteristic of arid soils, isperhaps the most important single quality resulting from rockdisintegration under arid conditions. As Hilgard remarks, it wouldseem that the farmer in the arid region owns from three to fourfarms, one above the other, as compared with the same acreage in theeastern states. 

This condition is of the greatest importance in developing theprinciples upon which successful dry-farming rests. Further, it maybe said that while in the humid East the farmer must be extremelycareful not to turn up with his plow too much of the inert subsoil, no such fear need possess the western farmer. On the contrary, heshould use his utmost endeavor to plow as deeply as possible inorder to prepare the very best reservoir for the falling waters anda place for the development of plant roots. 

_Gravel seams. --_It need be said, however, that in a number oflocalities in the dry-farm territory the soils have been depositedby the action of running water in such a way that the otherwiseuniform structure of the soil is broken by occasional layers ofloose gravel. While this is not a very serious obstacle to thedownward penetration of roots, it is very serious in dry-farming, since any break in the continuity of the soil mass prevents theupward movement of water stored in the lower soil depths. Thedry-farmer should investigate the soil which he intends to use to adepth of at least 8 to 10 feet to make sure, first of all, that hehas a continuous soil mass, not too clayey in the lower depths, norbroken by deposits of gravel. 

_Hardpan. --_Instead of the heavy clay subsoil of humid regions, theso-called hardpan occurs in regions of limited rainfall. The annualrainfall, which is approximately constant, penetrates from year toyear very nearly to the same depth. Some of the lime found soabundantly in arid soils is dissolved and worked down yearly to thelower limit of the rainfall and left there to enter into combinationwith other soil ingredients. Continued through long periods of timethis results in the formation of a layer of calcareous material atthe average depth to which the rainfall has penetrated the soil. Notonly is the lime thus carried down, but the finer particles arecarried down in like manner. Especially where the soil is poor inlime is the clay worked down to form a somewhat clayey hardpan. Ahardpan formed in such a manner is frequently a serious obstacle tothe downward movement of the roots, and also prevents the annualprecipitation from moving down far enough to be beyond the influenceof the sunshine and winds. It is fortunate, however, that in thegreat majority of instances this hardpan gradually disappears underthe influence of proper methods of dry-farm tillage. Deep plowingand proper tillage, which allow the rain waters to penetrate thesoil, gradually break up and destroy the hardpan, even when it is 10feet below the surface. Nevertheless, the farmer should make surewhether or not the hardpan does exist in the soil and plan hismethods accordingly. If a hardpan is present, the land must befallowed more carefully every other year, so that a large quantityof water may be stored in the soil to open and destroy the hardpan. 

Of course, in arid as in humid countries, it often happens that asoil is underlaid, more or less near the surface, by layers of rock, marl deposits, and similar impervious or hurtful substances. Suchdeposits are not to be classed with the hardpans that occur normallywherever the rainfall is small. 

_Leaching. --_Fully as important as any of the differences aboveoutlined are those which depend definitely upon the leaching powerof a heavy rainfall. In countries where the rainfall is 30 inches orover, and in many places where the rainfall is considerably less, the water drains through the soil into the standing ground water. There is, therefore, in humid countries, a continuous drainagethrough the soil after every rain, and in general there is a steadydownward movement of soil-water throughout the year. As is clearlyshown by the appearance, taste, and chemical composition of drainagewaters, this process leaches out considerable quantities of thesoluble constituents of the soil. 

When the soil contains decomposing organic matter, such as roots, leaves, stalks, the gas carbon dioxid is formed, which, whendissolved in water, forms a solution of great solvent power. Waterpassing through well-cultivated soils containing much humus leachesout very much more material than pure water could do. A study of thecomposition of the drainage waters from soils and the waters of thegreat rivers shows that immense quantities of soluble soilconstituents are taken out of the soil in countries of abundantrainfall. These materials ultimately reach the ocean, where they areand have been concentrated throughout the ages. In short, thesaltiness of the ocean is due to the substances that have beenwashed from the soils in countries of abundant rainfall. 

In arid regions, on the other hand, the rainfall penetrates the soilonly a few feet. In time, it is returned to the surface by theaction of plants or sunshine and evaporated into the air. It is truethat under proper methods of tillage even the light rainfall of aridand semiarid regions may he made to pass to considerable soildepths, yet there is little if any drainage of water through thesoil into the standing ground water. The arid regions of the world, therefore, contribute proportionately a small amount of thesubstances which make up the salt of the sea. 

_Alkali soils. --_Under favorable conditions it sometimes happensthat the soluble materials, which would normally be washed out ofhumid soils, accumulate to so large a degree in arid soils as tomake the lands unfitted for agricultural purposes. Such lands arecalled alkali lands. Unwise irrigation in arid climates frequentlyproduces alkali spots, but many occur naturally. Such soils shouldnot be chosen for dry-farm purposes, for they are likely to givetrouble. 

_Plant-food content. --_This condition necessarily leads at once tothe suggestion that the soils from the two regions must differgreatly in their fertility or power to produce and sustain plantlife. It cannot be believed that the water-washed soils of the Eastretain as much fertility as the dry soils of the West. Hilgard hasmade a long and elaborate study of this somewhat difficult questionand has constructed a table showing the composition of typical soilsof representative states in the arid and humid regions. Thefollowing table shows a few of the average results obtained byhim:--

Partial Percentage Composition

Source of soil Humid AridNumber of samples analyzed 696 573Insoluble residue 84. 17 69. 16Soluble silica 4. 04 6. 71Alumina 3. 66 7. 61Lime 0. 13 1. 43Potash 0. 21 0. 67Phos. Acid 0. 12 0. 16Humus 1. 22 1. 13

Soil chemists have generally attempted to arrive at a determinationof the fertility of soil by treating a carefully selected andprepared sample with a certain amount of acid of definite strength. The portion which dissolves under the influence of acids has beenlooked upon as a rough measure of the possible fertility of thesoil. 

The column headed "Insoluble Residue" shows the average proportionsof arid and humid soils which remain undissolved by acids. It isevident at once that the humid soils are much less soluble in acidsthan arid soils, the difference being 84 to 69. Since the onlyplant-food in soils that may be used for plant production is thatwhich is soluble, it follows that it is safe to assume that aridsoils are generally more fertile than humid soils. This is borne outby a study of the constituents of the soil. For instance, potash, one of the essential plant foods ordinarily present in sufficientamount, is found in humid soils to the extent of 0. 21 per cent, while in arid soils the quantity present is 0. 67 per cent, or overthree times as much. Phosphoric acid, another of the very importantplant-foods, is present in arid soils in only slightly higherquantities than in humid soils. This explains the somewhatwell-known fact that the first fertilizer ordinarily required byarid soils is some form of phosphorus:

The difference in the chemical composition of arid and humid soilsis perhaps shown nowhere better than in the lime content. There isnearly eleven times more lime in arid than in humid soils. Conditions of aridity favor strongly the formation of lime, andsince there is very little leaching of the soil by rainfall, thelime accumulates in the soil. 

The presence of large quantities of lime in arid soils has a numberof distinct advantages, among which the following are mostimportant: (1) It prevents the sour condition frequently present inhumid climates, where much organic material is incorporated with thesoil. (2) When other conditions are favorable, it encouragesbacterial life which, as is now a well-known fact, is an importantfactor in developing and maintaining soil fertility. (3) By somewhatsubtle chemical changes it makes the relatively small percentages ofother plant-foods notably phosphoric acid and potash, more availablefor plant growth. (4) It aids to convert rapidly organic matter intohumus which represents the main portion of the nitrogen content ofthe soil. 

Of course, an excess of lime in the soil may be hurtful, though lessso in arid than in humid regions. Some authors state that from 8 to20 per cent of calcium carbonate makes a soil unfitted for plantgrowth. There are, however, a great many agricultural soils coveringlarge areas and yielding very abundant crops which contain very muchlarger quantities of calcium carbonate. For instance, in the SanpeteValley of Utah, one of the most fertile sections of the Great Basin, agricultural soils often contain as high as 40 per cent of calciumcarbonate, without injury to their crop-producing power. 

In the table are two columns headed "Soluble Silica" and "Alumina, "in both of which it is evident that a very much larger per cent isfound in the arid than in the humid soils. These soil constituentsindicate the condition of the soil with reference to theavailability of its fertility for plant use. The higher thepercentage of soluble silica and alumina, the more thoroughlydecomposed, in all probability, is the soil as a whole and the morereadily can plants secure their nutriment from the soil. It will beobserved from the table, as previously stated, that more humus isfound in humid than in arid soils, though the difference is not solarge as might be expected. It should be recalled, however, that thenitrogen content of humus formed under rainless conditions is manytimes larger than that of humus formed in rainy countries, and thatthe smaller per cent of humus in dry-farming countries is therebyoffset. 

All in all, the composition of arid soils is very much morefavorable to plant growth than that of humid soils. As will be shownin Chapter IX, the greater fertility of arid soils is one of thechief reasons for dry-farming success. Depth of the soil alone doesnot suffice. There must be a large amount of high fertilityavailable for plants in order that the small amount of water can befully utilized in plant growth. 

_Summary of characteristics. --_Arid soils differ from humid soils inthat they contain: less clay; more sand, but of fertile naturebecause it is derived from rocks that in humid countries wouldproduce clay; less humus, but that of a kind which contains about3-1/2 times more nitrogen than the humus of humid soils; more lime, which helps in a variety of ways to improve the agricultural valueof soils; more of all the essential plant-foods, because theleaching by downward drainage is very small in countries of limitedrainfall. 

Further, arid soils show no real difference between soil andsubsoil; they are deeper and more permeable; they are more uniformin structure; they have hardpans instead of clay subsoil, which, however, disappear under the influence of cultivation; theirsubsoils to a depth of ten feet or more are as fertile as thetopsoil, and the availability of the fertility is greater. Thefailure to recognize these characteristic differences between aridand humid soils has been the chief cause for many crop failures inthe more or less rainless regions of the world. 

This brief review shows that, everything considered, arid soils aresuperior to humid soils. In ease of handling, productivity, certainty of crop-lasting quality, they far surpass the soils of thecountries in which scientific agriculture was founded. As Hilgardhas suggested, the historical datum that the majority of the mostpopulous and powerful historical peoples of the world have beenlocated on soils that thirst for water, may find its explanation inthe intrinsic value of arid soils. From Babylon to the United Statesis a far cry; but it is one that shouts to the world the superlativemerits of the soil that begs for water. To learn how to use the"desert" is to make it "blossom like the rose. "

Soil divisions

The dry-farm territory of the United States may be divided roughlyinto five great soil districts, each of which includes a greatvariety of soil types, most of which are poorly known and mapped. These districts are:--

1. Great Plains district. 2. Columbia River district3. Great Basin district. 4. Colorado River district. 5. California district. 

_Great Plains district. --_On the eastern slope of the RockyMountains, extending eastward to the extreme boundary of thedry-farm territory, are the soils of the High Plains and the GreatPlains. This vast soil district belongs to the drainage basin of theMissouri, and includes North and South Dakota, Nebraska, Kansas, Oklahoma, and parts of Montana, Wyoming, Colorado, New Mexico, Texas, and Minnesota. The soils of this district are usually of highfertility. They have good lasting power, though the effect of thehigher rainfall is evident in their composition. Many of thedistinct types of the plains soils have been determined withconsiderable care by Snyder and Lyon, and may be found described inBailey's "Cyclopedia of American Agriculture, " Vol. I. 

_Columbia River district. --_The second great soil district of thedry-farming territory is located in the drainage basin of theColumbia River, and includes Idaho and the eastern two thirds ofWashington and Oregon. The high plains of this soil district areoften spoken of as the Palouse country. The soils of the westernpart of this district are of basaltic origin; over the southern partof Idaho the soils have been made from a somewhat recent lava flowwhich in many places is only a few feet below the surface. The soilsof this district are generally of volcanic origin and very muchalike. They are characterized by the properties which normallybelong to volcanic soils; somewhat poor in lime, but rich in potashand phosphoric acid. They last well under ordinary methods oftillage. 

_The Great Basin. --_The third great soil district is included in theGreat Basin, which covers nearly all of Nevada, half of Utah, andtakes small portions out of Idaho, Oregon, and southern California. This basin has no outlet to the sea. Its rivers empty into greatsaline inland lakes, the chief of which is the Great Salt Lake. Thesizes of these interior lakes are determined by the amounts of waterflowing into them and the rates of evaporation of the water into thedry air of the region. 

In recent geological times, the Great Basin was filled with water, forming a vast fresh-water lake known as Lake Bonneville, whichdrained into the Columbia River. During the existence of this lake, soil materials were washed from the mountains into the lake anddeposited on the lake bottom. When at length, the lake disappeared, the lake bottom was exposed and is now the farming lands of theGreat Basin district. The soils of this district are characterizedby great depth and uniformity, an abundance of lime, and all theessential plant-foods with the exception of phosphoric acid, which, while present in normal quantities, is not unusually abundant. TheGreat Basin soils are among the most fertile on the AmericanContinent. 

_Colorado River district. --_The fourth soil district lies in thedrainage basin of the Colorado River It includes much of thesouthern part of Utah, the eastern part of Colorado, part of NewMexico, nearly all of Arizona, and part of southern California. Thisdistrict, in its northern part, is often spoken of as the HighPlateaus. The soils are formed from the easily disintegrated rocksof comparatively recent geological origin, which themselves are saidto have been formed from deposits in a shallow interior sea whichcovered a large part of the West. The rivers running through thisdistrict have cut immense canons with perpendicular walls which makemuch of this country difficult to traverse. Some of the soils are ofan extremely fine nature, settling firmly and requiring considerabletillage before they are brought to a proper condition of tilth. Inmany places the soils are heavily charged with calcium sulfate, orcrystals of the ordinary land plaster. The fertility of the soils, however, is high, and when they are properly cultivated, they yieldlarge and excellent crops. 

_California district. --_The fifth soil district lies in Californiain the basin of the Sacramento and San Joaquin rivers. The soils areof the typical arid kind of high fertility and great lasting powers. They represent some of the most valuable dry-farm districts of theWest. These soils have been studied in detail by Hilgard. 

_Dry-farming in the five districts. --_It is interesting to note thatin all of these five great soil districts dry-farming has been triedwith great success. Even in the Great Basin and the Colorado Riverdistricts, where extreme desert conditions often prevail and wherethe rainfall is slight, it has been found possible to produceprofitable crops without irrigation. It is unfortunate that thestudy of the dry-farming territory of the United States has notprogressed far enough to permit a comprehensive and correct mappingof its soils. Our knowledge of this subject is, at the best, fragmentary. We know, however, with certainty that the propertieswhich characterize arid soils, as described in this chapter' arepossessed by the soils of the dry-farming territory, including thefive great districts just enumerated. The characteristics of arid idsoils increase as the rainfall decreases and other conditions ofaridity increase. They are less marked as we go eastward or westwardtoward the regions of more abundant rainfall; that is to say, themost highly developed arid soils are found in the Great Basin andColorado River districts. The least developed are on the easternedge of the Great Plains. 

The judging of soils

A chemical analysis of a soil, unless accompanied by a large amountof other information, is of little value to the farmer. The mainpoints in judging a prospective dry-farm are: the depth of the soil, the uniformity of the soil to a depth of at least 10 feet, thenative vegetation, the climatic conditions as relating to early andlate frosts, the total annual rainfall and its distribution, and thekinds and yields of crops that have been grown in the neighborhood. 

The depth of the soil is best determined by the use of an auger. Asimple soil auger is made from the ordinary carpenter's auger, 1-1/2to 2 inches in diameter, by lengthening its shaft to 3 feet or more. Where it is not desirable to carry sectional augers, it is oftenadvisable to have three augers made: one 3 feet, the other 6, andthe third 9 or 10 feet in length. The short auger is used first andthe others afterwards as the depth of the boring increases. Theboring should he made in a large number of averageplaces--preferably one boring or more on each acre if time andcircumstances permit--and the results entered on a map of the farm. The uniformity of the soil is observed as the boring progresses. Ifgravel layers exist, they will necessarily stop the progress of theboring. Hardpans of any kind will also be revealed by such anexamination. 

The climatic information must be gathered from the local weatherbureau and from older residents of the section. 

The native vegetation is always an excellent index of dry-farmpossibilities. If a good stand of native grasses exists, there canscarcely be any doubt about the ultimate success of dry-farmingunder proper cultural methods. A healthy crop of sagebrush is analmost absolutely certain indication that farming without irrigationis feasible. The rabbit brush of the drier regions is also usually agood indication, though it frequently indicates a soil not easilyhandled. Greasewood, shadscale, and other related plants ordinarilyindicate heavy clay soils frequently charged with alkali. Such soilsshould be the last choice for dry-farming purposes, though theyusually give good satisfaction under systems of irrigation. If thenative cedar or other native trees grow in profusion, it is anotherindication of good dry-farm possibilities. 

CHAPTER VI

THE ROOT SYSTEMS OF PLANTS

The great depth and high fertility of the soils of arid and semiaridregions have made possible the profitable production of agriculturalplants under a rainfall very much lower than that of humid regions. To make the principles of this system fully understood, it isnecessary to review briefly our knowledge of the root systems ofplants growing under arid conditions. 

Functions of roots

The roots serve at least three distinct uses or purposes: First, they give the plant a foothold in the earth; secondly, they enablethe plant to secure from the soil the large amount of water neededin plant growth, and, thirdly, they enable the plant to secure theindispensable mineral foods which can be obtained only from thesoil. So important is the proper supply of water and food in thegrowth of a plant that, in a given soil, the crop yield is usuallyin direct proportion to the development of the root system. Wheneverthe roots are hindered in their development, the growth of the plantabove ground is likewise retarded, and crop failure may result. Theimportance of roots is not fully appreciated because they are hiddenfrom direct view. Successful dry-farming consists, largely in theadoption of practices that facilitate a full and free development-ofplant roots. Were it not that the nature of arid soils, as explainedin preceding chapters, is such that full root development iscomparatively easy, it would probably be useless to attempt toestablish a system of dry-farming. 

Kinds of roots

The root is the part of the plant that is found underground. It hasnumerous branches, twigs, and filaments. The root which first formswhen the seed bursts is known as the primary root. From this primaryroot other roots develop, which are known as secondary roots. Whenthe primary root grows more rapidly than the secondary roots, theso-called taproot, characteristic of lucerne, clover, and similarplants, is formed. When, on the other hand, the taproot grows slowlyor ceases its growth, and the numerous secondary roots grow long, afibrous root system results, which is characteristic of the cereals, grasses, corn, and other similar plants. With any type of root, thetendency of growth is downward; though under conditions that are notfavorable for the downward penetration of the roots the lateralextensions may be very large and near the surface

Extent of roots

A number of investigators have attempted to determine the weight ofthe roots as compared with the weight of the plant above ground, hutthe subject, because of its great experimental difficulties, has notbeen very accurately explained. Schumacher, experimenting about1867, found that the roots of a well-established field of cloverweighed as much as the total weight of the stems and leaves of theyear's crop, and that the weight of roots of an oat crop was 43 percent of the total weight of seed and straw. Nobbe, a few yearslater, found in one of his experiments that the roots of timothyweighed 31 per cent of the weight of the hay. Hosaeus, investigatingthe same subject about the same time, found that the weight of rootsof one of the brome grasses was as great as the weight of the partabove ground; of serradella, 77 per cent; of flax, 34 per cent; ofoats, 14 per cent; of barley, 13 per cent, and of peas, 9 per cent. Sanborn, working at the Utah Station in 1893, found results verymuch the same

Although these results are not concordant, they show that the weightof the roots is considerable, in many cases far beyond the belief ofthose who have given the subject little or no attention. It may benoted that on the basis of the figures above obtained, it is veryprobable that the roots in one acre of an average wheat crop wouldweigh in the neighborhood of a thousand pounds--possiblyconsiderably more. It should be remembered that the investigationswhich yielded the preceding results were all conducted in humidclimates and at a time when the methods for the study of the rootsystems were poorly developed. The data obtained, therefore, represent, in all probability, minimum results which would bematerially increased should the work be repeated now. 

The relative weights of the roots and the stems and the leaves donot alone show the large quantity of roots; the total lengths of theroots are even more striking. The German investigator, Nobbe, in alaborious experiment conducted about 1867, added the lengths of allthe fine roots from each of various plants. He found that the totallength of roots, that is, the sum of the lengths of all the roots, of one wheat plant was about 268 feet, and that the total length ofthe roots of one plant of rye was about 385 feet. King, ofWisconsin, estimates that in one of his experiments, one corn plantproduced in the upper 3 feet of soil 1452 feet of roots. Thesesurprisingly large numbers indicate with emphasis the thoroughnesswith which the roots invade the soil. 

Depth of root penetration

The earlier root studies did not pretend to determine the depth towhich roots actually penetrate the earth. In recent years, however, a number of carefully conducted experiments were made by the NewYork, Wisconsin, Minnesota, Kansas, Colorado, and especially theNorth Dakota stations to obtain accurate information concerning thedepth to which agricultural plants penetrate soils. It is somewhatregrettable, for the purpose of dry-farming, that these states, withthe exception of Colorado, are all in the humid or sub-humid area ofthe United States. Nevertheless, the conclusions drawn from the workare such that they may be safely applied in the development of theprinciples of dry-farming. 

There is a general belief among farmers that the roots of allcultivated crops are very near the surface and that few reach agreater depth than one or two feet. The first striking result of theAmerican investigations was that every crop, without exception, penetrates the soil deeper than was thought possible in earlierdays. For example, it was found that corn roots penetrated fullyfour feet into the ground and that they fully occupied all of thesoil to that depth. 

On deeper and somewhat drier soils, corn roots went down as far aseight feet. The roots of the small grains, --wheat, oats, barley, --penetrated the soil from four to eight or ten feet. Variousperennial grasses rooted to a depth of four feet the first year; thenext year, five and one half feet; no determinations were made ofthe depth of the roots in later years, though it had undoubtedlyincreased. Alfalfa was the deepest rooted of all the crops studiedby the American stations. Potato roots filled the soil fully to adepth of three feet; sugar beets to a depth of nearly four feet. 

Sugar Beet Roots

In every case, under conditions prevailing in the experiments, andwhich did not have in mind the forcing of the roots down toextraordinary depths, it seemed that the normal depth of the rootsof ordinary field crops was from three to eight feet. Sub-soilingand deep plowing enable the roots to go deeper into the soil. Thiswork has been confirmed in ordinary experience until there can belittle question about the accuracy of the results. 

Almost all of these results were obtained in humid climates on humidsoils, somewhat shallow, and underlain by a more or less infertilesubsoil. In fact, they were obtained under conditions reallyunfavorable to plant growth. It has been explained in Chapter V thatsoils formed under arid or semiarid conditions are uniformly deepand porous and that the fertility of the subsoil is, in most cases, practically as great as of the topsoil. There is, therefore, in aridsoils, an excellent opportunity for a comparatively easy penetrationof the roots to great depths and, because of the availablefertility, a chance throughout the whole of the subsoil for ampleroot development. Moreover, the porous condition of the soil permitsthe entrance of air, which helps to purify the soil atmosphere andthereby to make the conditions more favorable for root development. Consequently it is to be expected that, in arid regions, roots willordinarily go to a much greater depth than in humid regions. 

It is further to be remembered that roots are in constant search offood and water and are likely to develop in the directions wherethere is the greatest abundance of these materials. Under systems ofdry-farming the soil water is stored more or less uniformly toconsiderable depths--ten feet or more--and in most cases thepercentage of moisture in the spring and summer is as large orlarger some feet below the surface than in the upper two feet. Thetendency of the root is, then, to move downward to depths wherethere is a larger supply of water. Especially is this tendencyincreased by the available soil fertility found throughout the wholedepth of the soil mass. 

It has been argued that in many of the irrigated sections the rootsdo not penetrate the soil to great depths. This is true, because bythe present wasteful methods of irrigation the plant receives somuch water at such untimely seasons that the roots acquire the habitof feeding very near the surface where the water is so lavishlyapplied. This means not only that the plant suffers more greatly intimes of drouth, but that, since the feeding ground of the roots issmaller, the crop is likely to be small. 

These deductions as to the depth to which plant roots will penetratethe soil in arid regions are fully corroborated by experiments andgeneral observation. The workers of the Utah Station have repeatedlyobserved plant roots on dry-farms to a depth of ten feet. Lucerneroots from thirty to fifty feet in length are frequently exposed inthe gullies formed by the mountain torrents. Roots of trees, similarly, go down to great depths. Hilgard observes that he hasfound roots of grapevines at a depth of twenty-two feet below thesurface, and quotes Aughey as having found roots of the nativeShepherdia in Nebraska to a depth of fifty feet. Hilgard furtherdeclares that in California fibrous-rooted plants, such as wheat andbarley, may descend in sandy soils from four to seven feet. Orchardtrees in the arid West, grown properly, are similarly observed tosend their roots down to great depths. In fact, it has become acustom in many arid regions where the soils are easily penetrable tosay that the root system of a tree corresponds in extent andbranching to the part of the tree above ground. 

Now, it is to be observed that, generally, plants grown in dryclimates send their roots straight down into the soil; whereas inhumid climates, where the topsoil is quite moist and the subsoil ishard, roots branch out laterally and fill the upper foot or two ofthe soil. A great deal has been said and written about the danger ofdeep cultivation, because it tends to injure the roots that feednear the surface. However true this may be in humid countries, it isnot vital in the districts primarily interested in dry-farming; andit is doubtful if the objection is as valid in humid countries as isoften declared. True, deep cultivation, especially when performednear the plant or tree, destroys the surface-feeding roots, but thisonly tends to compel the deeper lying roots to make better use ofthe subsoil. 

When, as in arid regions, the subsoil is fertile and furnishes asufficient amount of water, destroying the surface roots is nohandicap whatever. On the contrary, in times of drouth, thedeep-lying roots feed and drink at their leisure far from the hotsun or withering winds, and the plants survive and arrive at richmaturity, while the plants with shallow roots wither and die or areso seriously injured as to produce an inferior crop. Therefore, inthe system of dry-farming as developed in this volume, it must beunderstood that so far as the farmer has power, the roots must bedriven downward into the soil, and that no injury needs to beapprehended from deep and vigorous cultivation. 

One of the chief attempts of the dry-farmer must be to see to itthat the plants root deeply. This can be done only by preparing theright kind of seed-bed and by having the soil in its lower depthswell-stored with moisture, so that the plants may be invited todescend. For that reason, an excess of moisture in the upper soilwhen the young plants are rooting is really an injury to them. 

CHAPTER VII

STORING WATER IN THE SOIL

The large amount of water required for the production of plantsubstance is taken from the soil by the roots. Leaves and stems donot absorb appreciable quantities of water. The scanty rainfall ofdry-farm districts or the more abundant precipitation of humidregions must, therefore, be made to enter the soil in such a manneras to be readily available as soil-moisture to the roots at theright periods of plant growth. 

In humid countries, the rain that falls during the growing season islooked upon, and very properly, as the really effective factor inthe production of large crops. The root systems of plants grownunder such humid conditions are near the surface, ready to absorbimmediately the rains that fall, even if they do not soak deeplyinto the soil. As has been shown in Chapter IV, it is only over asmall portion of the dry-farm territory that the bulk of the scantyprecipitation occurs during the growing season. Over a large portionof the arid and semiarid region the summers are almost rainless andthe bulk of the precipitation comes in the winter, late fall, orearly spring when plants are not growing. If the rains that fallduring the growing season are indispensable in crop production, thepossible area to be reclaimed by dry-farming will be greatlylimited. Even when much of the total precipitation comes in summer, the amount in dry-farm districts is seldom sufficient for the propermaturing of crops. In fact, successful dry-farming depends chieflyupon the success with which the rains that fall during any season ofthe year may be stored and kept in the soil until needed by plantsin their growth. The fundamental operations of dry-farming include asoil treatment which enables the largest possible proportion of theannual precipitation to be stored in the soil. For this purpose, thedeep, somewhat porous soils, characteristic of arid regions, areunusually well adapted. 

Alway's demonstration

An important and unique demonstration of the possibility of bringingcrops to maturity on the moisture stored in the soil at the time ofplanting has been made by Alway. Cylinders of galvanized iron, 6feet long, were filled with soil as nearly as possible in itsnatural position and condition Water was added until seepage began, after which the excess was allowed to drain away. When the seepagehad closed, the cylinders were entirely closed except at thesurface. Sprouted grains of spring wheat were placed in the moistsurface soil, and 1 inch of dry soil added to the surface to preventevaporation. No more water was added; the air of the greenhouse waskept as dry as possible. The wheat developed normally. The first earwas ripe in 132 days after planting and the last in 143 days. Thethree cylinders of soil from semiarid western Nebraska produced 37. 8grams of straw and 29 ears, containing 415 kernels weighing 11. 188grams. The three cylinders of soil from humid eastern Nebraskaproduced only 11. 2 grams of straw and 13 ears containing 114kernels, weighing 3 grams. This experiment shows conclusively thatrains are not needed during the growing season, if the soil is wellfilled with moisture at seedtime, to bring crops to maturity. 

What becomes of the rainfall?

The water that falls on the land is disposed of in three ways:First, under ordinary conditions, a large portion runs off withoutentering the soil; secondly, a portion enters the soil, but remainsnear the surface, and is rapidly evaporated back into the air; and, thirdly, a portion enters the lower soil layers, from which it isremoved at later periods by several distinct processes. The run-offis usually large and is a serious loss, especially in dry-farmingregions, where the absence of luxuriant vegetation, the somewhathard, sun-baked soils, and the numerous drainage channels, formed bysuccessive torrents, combine to furnish the rains with an easyescape into the torrential rivers. Persons familiar with aridconditions know how quickly the narrow box canyons, which oftendrain thousands of square miles, are filled with roaring water aftera comparatively light rainfall. 

The run-off

The proper cultivation of the soil diminishes very greatly the lossdue to run-off, but even on such soils the proportion may often bevery great. Farrel observed at one of the Utah stations that duringa torrential rain--2. 6 inches in 4 hours--the surface of the summerfallowed plats was packed so solid that only one fourth inch, orless than one tenth of the whole amount, soaked into the soil, whileon a neighboring stubble field, which offered greater hindrance tothe run-off, 1-1/2 inches or about 60 per cent were absorbed. 

It is not possible under any condition to prevent the run-offaltogether, although it can usually be reduced exceedingly. It is acommon dry-farm custom to plow along the slopes of the farm insteadof plowing up and down them. When this is done, the water which runsdown the slopes is caught by the succession of furrows and in thatway the runoff is diminished. During the fallow season the disk andsmoothing harrows are run along the hillsides for the same purposeand with results that are nearly always advantageous to thedry-farmer. Of necessity, each man must study his own farm in orderto devise methods that will prevent the run-off. 

The structure of soils

Before examining more closely the possibility of storing water insoils a brief review of the structure of soils is desirable. Aspreviously explained, soil is essentially a mixture of disintegratedrock and the decomposing remains of plants. The rock particles whichconstitute the major portion of soils vary greatly in size. Thelargest ones are often 500 times the sizes of the smallest. It wouldtake 50 of the coarsest sand particles, and 25, 000 of the finestsilt particles, to form one lineal inch. The clay particles areoften smaller and of such a nature that they cannot be accuratelymeasured. The total number of soil particles in even a smallquantity of cultivated soil is far beyond the ordinary limits ofthought, ranging from 125, 000 particles of coarse sand to15, 625, 000, 000, 000 particles of the finest silt in one cubic inch. In other words, if all the particles in one cubic inch of soilconsisting of fine silt were placed side by side, they would form acontinuous chain over a thousand miles long. The farmer, when hetills the soil, deals with countless numbers of individual soilgrains, far surpassing the understanding of the human mind. It isthe immense number of constituent soil particles that gives to thesoil many of its most valuable properties. 

It must be remembered that no natural soil is made up of particlesall of which are of the same size; all sizes, from the coarsest sandto the finest clay, are usually present. These particles of allsizes are not arranged in the soil in a regular, orderly way; theyare not placed side by side with geometrical regularity; they arerather jumbled together in every possible way. The larger sandgrains touch and form comparatively large interstitial spaces intowhich the finer silt and clay grains filter. Then, again, the clayparticles, which have cementing properties, bind, as it were, oneparticle to another. A sand grain may have attached to it hundreds, or it may be thousands, of the smaller silt grains; or a regiment ofsmaller soil grains may themselves be clustered into one large grainby cementing power of the clay. Further, in the presence of lime andsimilar substances, these complex soil grains are grouped into yetlarger and more complex groups. The beneficial effect of lime isusually due to this power of grouping untold numbers of soilparticles into larger groups. When by correct soil culture theindividual soil grains are thus grouped into large clusters, thesoil is said to be in good tilth. Anything that tends to destroythese complex soil grains, as, for instance, plowing the soil whenit is too wet, weakens the crop-producing power of the soil. Thiscomplexity of structure is one of the chief reasons for thedifficulty of understanding clearly the physical laws governingsoils. 

Pore-space of soils

It follows from this description of soil structure that the soilgrains do not fill the whole of the soil space. The tendency israther to form clusters of soil grains which, though touching atmany points, leave comparatively large empty spaces. This pore spacein soils varies greatly, but with a maximum of about 55 per cent. Insoils formed under arid conditions the percentage of pore-space issomewhere in the neighborhood of 50 per cent. There are some aridsoils, notably gypsum soils, the particles of which are so uniformsize that the pore-space is exceedingly small. Such soils are alwaysdifficult to prepare for agricultural purposes. 

It is the pore-space in soils that permits the storage ofsoil-moisture; and it is always important for the farmer so tomaintain his soil that the pore-space is large enough to give himthe best results, not only for the storage of moisture, but for thegrowth and development of roots, and for the entrance into the soilof air, germ life, and other forces that aid in making the soil fitfor the habitation of plants. This can always be best accomplished, as will be shown hereafter, by deep plowing, when the soil is nottoo wet, the exposure of the plowed soil to the elements, thefrequent cultivation of the soil through the growing season, and theadmixture of organic matter. The natural soil structure at depthsnot reached by the plow evidently cannot be vitally changed by thefarmer. 

Hygroscopic soil-water

Under normal conditions, a certain amount of water is always foundin all things occurring naturally, soils included. Clinging to everytree, stone, or animal tissue is a small quantity of moisturevarying with the temperature, the amount of water in the air, andwith other well-known factors. It is impossible to rid any naturalsubstance wholly of water without heating it to a high temperature. This water which, apparently, belongs to all natural objects iscommonly called hygroscopic water. Hilgard states that the soils ofthe arid regions contain, under a temperature of 15 deg C. And anatmosphere saturated with water, approximately 5-1/2 per cent ofhygroscopic water. In fact, however, the air over the arid region isfar from being saturated with water and the temperature is evenhigher than 15 deg C. , and the hygroscopic moisture actually foundin the soils of the dry-farm territory is considerably smaller thanthe average above given. Under the conditions prevailing in theGreat Basin the hygroscopic water of soils varies from . 75 per centto 3-1/2 per cent; the average amount is not far from 12 per cent. 

Whether or not the hygroscopic water of soils is of value in plantgrowth is a disputed question. Hilgard believes that the hygroscopicmoisture can be of considerable help in carrying plants throughrainless summers, and further, that its presence prevents theheating of the soil particles to a point dangerous to plant roots. Other authorities maintain earnestly that the hygroscopic soil-wateris practically useless to plants. Considering the fact that wiltingoccurs long before the hygroscopic water contained in the soil isreached, it is very unlikely that water so held is of any realbenefit to plant growth. 

Gravitational water

It often happens that a portion of the water in the soil is underthe immediate influence of gravitation. For instance, a stone which, normally, is covered with hygroscopic water is dipped into water Thehydroscopic water is not thereby affected, but as the stone is drawnout of the water a good part of the water runs off. This isgravitational water That is, the gravitational water of soils isthat portion of the soil-water which filling the soil pores, flowsdownward through the soil under the influence of gravity. When thesoil pores are completely filled, the maximum amount ofgravitational water is found there. In ordinary dry-farm soils thistotal water capacity is between 35 and 40 per cent of the dry weightof soil. 

The gravitational soil-water cannot long remain in that condition;for, necessarily, the pull of gravity moves it downward through thesoil pores and if conditions are favorable, it finally reaches thestanding water-table, whence it is carried to the great rivers, andfinally to the ocean. In humid soils, under a large precipitation, gravitational water moves down to the standing water-table afterevery rain. In dry-farm soils the gravitational water seldom reachesthe standing water-table; for, as it moves downward, it wets thesoil grains and remains in the capillary condition as a thin filmaround the soil grains. 

To the dry-farmer, the full water capacity is of importance only asit pertains to the upper foot of soil. If, by proper plowing andcultivation, the upper soil be loose and porous, the precipitationis allowed to soak quickly into the soil, away from the action ofthe wind and sun. From this temporary reservoir, the water, inobedience to the pull of gravity, will move slowly downward to thegreater soil depths, where it will be stored permanently untilneeded by plants. It is for this reason that dry-farmers find itprofitable to plow in the fall, as soon as possible afterharvesting. In fact, Campbell advocates that the harvester befollowed immediately by the disk, later to be followed by the plowThe essential thing is to keep the topsoil open and receptive to arain. 

Capillary soil-water

The so-called capillary soil-water is of greatest importance to thedry-farmer. This is the water that clings as a film around a marblethat has been dipped into water. There is a natural attractionbetween water and nearly all known substances, as is witnessed bythe fact that nearly all things may be moistened. The water is heldaround the marble because the attraction between the marble and thewater is greater than the pull of gravity upon the water. Thegreater the attraction, the thicker the film; the smaller theattraction, the thinner the film will be. The water that rises in acapillary glass tube when placed in water does so by virtue of theattraction between water and glass. Frequently, the force that makescapillary water possible is called surface tension. 

Whenever there is a sufficient amount of water available, a thinfilm of water is found around every soil grain; and where the soilgrains touch, or where they are very near together, water is heldpretty much as in capillary tubes. Not only are the soil particlesenveloped by such a film, but the plant roots foraging in the soilare likewise covered; that is, the whole system of soil grains androots is covered, under favorable conditions, with a thin film ofcapillary water. It is the water in this form upon which plants drawduring their periods of growth. The hygroscopic water and thegravitational water are of comparatively little value in plantgrowth. 

Field capacity of soils for capillary water

The tremendously large number of soil grains found in even a smallamount of soil makes it possible for the soil to hold very largequantities of capillary water. To illustrate: In one cubic inch ofsand soil the total surface exposed by the soil grains varies from42 square inches to 27 square feet; in one cubic inch of silt soil, from 27 square feet to 72 square feet, and in one cubic inch of anordinary soil the total surface exposed by the soil grains is about25 square feet. This means that the total surface of the soil grainscontained in a column of soil 1 square foot at the top and 10 feetdeep is approximately 10 acres. When even a thin film of water isspread over such a large area, it is clear that the total amount ofwater involved must be large It is to be noticed, therefore, thatthe fineness of the soil particles previously discussed has a directbearing upon the amount of water that soils may retain for the useof plant growth. As the fineness of the soil grains increases, thetotal surface increases' and the water-holding capacity alsoincreases. 

Naturally, the thickness of a water film held around the soil grainsis very minute. King has calculated that a film 275 millionths of aninch thick, clinging around the soil particles, is equivalent to14. 24 per cent of water in a heavy clay; 7. 2 per cent in a loam;5. 21 per cent in a sandy loam, and 1. 41 per cent in a sandy soil. 

It is important to know the largest amount of water that soils canhold in a capillary condition, for upon it depend, in a measure, thepossibilities of crop production under dry-farming conditions. Kingstates that the largest amount of capillary water that can be heldin sandy loams varies from 17. 65 per cent to 10. 67 per cent; in clayloams from 22. 67 per cent to 18. 16 per cent, and in humus soils(which are practically unknown in dry-farm sections) from 44. 72 percent to 21. 29 per cent. These results were not obtained underdry-farm conditions and must be confirmed by investigations of aridsoils. 

The water that falls upon dry-farms is very seldom sufficient inquantity to reach the standing water-table, and it is necessary, therefore, to determine the largest percentage of water that a soilcan hold under the influence of gravity down to a depth of 8 or 10feet--the depth to which the roots penetrate and in which rootaction is distinctly felt. This is somewhat difficult to determinebecause the many conflicting factors acting upon the soil-water areseldom in equilibrium. Moreover, a considerable time must usuallyelapse before the rain-water is thoroughly distributed throughoutthe soil. For instance, in sandy soils, the downward descent ofwater is very rapid; in clay soils, where the preponderance of fineparticles makes minute soil pores, there is considerable hindranceto the descent of water, and it may take weeks or months forequilibrium to be established. It is believed that in a dry-farmdistrict, where the major part of the precipitation comes duringwinter, the early springtime, before the spring rains come, is thebest time for determining the maximum water capacity of a soil. Atthat season the water-dissipating influences, such as sunshine andhigh temperature, are at a minimum, and a sufficient time haselapsed to permit the rains of fall and winter to distributethemselves uniformly throughout the soil. In districts of highsummer precipitation, the late fall after a fallow season willprobably be the best time for the determination of the field-watercapacity. 

Experiments on this subject have been conducted at the Utah Station. As a result of several thousand trials it was found that, in thespring, a uniform, sandy loam soil of true arid propertiescontained, from year to year, an average of nearly 16-1/2 per centof water to a depth of 8 feet. This appeared to be practically themaximum water capacity of that soil under field conditions, and itmay be called the field capacity of that soil for capillary water. Other experiments on dry-farms showed the field capacity of a claysoil to a depth of 8 feet to be 19 per cent; of a clay loam, to be18 per cent; of a loam, 17 per cent; of another loam somewhat moresandy, 16 per cent; of a sandy loam, 14-1/2 per cent; and of a verysandy loam, 14 per cent. Leather found that in the calcareous aridsoil of India the upper 5 feet contained 18 per cent of water at theclose of the wet season. 

It may be concluded, therefore, that the field-water capacities ofordinary dry-farm soils are not very high, ranging from 15 to 20 percent, with an average for ordinary dry-farm soils in theneighborhood of 16 or 17 per cent. Expressed in another way thismeans that a layer of water from 2 to 3 inches deep can be stored inthe soil to a depth of 12 inches. Sandy soils will hold less waterthan clayey ones. It must not be forgotten that in the dry-farmregion are numerous types of soils, among them some consistingchiefly of very fine soil grains and which would; consequently, possess field-water capacities above the average here stated. Thefirst endeavor of the dry-farmer should be to have the soil filledto its full field-water capacity before a crop is planted. 

Downward movement of soil-moisture

One of the chief considerations in a discussion of the storing ofwater in soils is the depth to which water may move under ordinarydry-farm conditions. In humid regions, where the water table is nearthe surface and where the rainfall is very abundant, no question hasbeen raised concerning the possibility of the descent of waterthrough the soil to the standing water. Considerable objection, however, has been offered to the doctrine that the rainfall of ariddistricts penetrates the soil to any great extent. Numerous writerson the subject intimate that the rainfall under dry-farm conditionsreaches at the best the upper 3 or 4 feet of soil. This cannot betrue, for the deep rich soils of the arid region, which never havebeen disturbed by the husbandman, are moist to very great depths. Inthe deserts of the Great Basin, where vegetation is very scanty, soil borings made almost anywhere will reveal the fact that moistureexists in considerable quantities to the full depth of the ordinarysoil auger, usually 10 feet. The same is true for practically everydistrict of the arid region. 

Such water has not come from below, for in the majority of cases thestanding water is 50 to 500 feet below the surface. Whitney madethis observation many years ago and reported it as a strikingfeature of agriculture in arid regions, worthy of seriousconsideration. Investigations made at the Utah Station have shownthat undisturbed soils within the Great Basin frequently contain, toa depth of 10 feet, an amount of water equivalent to 2 or 3 years ofthe rainfall which normally occurs in that locality. Thesequantities of water could not be found in such soils, unless, underarid conditions, water has the power to move downward toconsiderably greater depths than is usually believed by dry-farmers. 

In a series of irrigation experiments conducted at the Utah Stationit was demonstrated that on a loam soil, within a few hours after anirrigation, some of the water applied had reached the eighth foot, or at least had increased the percentage of water in the eighthfoot. In soil that was already well filled with water, the additionof water was felt distinctly to the full depth of 8 feet. Moreover, it was observed in these experiments that even very small rainscaused moisture changes to considerable depths a few hours after therain was over. For instance, 0. 14 of an inch of rainfall was felt toa depth of 2 feet within 3 hours; 0. 93 of an inch was felt to adepth of 3 feet within the same period. 

To determine whether or not the natural winter precipitation, uponwhich the crops of a large portion of the dry-farm territory depend, penetrates the soil to any great depth a series of tests wereundertaken. At the close of the harvest in August or September thesoil was carefully sampled to a depth of 8 feet, and in thefollowing spring similar samples were taken on the same soils to thesame depth. In every case, it was found that the winterprecipitation had caused moisture changes to the full depth reachedby the soil auger. Moreover, these changes were so great as to leadthe investigators to believe that moisture changes had occurred togreater depths. 

In districts where the major part of the precipitation occurs duringthe summer the same law is undoubtedly in operation; but, sinceevaporation is most active in the summer, it is probable that asmaller proportion reaches the greater soil depths. In the GreatPlains district, therefore, greater care will have to be exercisedduring the summer in securing proper water storage than in the GreatBasin, for instance. The principle is, nevertheless, the same. Burr, working under Great Plains conditions in Nebraska, has shown thatthe spring and summer rains penetrate the soil to the depth of 6feet, the average depth of the borings, and that it undoubtedlyaffects the soil-moisture to the depth of 10 feet. In general, thedry-farmer may safely accept the doctrine that the water that fallsupon his land penetrates the soil far beyond the immediate reach ofthe sun, though not so far away that plant roots cannot make use ofit. 

Importance of a moist subsoil

In the consideration of the downward movement of soil-water it is tobe noted that it is only when the soil is tolerably moist that thenatural precipitation moves rapidly and freely to the deeper soillayers. When the soil is dry, the downward movement of the water ismuch slower and the bulk of the water is then stored near thesurface where the loss of moisture goes on most rapidly. It has beenobserved repeatedly in the investigations at the Utah Station thatwhen desert land is broken for dry-farm purposes and then properlycultivated, the precipitation penetrates farther and farther intothe soil with every year of cultivation. For example, on a dry-farm, the soil of which is clay loam, and which was plowed in the fall of1904 and farmed annually thereafter, the eighth foot contained inthe spring of 1905, 6. 59 per cent of moisture; in the spring of1906, 13. 11 per cent, and in the spring of 1907, 14. 75 per cent ofmoisture. On another farm, with a very sandy soil and also plowed inthe fall of 1904, there was found in the eighth foot in the springof 1905, 5. 63 per cent of moisture, in the spring of 1906, 11. 41 percent of moisture, and in the spring of 1907, 15. 49 per cent ofmoisture. In both of these typical cases it is evident that as thetopsoil was loosened, the full field water capacity of the soil wasmore nearly approached to a greater depth. It would seem that, asthe lower soil layers are moistened, the water is enabled, so tospeak, to slide down more easily into the depths of the soil. 

This is a very important principle for the dry farmer to understand. It is always dangerous to permit the soil of a dry-farm to becomevery dry, especially below the first foot. Dry-farms should be somanipulated that even at the harvesting season a comparatively largequantity of water remains in the soil to a depth of 8 feet or more. The larger the quantity of water in the soil in the fall, the morereadily and quickly will the water that falls on the land during theresting period of fall, winter, and early spring sink into the soiland move away from the topsoil. The top or first foot will alwayscontain the largest percentage of water because it is the chiefreceptacle of the water that falls as rain or snow but when thesubsoil is properly moist, the water will more completely leave thetopsoil. Further, crops planted on a soil saturated with water to adepth of 8 feet are almost certain to mature and yield well. 

If the field-water capacity has not been filled, there is always thedanger that an unusually dry season or a series of hot winds orother like circumstances may either seriously injure the crop orcause a complete failure. The dry-farmer should keep a surplus ofmoisture in the soil to be carried over from year to year, just asthe wise business man maintains a sufficient working capital for theneeds of his business. In fact, it is often safe to advise theprospective dry-farmer to plow his newly cleared or broken landcarefully and then to grow no crop on it the first year, so that, when crop production begins, the soil will have stored in it anamount of water sufficient to carry a crop over periods of drouth. Especially in districts of very low rainfall is this practice to berecommended. In the Great Plains area, where the summer rains temptthe farmer to give less attention to the soil-moisture problem thanin the dry districts with winter precipitation farther West, it isimportant that a fallow season be occasionally given the land toprevent the store of soil moisture from becoming dangerously low. 

To what extent is the rainfall stored in soils?

What proportion of the actual amount of water falling upon the soilcan be stored in the soil and carried over from season to season?This question naturally arises in view of the conclusion that waterpenetrates the soil to considerable depths. There is comparativelylittle available information with which to answer this question, because the great majority of students of soil moisture haveconcerned themselves wholly with the upper two, three, or four feetof soil. The results of such investigations are practically uselessin answering this question. In humid regions it may be verysatisfactory to confine soil-moisture investigations to the upperfew feet; but in arid regions, where dry-farming is a livingquestion, such a method leads to erroneous or incompleteconclusions. 

Since the average field capacity of soils for water is about 2. 5inches per foot, it follows that it is possible to store 25 inchesof water in 10 feet of soil. This is from two to one and a halftimes one year's rainfall over the better dry-farming sections. Theoretically, therefore, there is no reason why the rainfall of oneseason or more could not be stored in the soil. Carefulinvestigations have borne out this theory. Atkinson found, forexample, at the Montana Station, that soil, which to a depth of 9feet contained 7. 7 per cent of moisture in the fall contained 11. 5per cent in the spring and, after carrying it through the summer byproper methods of cultivation, 11 per cent. 

It may certainly be concluded from this experiment that it ispossible to carry over the soil moisture from season to season. Theelaborate investigations at the Utah Station have demonstrated thatthe winter precipitation, that is, the precipitation that comesduring the wettest period of the year, may be retained in a largemeasure in the soil. Naturally, the amount of the naturalprecipitation accounted for in the upper eight feet will depend uponthe dryness of the soil at the time the investigation commenced. Ifat the beginning of the wet season the upper eight feet of soil arefairly well stored with moisture, the precipitation will move downto even greater depths, beyond the reach of the soil auger. If, onthe other hand, the soil is comparatively dry at the beginning ofthe season, the natural precipitation will distribute itself throughthe upper few feet, and thus be readily measured by the soil auger. 

In the Utah investigations it was found that of the water which fellas rain and snow during the winter, as high as 95-1/2 per cent wasfound stored in the first eight feet of soil at the beginning of thegrowing season. Naturally, much smaller percentages were also found, but on an average, in soils somewhat dry at the beginning of the dryseason, more than three fourths of the natural precipitation wasfound stored in the soil in the spring. The results were allobtained in a locality where the bulk of the precipitation comes inthe winter, yet similar results would undoubtedly be obtained wherethe precipitation occurs mainly in the summer. The storage of waterin the soil cannot be a whit less important on the Great Plains thanin the Great Basin. In fact, Burr has clearly demonstrated forwestern Nebraska that over 50 per cent of the rainfall of the springand summer may be stored in the soil to the depth of six feet. Without question, some is stored also at greater depths. 

All the evidence at hand shows that a large portion of theprecipitation falling upon properly prepared soil, whether it besummer or winter, is stored in the soil until evaporation is allowedto withdraw it Whether or not water so stored may be made to remainin the soil throughout the season or the year will be discussed inthe next chapter. It must be said, however, that the possibility ofstoring water in the soil, that is, making the water descend torelatively great soil depths away from the immediate and directaction of the sunshine and winds, is the most fundamental principlein successful dry-farming. 

The fallow

It may be safely concluded that a large portion of the water thatfalls as rain or snow may be stored in the soil to considerabledepths (eight feet or more). However, the question remains, Is itpossible to store the rainfall of successive years in the soil forthe use of one crop? In short, Does the practice of clean fallowingor resting the ground with proper cultivation for one season enablethe farmer to store in the soil the larger portion of the rainfallof two years, to be used for one crop? It is unquestionably true, aswill be shown later, that clean fallowing or "summer tillage" is oneof the oldest and safest practices of dry-farming as practiced inthe West, but it is not generally understood why fallowing isdesirable. 

Considerable doubt has recently been cast upon the doctrine that oneof the beneficial effects of fallowing in dry-farming is to storethe rainfall of successive seasons in the soil for the use of onecrop. Since it has been shown that a large proportion of the winterprecipitation can be stored in the soil during the wet season, itmerely becomes a question of the possibility of preventing theevaporation of this water during the drier season. As will be shownin the next chapter, this can well be effected by propercultivation. 

There is no good reason, therefore, for believing that theprecipitation of successive seasons may not be added to wateralready stored in the soil. King has shown that fallowing the soilone year carried over per square foot, in the upper four feet, 9. 38pounds of water more than was found in a cropped soil in a parallelexperiment; and, moreover, the beneficial effect of this. Wateradvantage was felt for a whole succeeding season. King concludes, therefore, that one of the advantages of fallowing is to increasethe moisture content of the soil. The Utah experiments show that thetendency of fallowing is always to increase the soil-moisturecontent. In dry-farming, water is the critical factor, and anypractice that helps to conserve water should be adopted. For thatreason, fallowing, which gathers soil-moisture, should be stronglyadvocated. In Chapter IX another important value of the fallow willbe discussed. 

In view of the discussion in this chapter it is easily understoodwhy students of soil-moisture have not found a material increase insoil-moisture due to fallowing. Usually such investigations havebeen made to shallow depths which already were fairly well filledwith moisture. Water falling upon such soils would sink beyond thedepth reached by the soil augers, and it became impossible to judgeaccurately of the moisture-storing advantage of the fallow. Acritical analysis of the literature on this subject will reveal theweakness of most experiments in this respect. 

It may be mentioned here that the only fallow that should bepracticed by the dry-farmer is the clean fallow. Water storage ismanifestly impossible when crops are growing upon a soil. A healthycrop of sagebrush, sunflowers, or other weeds consumes as much wateras a first-class stand of corn, wheat, or potatoes. Weeds should beabhorred by the farmer. A weedy fallow is a sure forerunner of acrop failure. How to maintain a good fallow is discussed in ChapterVIII, under the head of Cultivation. Moreover, the practice offallowing should be varied with the climatic conditions. Indistricts of low rainfall, 10-15 inches, the land should be cleansummer-fallowed every other year; under very low rainfall perhapseven two out of three years; in districts of more abundant rainfall, 15-20 inches, perhaps one year out of every three or four issufficient. Where the precipitation comes during the growing season, as in the Great Plains area, fallowing for the storage of water isless important than where the major part of the rainfall comesduring the fall and winter. However, any system of dry-farming thatomits fallowing wholly from its practices is in danger of failure indry years. 

Deep plowing for water storage

It has been attempted in this chapter to demonstrate that waterfalling upon a soil may descend to great depths, and may be storedin the soil from year to year, subject to the needs of the crop thatmay be planted. By what cultural treatment may this downward descentof the water be accelerated by the farmer? First and foremost, byplowing at the right time and to the right depth. Plowing should bedone deeply and thoroughly so that the falling water may immediatelybe drawn down to the full depth of the loose, spongy, plowed soil, away from the action of the sunshine or winds. The moisture thuscaught will slowly work its way down into the lower layers of thesoil. Deep plowing is always to be recommended for successfuldry-farming. 

In humid districts where there is a great difference between thesoil and the subsoil, it is often dangerous to turn up the lifelesssubsoil, but in arid districts where there is no realdifferentiation between the soil and the subsoil, deep plowing maysafely be recommended. True, occasionally, soils are found in thedry-farm territory which are underlaid near the surface by an inertclay or infertile layer of lime or gypsum which forbids the farmerputting the plow too deeply into the soil. Such soils, however' areseldom worth while trying for dry-farm purposes. Deep plowing mustbe practiced for the best dry-farming results. 

It naturally follows that subsoiling should be a beneficial practiceon dry-farms. Whether or not the great cost of subsoiling is offsetby the resulting increased yields is an open question; it is, infact, quite doubtful. Deep plowing done at the right time andfrequently enough is possibly sufficient. By deep plowing is meantstirring or turning the soil to a depth of six to ten inches belowthe surface of the land. 

Fall plowing far water storage

It is not alone sufficient to plow and to plow deeply; it is alsonecessary that the plowing be done at the right time. In the verygreat majority of cases over the whole dry-farm territory, plowingshould be done in the fall. There are three reasons for this: First, after the crop is harvested, the soil should be stirred immediately, so that it can be exposed to the full action of the weatheringagencies, whether the winters be open or closed. If for any reasonplowing cannot be done early it is often advantageous to follow theharvester with a disk and to plow later when convenient. Thechemical effect on the soil resulting from the weathering, madepossible by fall plowing, as will be shown in Chapter IX, is ofitself so great as to warrant the teaching of the general practiceof fall plowing. Secondly, the early stirring of the soil preventsevaporation of the moisture in the soil during late summer and thefall. Thirdly, in the parts of the dry-farm territory where muchprecipitation occurs in the fall, winter, or early spring, fallplowing permits much of this precipitation to enter the soil and bestored there until needed by plants. 

A number of experiment stations have compared plowing done in theearly fall with plowing done late in the fall or in the spring, andwith almost no exception it has been found that early fall plowingis water-conserving and in other ways advantageous. It was observedon a Utah dry-farm that the fall-plowed land contained, to a depthof 10 feet, 7. 47 acre-inches more water than the adjoiningspring-plowed land--a saving of nearly one half of a year'sprecipitation. The ground should be plowed in the early fall as soonas possible after the crop is harvested. It should then be left inthe rough throughout the winter, so that it may be mellowed andbroken down by the elements. The rough lend further has a tendencyto catch and hold the snow that may be blown by the wind, thusinsuring a more even distribution of the water from the meltingsnow. 

A common objection to fall plowing is that the ground is so dry inthe fall that it does not plow up well, and that the great dry clodsof earth do much to injure the physical condition of the soil. It isvery doubtful if such an objection is generally valid, especially ifthe soil is so cropped as to leave a fair margin of moisture in thesoil at harvest time. The atmospheric agencies will usually breakdown the clods, and the physical result of the treatment will bebeneficial. Undoubtedly, the fall plowing of dry land is somewhatdifficult, but the good results more than pay the farmer for histrouble. Late fall plowing, after the fall rains have softened theland, is preferable to spring plowing. If for any reason the farmerfeels that he must practice spring plowing, he should do it as earlyas possible in the spring. Of course, it is inadvisable to plow thesoil when it is so wet as to injure its tilth seriously, but as soonas that danger period has passed, the plow should be placed in theground. The moisture in the soil will thereby be conserved, andwhatever water may fall during the spring months will be conservedalso. This is of especial importance in the Great Plains region andin any district where the precipitation comes in the spring andwinter months. 

Likewise, after fall plowing, the land must be well stirred in theearly spring with the disk harrow or a similar implement, to enablethe spring rains to enter the soil easily and to prevent theevaporation of the water already stored. Where the rainfall is quiteabundant and the plowed land has been beaten down by the frequentrains, the land should be plowed again in the spring. Where suchconditions do not exist, the treatment of the soil with the disk andharrow in the spring is usually sufficient. 

In recent dry-farm experience it has been fairly completelydemonstrated that, providing the soil is well stored with water, crops will mature even if no rain falls during the growing season. Naturally, under most circumstances, any rains that may fall on awell-prepared soil during the season of crop growth will tend toincrease the crop yield, but some profitable yield is assured, inspite of the season, if the soil is well stored with water at seedtime. This is an important principle in the system of dry-farming. 

CHAPTER VIII

REGULATING THE EVAPORATION

The demonstration in the last chapter that the water which falls asrain or snow may be stored in the soil for the use of plants is offirst importance in dry-farming, for it makes the farmerindependent, in a large measure, of the distribution of therainfall. The dry-farmer who goes into the summer with a soil wellstored with water cares little whether summer rains come or not, forhe knows that his crops will mature in spite of external drouth. Infact, as will be shown later, in many dry-farm sections where thesummer rains are light they are a positive detriment to the farmerwho by careful farming has stored his deep soil with an abundance ofwater. Storing the soil with water is, however, only the first stepin making the rains of fall, winter, or the preceding year availablefor plant growth. As soon as warm growing weather comes, water-dissipating forces come into play, and water is lost byevaporation. The farmer must, therefore, use all precautions to keepthe moisture in the soil until such time as the roots of the cropmay draw it into the plants to be used in plant production. That is, as far as possible, direct evaporation of water from the soil mustbe prevented. 

Few farmers really realize the immense possible annual evaporationin the dry-farm territory. It is always much larger than the totalannual rainfall. In fact, an arid region may be defined as one inwhich under natural conditions several times more water evaporatesannually from a free water surface than falls as rain and snow. Forthat reason many students of aridity pay little attention totemperature, relative humidity, or winds, and simply measure theevaporation from a free water surface in the locality in question. In order to obtain a measure of the aridity, MacDougal hasconstructed the following table, showing the annual precipitationand the annual evaporation at several well-known localities in thedry-farm territory. 

True, the localities included in the following table are extreme, but they illustrate the large possible evaporation, ranging fromabout six to thirty-five times the precipitation. At the same timeit must be borne in mind that while such rates of evaporation mayoccur from free water surfaces, the evaporation from agriculturalsoils under like conditions is very much smaller. 

Place Annual Precipitation Annual Evaporation Ratio (In Inches) (In Inches)El Paso, Texas 9. 23 80 8. 7Fort Wingate, New Mexico 14. 00 80 5. 7Fort Yuma, Arizona 2. 84 100 35. 2Tucson, AZ 11. 74 90 7. 7Mohave, CA 4. 97 95 19. 1Hawthorne, Nevada 4. 50 80 17. 5Winnemucca, Nevada 9. 51 80 9. 6St. George, Utah 6. 46 90 13. 9Fort Duchesne, Utah 6. 49 75 11. 6Pineville, Oregon 9. 01 70 7. 8Lost River, Idaho 8. 47 70 8. 3Laramie, Wyoming 9. 81 70 7. 1Torres, Mexico 16. 97 100 6. 0

To understand the methods employed for checking evaporation from thesoil, it is necessary to review briefly the conditions thatdetermine the evaporation of water into the air, and the manner inwhich water moves in the soil. 

The formation of water vapor

Whenever water is left freely exposed to the air, it evaporates;that is, it passes into the gaseous state and mixes with the gasesof the air. Even snow and ice give off water vapor, though in verysmall quantities. The quantity of water vapor which can enter agiven volume of air is definitely limited. For instance, at thetemperature of freezing water 2. 126 grains of water vapor can enterone cubic foot of air, but no more. When air contains all the waterpossible, it is said to be saturated, and evaporation then ceases. The practical effect of this is the well-known experience that onthe seashore, where the air is often very nearly fully saturatedwith water vapor, the drying of clothes goes on very slowly, whereasin the interior, like the dry-farming territory, away from theocean, where the air is far from being saturated, drying goes onvery rapidly. 

The amount of water necessary to saturate air varies greatly withthe temperature. It is to be noted that as the temperatureincreases, the amount of water that may be held by the air alsoincreases; and proportionately more rapidly than the increase intemperature. This is generally well understood in common experience, as in drying clothes rapidly by hanging them before a hot fire. At atemperature of 100 deg F. , which is often reached in portions of thedry-farm territory during the growing season, a given volume of aircan hold more than nine times as much water vapor as at thetemperature of freezing water. This is an exceedingly importantprinciple in dry-farm practices, for it explains the relatively easypossibility of storing water during the fall and winter when thetemperature is low and the moisture usually abundant, and thegreater difficulty of storing the rain that falls largely, as in theGreat Plains area, in the summer when water-dissipating forces arevery active. This law also emphasizes the truth that it is in timesof warm weather that every precaution must be taken to prevent theevaporation of water from the soil surface. 

Temperature Grains of Water held inin Degrees F. One Cubic Foot of Air32 2. 12640 2. 86250 4. 08960 5. 75670 7. 99280 10. 94990 14. 810100 19. 790

It is of course well understood that the atmosphere as a whole isnever saturated with water vapor. Such saturation is at the bestonly local, as, for instance, on the seashore during quiet days, when the layer of air over the water may be fully saturated, or in afield containing much water from which, on quiet warm days, enoughwater may evaporate to saturate the layer of air immediately uponthe soil and around the plants. Whenever, in such cases, the airbegins to move and the wind blows, the saturated air is mixed withthe larger portion of unsaturated air, and evaporation is againincreased. Meanwhile, it must be borne in mind that into a layer ofsaturated air resting upon a field of growing plants very littlewater evaporates, and that the chief water-dissipating power ofwinds lies in the removal of this saturated layer. Winds or airmovements of any kind, therefore, become enemies of the farmer whodepends upon a limited rainfall. 

The amount of water actually found in a given volume of air at acertain temperature, compared with the largest amount it can hold, is called the relative humidity of the air. As shown in Chapter IV, the relative humidity becomes smaller as the rainfall decreases. Thelower the relative humidity is at a given temperature, the morerapidly will water evaporate into the air. There is no more strikingconfirmation of this law than the fact that at a temperature of 90deg sunstrokes and similar ailments are reported in great numberfrom New York, while the people of Salt Lake City are perfectlycomfortable. In New York the relative humidity in summer is about 73per cent; in Salt Lake City, about 35 per cent. At a high summertemperature evaporation from the skin goes on slowly in New York andrapidly in Salt Lake City, with the resulting discomfort or comfort. Similarly, evaporation from soils goes on rapidly under a low andslowly under a high percentage of relative humidity. 

Evaporation from water surfaces is hastened, therefore, by (1) anincrease in the temperature, (2) an increase in the air movements orwinds, and (3) a decrease in the relative humidity. The temperatureis higher; the relative humidity lower, and the winds usually moreabundant in arid than in humid regions. The dry-farmer mustconsequently use all possible precautions to prevent evaporationfrom the soil. 

Conditions of evaporation from from soils

Evaporation does not alone occur from a surface of free water. Allwet or moist substances lose by evaporation most of the water thatthey hold, providing the conditions of temperature and relativehumidity are favorable. Thus, from a wet soil, evaporation iscontinually removing water. Yet, under ordinary conditions, it isimpossible to remove all the water, for a small quantity isattracted so strongly by the soil particles that only a temperatureabove the boiling point of water will drive it out. This part of thesoil is the hygroscopic moisture spoken of in the last chapter. 

Moreover, it must be kept in mind that evaporation does not occur asrapidly from wet soil as from a water surface, unless all the soilpores are so completely filled with water that the soil surface ispractically a water surface. The reason for this reduced evaporationfrom a wet soil is almost self-evident. There is a comparativelystrong attraction between soil and water, which enables the moistureto cling as a thin capillary film around the soil particles, againstthe force of gravity. Ordinarily, only capillary water is found inwell-tilled soil, and the force causing evaporation must be strongenough to overcome this attraction besides changing the water intovapor. 

The less water there is in a soil, the thinner the water film, andthe more firmly is the water held. Hence, the rate of evaporationdecreases with the decrease in soil-moisture. This law is confirmedby actual field tests. For instance, as an average of 274 trialsmade at the Utah Station, it was found that three soils, otherwisealike, that contained, respectively, 22. 63 per cent, 17. 14 per cent, and 12. 75 per cent of water lost in two weeks, to a depth of eightfeet, respectively 21. 0, 17. 1, and 10. 0 pounds of water per squarefoot. Similar experiments conducted elsewhere also furnish proof ofthe correctness of this principle. From this point of view thedry-farmer does not want his soils to be unnecessarily moist. Thedry-farmer can reduce the per cent of water in the soil withoutdiminishing the total amount of water by so treating the soil thatthe water will distribute itself to considerable depths. This bringsinto prominence again the practices of fall plowing, deep plowing, subsoiling, and the choice of deep soils for dry-farming. 

Very much for the same reasons, evaporation goes on more slowly fromwater in which salt or other substances have been dissolved. Theattraction between the water and the dissolved salt seems to bestrong enough to resist partially the force causing evaporation. Soil-water always contains some of the soil ingredients in solution, and consequently under the given conditions evaporation occurs moreslowly from soil-water than from pure water. Now, the more fertile asoil is, that is, the more soluble plant-food it contains, the morematerial will be dissolved in the soil-water, and as a result themore slowly will evaporation take place. Fallowing, cultivation, thorough plowing and manuring, which increase the store of solubleplant-food, all tend to diminish evaporation. While these conditionsmay have little value in the eyes of the farmer who is under anabundant rainfall, they are of great importance to the dry-farmer. It is only by utilizing every possibility of conserving water andfertility that dry-farming may be made a perfectly safe practice. 

Loss by evaporation chiefly at the surface

Evaporation goes on from every wet substance. Water evaporatestherefore from the wet soil grains under the surface as well as fromthose at the surface. In developing a system of practice which willreduce evaporation to a minimum it must be learned whether the waterwhich evaporates from the soil particles far below the surface iscarried in large quantities into the atmosphere and thus lost toplant use. Over forty years ago, Nessler subjected this question toexperiment and found that the loss by evaporation occurs almostwholly at the soil surface, and that very little if any is lostdirectly by evaporation from the lower soil layers. Otherexperimenters have confirmed this conclusion, and very recentlyBuckingham, examining the same subject, found that while there is avery slow upward movement of the soil gases into the atmosphere, thetotal quantity of the water thus lost by direct evaporation fromsoil, a foot below the surface, amounted at most to one inch ofrainfall in six years. This is insignificant even under semiarid andarid conditions. However, the rate of loss of water by directevaporation from the lower soil layers increases with the porosityof the soil, that is, with the space not filled with soil particlesor water. Fine-grained soils, therefore, lose the least water inthis manner. Nevertheless, if coarse-grained soils are well filledwith water, by deep fall plowing and by proper summer fallowing forthe conservation of moisture, the loss of moisture by directevaporation from the lower soil layers need not be larger than fromfiner grained soils

Thus again are emphasized the principles previously laid down that, for the most successful dry-farming, the soil should always be keptwell filled with moisture, even if it means that the land, afterbeing broken, must lie fallow for one or two seasons, until asufficient amount of moisture has accumulated. Further, thecorrelative principle is emphasized that the moisture in dry-farmlands should be stored deeply, away from the immediate action of thesun's rays upon the land surface. The necessity for deep soils isthus again brought out. 

The great loss of soil moisture due to an accumulation of water inthe upper twelve inches is well brought out in the experimentsconducted by the Utah Station. The following is selected from thenumerous data on the subject. Two soils, almost identical incharacter, contained respectively 17. 57 per cent and 16. 55 per centof water on an average to a depth of eight feet; that is, the totalamount of water held by the two soils was practically identical. Owing to varying cultural treatment, the distribution of the waterin the soil was not uniform; one contained 23. 22 per cent and theother 16. 64 per cent of water in the first twelve inches. During thefirst seven days the soil that contained the highest percentage ofwater in the first foot lost 13. 30 pounds of water, while the otherlost only 8. 48 pounds per square foot. This great difference was dueno doubt to the fact that direct evaporation takes place inconsiderable quantity only in the upper twelve inches of soil, wherethe sun's heat has a full chance to act. 

Any practice which enables the rains to sink quickly to considerabledepths should be adopted by the dry-farmer. This is perhaps one ofthe great reasons for advocating the expensive but usually effectivesubsoil plowing on dry-farms. It is a very common experience, in thearid region, that great, deep cracks form during hot weather. Fromthe walls of these cracks evaporation goes on, as from the topsoil, and the passing winds renew the air so that the evaporation may goon rapidly. The dry-farmer must go over the land as often as needsbe with some implement that will destroy and fill up the cracks thatmay have been formed. In a field of growing crops this is oftendifficult to do; but it is not impossible that hand hoeing, expensive as it is, would pay well in the saving of soil moistureand the consequent increase in crop yield. 

How soil water reaches the surface

It may be accepted as an established truth that the directevaporation of water from wet soils occurs almost wholly at thesurface. Yet it is well known that evaporation from the soil surfacemay continue until the soil-moisture to a depth of eight or ten feetor more is depleted. This is shown by the following analyses ofdry-farm soil in early spring and midsummer. No attempt was made toconserve the moisture in the soil:--

Per cent of water in Early spring Midsummer1st foot 20. 84 8. 832nd foot 20. 06 8. 873rd foot 19. 62 11. 034th foot 18. 28 9. 595th foot 18. 70 11. 276th foot 14. 29 11. 037th foot 14. 48 8. 958th foot 13. 83 9. 47Avg 17. 51 9. 88

In this case water had undoubtedly passed by capillary movement fromthe depth of eight feet to a point near the surface where directevaporation could occur. As explained in the last chapter, waterwhich is held as a film around the soil particles is calledcapillary water; and it is in the capillary form that water may bestored in dry-farm soils. Moreover, it is the capillarysoil-moisture alone which is of real value in crop production. Thiscapillary water tends to distribute itself uniformly throughout thesoil, in accordance with the prevailing conditions and forces. If nowater is removed from the soil, in course of time the distributionof the soil-water will be such that the thickness of the film at anypoint in the soil mass is a direct resultant of the various forcesacting at that particular point. There will then be no appreciablemovement of the soil-moisture. Such a condition is approximated inlate winter or early spring before planting begins. During thegreater part of the year, however, no such quiescent state canoccur, for there are numerous disturbing elements that normally areactive, among which the three most effective are (l) the addition ofwater to the soil by rains; (2) the evaporation of water from thetopsoil, due to the more active meteorological factors duringspring, summer, and fall; and (3) the abstraction of water from thesoil by plant roots. 

Water, entering the soil, moves downward under the influence ofgravity as gravitational water, until under the attractive influenceof the soil it has been converted into capillary water and adheresto the soil particles as a film. If the soil were dry, and the filmtherefore thin, the rain water would move downward only a shortdistance as gravitational water; if the soil were wet, and the filmtherefore thick, the water would move down to a greater distancebefore being exhausted. If, as is often the case in humid districts, the soil is saturated, that is, the film is as thick as theparticles can hold, the water would pass right through the soil andconnect with the standing water below. This, of course, is seldomthe case in dry-farm districts. In any soil, excepting one alreadysaturated, the addition of water will produce a thickening of thesoil-water film to the full descent of the water. This immediatelydestroys the conditions of equilibrium formerly existing, for themoisture is not now uniformly distributed. Consequently a process ofredistribution begins which continues until the nearest approach toequilibrium is restored. In this process water will pass in everydirection from the wet portion of the soil to the drier; it does notnecessarily mean that water will actually pass from the wet portionto the drier portion; usually, at the driest point a little water isdrawn from the adjoining point, which in turn draws from the next, and that from the next, until the redistribution is complete. Theprocess is very much like stuffing wool into a sack which already isloosely filled. The new wool does not reach the bottom of the sack, yet there is more wool in the bottom than there was before. 

If a plant-root is actively feeding some distance under the soilsurface, the reverse process occurs. At the feeding point the rootcontinually abstracts water from the soil grains and thus makes thefilm thinner in that locality. This causes a movement of moisturesimilar to the one above described, from the wetter portions of thesoil to the portion being dried out by the action of the plant-root. Soil many feet or even rods distant may assist in supplying such anactive root with moisture. When the thousands of tiny roots sent outby each plant are recalled. It may well be understood what aconfusion of pulls and counter-pulls upon the soil-moisture existsin any cultivated soil. In fact, the soil-water film may be viewedas being in a state of trembling activity, tending to place itselfin full equilibrium with the surrounding contending forces which, themselves, constantly change. Were it not that the water film heldclosely around the soil particles is possessed of extreme mobility, it would not be possible to meet the demands of the plants upon thewater at comparatively great distances. Even as it is, it frequentlyhappens that when crops are planted too thickly on dry-farms, thesoil-moisture cannot move quickly enough to the absorbing roots tomaintain plant growth, and crop failure results. Incidentally, thispoints to planting that shall be proportional to the moisturecontained by the soil. See Chapter XI. 

As the temperature rises in spring, with a decrease in the relativehumidity, and an increase in direct sunshine, evaporation from thesoil surface increases greatly. However, as the topsoil becomesdrier, that is, as the water fihn becomes thinner, there is anattempt at readjustment, and water moves upward to take the place ofthat lost by evaporation. As this continues throughout the season, the moisture stored eight or ten feet or more below the surface isgradually brought to the top and evaporated, and thus lost to plantuse. 

The effect of rapid top drying of soils

As the water held by soils diminishes, and the water film around thesoil grains becomes thinner, the capillary movement of thesoil-water is retarded. This is easily understood by recalling thatthe soil particles have an attraction for water, which is ofdefinite value, and may be measured by the thickest film that may beheld against gravity. When the film is thinned, it does not diminishthe attraction of the soil for water; it simply results in astronger pull upon the water and a firmer holding of the filmagainst the surfaces of the soil grains. To move soil-water undersuch conditions requires the expenditure of more energy than isnecessary for moving water in a saturated or nearly saturated soil. Under like conditions, therefore, the thinner the soil-water filmthe more difficult will be the upward movement of the soil-water andthe slower the evaporation from the topsoil. 

As drying goes on, a point is reached at which the capillarymovement of the water wholly ceases. This is probably when littlemore than the hygroscopic moisture remains. In fact, very dry soiland water repel each other. This is shown in the common experienceof driving along a road in summer, immediately after a light shower. The masses of dust are wetted only on the outside, and as the wheelspass through them the dry dust is revealed. It is an important factthat very dry soil furnishes a very effective protection against thecapillary movement of water. 

In accordance with the principle above established if the surfacesoil could be dried to the point where capillarity is very slow, theevaporation would be diminished or almost wholly stopped. More thana quarter of a century ago, Eser showed experimentally thatsoil-water may be saved by drying the surface soil rapidly. Underdry-farm conditions it frequently occurs that the draft upon thewater of the soil is so great that nearly all the water is quicklyand so completely abstracted from the upper few inches of soil thatthey are left as an effective protection against furtherevaporation. For instance, in localities where hot dry winds are ofcommon occurrence, the upper layer of soil is sometimes completelydried before the water in the lower layers can by slow capillarymovement reach the top. The dry soil layer then prevents furtherloss of water, and the wind because of its intensity has helped toconserve the soil-moisture. Similarly in localities where therelative humidity is low, the sunshine abundant, and the temperaturehigh, evaporation may go on so rapidly that the lower soil layerscannot supply the demands made, and the topsoil then dries out socompletely as to form a protective covering against furtherevaporation. It is on this principle that the native desert soils ofthe United States, untouched by the plow, and the surfaces of whichare sun-baked, are often found to possess large percentages of waterat lower depths. Whitney recorded this observation with considerablesurprise, many years ago, and other observers have found the sameconditions at nearly all points of the arid region. This matter hasbeen subjected to further study by Buckingham, who placed a varietyof soils under artificially arid and humid conditions. It was foundin every case that, the initial evaporation was greater under aridconditions, but as the process went on and the topsoil of the aridsoil became dry, more water was lost under humid conditions. For thewhole experimental period, also, more water was lost under humidconditions. It was notable that the dry protective layer was formedmore slowly on alkali soils, which would point to the inadvisabilityof using alkali lands for dry-farm purposes. All in all, however, itappears "that under very arid conditions a soil automaticallyprotects itself from drying by the formation of a natural mulch onthe surface. "

Naturally, dry-farm soils differ greatly in their power of formingsuch a mulch. A heavy clay or a light sandy soil appears to haveless power of such automatic protection than a loamy soil. Anadmixture of limestone seems to favor the formation of such anatural protective mulch. Ordinarily, the farmer can further theformation of a dry topsoil layer by stirring the soil thoroughly. This assists the sunshine and the air to evaporate the water veryquickly. Such cultivation is very desirable for other reasons also, as will soon be discussed. Meanwhile, the water-dissipating forcesof the dry-farm section are not wholly objectionable, for whetherthe land be cultivated or not, they tend to hasten the formation ofdry surface layers of soil which guard against excessiveevaporation. It is in moist cloudy weather, when the drying processis slow, that evaporation causes the greatest losses ofsoil-moisture. 

The effect of shading

Direct sunshine is, next to temperature, the most active cause ofrapid evaporation from moist soil surfaces. Whenever, therefore, evaporation is not rapid enough to form a dry protective layer oftopsoil, shading helps materially in reducing surface losses ofsoil-water. Under very arid conditions, however, it is questionablewhether in all cases shading has a really beneficial effect, thoughunder semiarid or sub-humid conditions the benefits derived fromshading are increased largely. Ebermayer showed in 1873 that theshading due to the forest cover reduced evaporation 62 per cent, andmany experiments since that day have confirmed this conclusion. Atthe Utah Station, under arid conditions, it was found that shading apot of soil, which otherwise was subjected to water-dissipatinginfluences, saved 29 per cent of the loss due to evaporation from apot which was not shaded. This principle cannot be applied verygreatly in practice, but it points to a somewhat thick planting, proportioned to the water held by the soil. It also shows a possiblebenefit to be derived from the high header straw which is allowed tostand for several weeks in dry-farm sections where the harvest comesearly and the fall plowing is done late, as in the mountain states. The high header stubble shades the ground very thoroughly. Thus thestubble may be made to conserve the soil-moisture in dry-farmsections, where grain is harvested by the "header" method. 

A special case of shading is the mulching of land with straw orother barnyard litter, or with leaves, as in the forest. Suchmulching reduces evaporation, but only in part, because of itsshading action, since it acts also as a loose top layer of soilmatter breaking communication with the lower soil layers. 

Whenever the soil is carefully stirred, as will be described, thevalue of shading as a means or checking evaporation disappearsalmost entirely. It is only with soils which are tolerably moist atthe surface that shading acts beneficially. 

Alfalfa in cultivated rows. This practice is employed to makepossible the growth of alfalfa and other perennial crops on aridlands without irrigation. 

The effect of tillage

Capillary soil-moisture moves from particle to particle until thesurface is reached. The closer the soil grains are packed together, the greater the number of points or contact, and the more easilywill the movement of the soil-moisture proceed. If by any means alayer of the soil is so loosened as to reduce the number of pointsof contact, the movement of the soil-moisture is correspondinglyhindered. The process is somewhat similar to the experience in larger airway stations. Just before train time a great crowd of people isgathered outside or the gates ready to show their tickets. If onegate is opened, a certain number of passengers can pass through eachminute; if two are opened, nearly twice as many may be admitted inthe same time; if more gates are opened, the passengers will be ableto enter the train more rapidly. The water in the lower layers ofthe soil is ready to move upward whenever a call is made upon it. Toreach the surface it must pass from soil grain to soil grain, andthe larger the number of grains that touch, the more quickly andeasily will the water reach the surface, for the points of contactof the soil particles may be likened to the gates of the railwaystation. Now if, by a thorough stirring and loosening of thetopsoil, the number of points of contact between the top and subsoilis greatly reduced, the upward flow of water is thereby largelychecked. Such a loosening of the topsoil for the purpose of reducingevaporation from the topsoil has come to be called cultivation, andincludes plowing, harrowing, disking, hoeing, and other culturaloperations by which the topsoil is stirred. The breaking of thepoints of contact between the top and subsoil is undoubtedly themain reason for the efficiency of cultivation, but it is also to beremembered that such stirring helps to dry the top soil verythoroughly, and as has been explained a layer of dry soil of itselfis a very effective check upon surface evaporation. 

That the stirring or cultivation of the topsoil really does diminishevaporation of water from the soil has been shown by numerousinvestigations. In 1868, Nessler found that during six weeks of anordinary German summer a stirred soil lost 510 grams of water persquare foot, while the adjoining compacted soil lost 1680 grams, --asaving due to cultivation of nearly 60 per cent. Wagner, testing thecorrectness of Nessler's work, found, in 1874, that cultivationreduced the evaporation a little more than 60 per cent; Johnson, in1878, confirmed the truth of the principle on American soils, andLevi Stockbridge, working about the same time, also on Americansoils, found that cultivation diminished evaporation on a clay soilabout 23 per cent, on a sandy loam 55 per cent, and on a heavy loamnearly 13 per cent. All the early work done on this subject was doneunder humid conditions, and it is only in recent years thatconfirmation of this important principle has been obtained for thesoils of the dry-farm region. Fortier, working under Californiaconditions, determined that cultivation reduced the evaporation fromthe soil surface over 55 per cent. At the Utah Station similarexperiments have shown that the saving of soil-moisture bycultivation was 63 per cent for a clay soil, 34 per cent for acoarse sand, and 13 per cent for a clay loam. Further, practicalexperience has demonstrated time and time again that in cultivationthe dry-farmer has a powerful means of preventing evaporation fromagricultural soils. 

Closely connected with cultivation is the practice of scatteringstraw or other litter over the ground. Such artificial mulches arevery effective in reducing evaporation. Ebermayer found that byspreading straw on the land, the evaporation was reduced 22 percent; Wagner found under similar conditions a saving of 38 per cent, and these results have been confirmed by many other investigators. On the modern dry-farms, which are large in area, the artificialmulching of soils cannot become a very extensive practice, yet it iswell to bear the principle in mind. The practice of harvestingdry-farm grain with the header and plowing under the high stubble inthe fall is a phase of cultivation for water conservation thatdeserves special notice. The straw, thus incorporated into the soil, decomposes quite readily in spite of the popular notion to thecontrary, and makes the soil more porous, and, therefore, moreeffectively worked for the prevention of evaporation. When thispractice is continued for considerable periods, the topsoil becomesrich in organic matter, which assists in retarding evaporation, besides increasing the fertility of the land. When straw cannot befed to advantage, as is yet the case on many of the westerndry-farms, it would be better to scatter it over the land than toburn it, as is often done. Anything that covers the ground orloosens the topsoil prevents in a measure the evaporation of thewater stored in lower soil depths for the use of crops. 

Depth of cultivation

The all-important practice for the dry-farmer who is entering uponthe growing season is cultivation. The soil must be coveredcontinually with a deep layer of dry loose soil, which because ofits looseness and dryness makes evaporation difficult. A leadingquestion in connection with cultivation is the depth to which thesoil should be stirred for the best results. Many of the earlystudents of the subject found that a soil mulch only one half inchin depth was effective in retaining a large part of thesoil-moisture which noncultivated soils would lose by evaporation. Soils differ greatly in the rate of evaporation from their surfaces. Some form a natural mulch when dried, which prevents further waterloss. Others form only a thin hard crust, below which lies an activeevaporating surface of wet soil. Soils which dry out readily andcrumble on top into a natural mulch should be cultivated deeply, fora shallow cultivation does not extend beyond the naturally formedmulch. In fact, on certain calcareous soils, the surfaces of whichdry out quickly and form a good protection against evaporation, shallow cultivations often cause a greater evaporation by disturbingthe almost perfect natural mulch. Clay or sand soils, which do notso well form a natural mulch, will respond much better to shallowcultivations. In general, however, the deeper the cultivation, themore effective it is in reducing evaporation. Fortier, in theexperiments in California to which allusion has already been made, showed the greater value of deep cultivation. During a period offifteen days, beginning immediately after an irrigation, the soilwhich had not been mulched lost by evaporation nearly one fourth ofthe total amount of water that had been added. A mulch 4 inches deepsaved about 72 per cent of the evaporation; a mulch 8 inches deepsaved about 88 per cent, and a mulch 10 inches deep stoppedevaporation almost wholly. It is a most serious mistake for thedry-farmer, who attempts cultivation for soil-moisture conservation, to fail to get the best results simply to save a few cents per acrein added labor. 

When to cultivate or till

It has already been shown that the rate of evaporation is greaterfrom a wet than from a dry surface. It follows, therefore, that thecritical time for preventing evaporation is when the soil iswettest. After the soil is tolerably dry, a very large portion ofthe soil-moisture has been lost, which possibly might have beensaved by earlier cultivation. The truth of this statement is wellshown by experiments conducted by the Utah Station. In one case on asoil well filled with water, during a three weeks' period, nearlyone half of the total loss occurred the first, while only one fifthfell on the third week. Of the amount lost during the first week, over 60 per cent occurred during the first three days. Cultivationshould, therefore, be practiced as soon as possible after conditionsfavorable for evaporation have been established. This means, first, that in early spring, just as soon as the land is dry enough to beworked without causing puddling, the soil should be deeply andthoroughly stirred. Spring plowing, done as early as possible, is anexcellent practice for forming a mulch against evaporation. Evenwhen the land has been fall-plowed, spring plowing is verybeneficial, though on fall-plowed land the disk harrow is usuallyused in early spring, and if it is set at rather a sharp angle, andproperly weighted, so that it cuts deeply into the ground, it ispractically as effective as spring plowing. The chief danger to thedry-farmer is that he will permit the early spring days to slip byuntil, when at last he begins spring cultivation, a large portion ofthe stored soil-water has been evaporated. It may be said that deepfall plowing, by permitting the moisture to sink quickly into thelower layers of soil, makes it possible to get upon the groundearlier in the spring. In fact, unplowed land cannot be cultivatedas early as that which has gone through the winter in a plowedcondition

If the land carries a fall-sown crop, early spring cultivation isdoubly important. As soon as the plants are well up in spring theland should be gone over thoroughly several times if necessary, withan iron tooth harrow, the teeth of which are set to slant backwardin order not to tear up the plants. The loose earth mulch thusformed is very effective in conserving moisture; and the few plantstorn up are more than paid for by the increased water supply for theremaining plants. The wise dry-fanner cultivates his land, whetherfallow or cropped, as early as possible in the spring. 

Following the first spring plowing, disking, or cultivation, mustcome more cultivation. Soon after the spring plowing, the landshould be disked and. Then harrowed. Every device should be used tosecure the formation of a layer of loose drying soil over the landsurface. The season's crop will depend largely upon theeffectiveness of this spring treatment. 

As the season advances, three causes combine to permit theevaporation of soil-moisture. 

First, there is a natural tendency, under the somewhat moistconditions of spring, for the soil to settle compactly and thus torestore the numerous capillary connections with the lower soillayers through which water escapes. Careful watch should thereforebe kept upon the soil surface, and whenever the mulch is not loose, the disk or harrow should be run over the land. 

Secondly, every rain of spring or summer tends to establishconnections with the store of moisture in the soil. In fact, latespring and summer rains are often a disadvantage on dry-farms, whichby cultural treatment have been made to contain a large store ofmoisture. It has been shown repeatedly that light rains drawmoisture very quickly from soil layers many feet below the surface. The rainless summer is not feared by the dry-farmer whose soils arefertile and rich in moisture. It is imperative that at the veryearliest moment after a spring or summer rain the topsoil be wellstirred to prevent evaporation. It thus happens that in sections offrequent summer rains, as in the Great Plains area, the farmer hasto harrow his land many times in succession, but the increased cropyields invariably justify the added expenditure of effort. 

Thirdly, on the summer-fallowed ground weeds start vigorously in thespring and draw upon the soil-moisture, if allowed to grow, fully asheavily as a crop of wheat or corn. The dry-farmer must not allow aweed upon his land. Cultivation must he so continuous as to makeweeds an impossibility. The belief that the elements added to thesoil by weeds offset the loss of soil-moisture is wholly erroneous. The growth of weeds on a fallow dry-farm is more dangerous than thepacked uncared-for topsoil. Many implements have been devised forthe easy killing of weeds, but none appear to be better than theplow and the disk which are found on every farm. (See Chapter XV. )

When crops are growing on the land, thorough summer cultivation issomewhat more difficult, but must be practiced for the greatestcertainty of crop yields. Potatoes, corn, and similar crops may becultivated with comparative ease, by the use of ordinarycultivators. With wheat and the other small grains, generally, thedamage done to the crop by harrowing late in the season is toogreat, and reliance is therefore placed on the shading power of theplants to prevent undue evaporation. However, until the wheat andother grains are ten to twelve inches high, it is perfectly safe toharrow them. The teeth should be set backward to diminish thetearing up of the plants, and the implement weighted enough to breakthe soil crust thoroughly. This practice has been fully tried outover the larger part of the dry-farm territory and foundsatisfactory. 

So vitally important is a permanent soil mulch for the conservationfor plant use of the water stored in the soil that many attemptshave been made to devise means for the effective cultivation of landon which small grains and grasses are growing. In many places plantshave been grown in rows so far apart that a man with a hoe couldpass between them. Scofield has described this method as practicedsuccessfully in Tunis. Campbell and others in America have proposedthat a drill hole be closed every three feet to form a path wideenough for a horse to travel in and to pull a large spring toothcultivator' with teeth so spaced as to strike between the rows ofwheat. It is yet doubtful whether, under average conditions, suchcareful cultivation, at least of grain crops, is justified by thereturns. Under conditions of high aridity, or where the store ofsoil-moisture is low, such treatment frequently stands between cropsuccess and failure, and it is not unlikely that methods will bedevised which will permit of the cheap and rapid cultivation betweenthe rows of growing wheat. Meanwhile, the dry-farmer must alwaysremember that the margin under which he works is small, and that hissuccess depends upon the degree to which he prevents small wastes. 

Dry-farm potatoes, Rosebud Co. , Montana, 1909. Yield, 282 bushelsper acre. 

The conservation of soil-moisture depends upon the vigorous, unremitting, continuous stirring of the topsoil. Cultivation!cultivation! and more cultivation! must be the war-cry of thedry-farmer who battles against the water thieves of an arid climate. 

CHAPTER IX

REGULATING THE TRANSPIRATION

Water that has entered the soil may be lost in three ways. First, itmay escape by downward seepage, whereby it passes beyond the reachof plant roots and often reaches the standing water. In dry-farmdistricts such loss is a rare occurrence, for the naturalprecipitation is not sufficiently large to connect with the countrydrainage, and it may, therefore, be eliminated from consideration. Second, soil-water may be lost by direct evaporation from thesurface soil. The conditions prevailing in arid districts favorstrongly this manner of loss of soil-moisture. It has been shown, however, in the preceding chapter that the farmer, by proper andpersistent cultivation of the topsoil, has it in his power to reducethis loss enough to be almost negligible in the farmer'sconsideration. Third, soil-water may be lost by evaporation from theplants themselves. While it is not generally understood, this sourceof loss is, in districts where dry-farming is properly carried on, very much larger than that resulting either from seepage or fromdirect evaporation. While plants are growing, evaporation fromplants, ordinarily called transpiration, continues. Experimentsperformed in various arid districts have shown that one and a halfto three times more water evaporates from the plant than directlyfrom well-tilled soil. To the present very little has been learnedconcerning the most effective methods of checking or controllingthis continual loss of water. Transpiration, or the evaporation ofwater from the plants themselves and the means of controlling thisloss, are subjects of the deepest importance to the dry-farmer. 

Absorption

To understand the methods for reducing transpiration, as proposed inthis chapter, it is necessary to review briefly the manner in whichplants take water from the soil. The roots are the organs of waterabsorption. Practically no water is taken into the plants by thestems or leaves, even under conditions of heavy rainfall. Such smallquantities as may enter the plant through the stems and leaves areof very little value in furthering the life and growth of the plant. The roots alone are of real consequence in water absorption. Allparts of the roots do not possess equal power of taking upsoil-water. In the process of water absorption the younger roots aremost active and effective. Even of the young roots, however, onlycertain parts are actively engaged in water absorption. At the verytips of the young growing roots are numerous fine hairs. Theseroot-hairs, which cluster about the growing point of the youngroots, are the organs of the plant that absorb soil-water. They areof value only for limited periods of time, for as they grow older, they lose their power of water absorption. In fact, they are activeonly when they are in actual process of growth. It follows, therefore, that water absorption occurs near the tips of the growingroots, and whenever a plant ceases to grow the water absorptionceases also. The root-hairs are filled with a dilute solution ofvarious substances, as yet poorly understood, which plays animportant tent part in the ab sorption of water and plant-food fromthe soil. 

Owing to their minuteness, the root-hairs are in most cases immersedin the water film that surrounds the soil particles, and thesoil-water is taken directly into the roots from the soil-water filmby the process known as osmosis. The explanation of this inwardmovement is complicated and need not be discussed here. It issufficient to say that the concentration or strength of the solutionwithin the root-hair is of different degree from the soil-watersolution. The water tends, therefore, to move from the soil into theroot, in order to make the solutions inside and outside of the rootof the same concentration. If it should ever occur that thesoil-water and the water within the root-hair became the sameconcentration, that is to say, contained the same substances in thesame proportional amounts, there would be no further inward movementof water. Moreover, if it should happen that the soil-water isstronger than the water within the root-hair, the water would tendto pass from the plant into the soil. This is the condition thatprevails in many alkali lands of the West, and is the cause of thedeath of plants growing on such lands. 

It is clear that under these circumstances not only water enters theroot-hairs, but many of the substances found in solution in thesoil-water enter the plant also. Among these are the mineralsubstances which are indispensable for the proper life and growth ofplants. These plant nutrients are so indispensable that if any oneof them is absent, it is absolutely impossible for the plant tocontinue its life functions. The indispensable plant-foods gatheredfrom the soil by the root-hairs, in addition to water, are:potassium, calcium, magnesium, iron, nitrogen, and phosphorus, --allin their proper combinations. How the plant uses these substances isyet poorly understood, but we are fairly certain that each one hassome particular function in the life of the plant. For instance, nitrogen and phosphorus are probably necessary in the formation ofthe protein or the flesh-forming portions of the plant, while potashis especially valuable in the formation of starch. 

There is a constant movement of the indispensable plant nutrientsafter they have entered the root-hairs, through the stems and intothe leaves. This constant movement of the plant-foods depends uponthe fact that the plant consumes in its growth considerablequantities of these substances, and as the plant juices arediminished in their content of particular plant-foods, more entersfrom the soil solution. The necessary plant-foods do not alone enterthe plant but whatever may be in solution in the soil-water entersthe plant in variable quantities. Nevertheless, since the plant usesonly a few definite substances and leaves the unnecessary ones insolution, there is soon a cessation of the inward movement of theunimportant constituents of the soil solution. This process is oftenspoken of as selective absorption; that is, the plant, because ofits vital activity, appears to have the power of selecting from thesoil certain substances and rejecting others. 

Movement of water through plant

The soil-water, holding in solution a great variety of plantnutrients, passes from the root-hairs into the adjoining cells andgradually moves from cell to cell throughout the whole plant. Inmany plants this stream of water does not simply pass from cell tocell, but moves through tubes that apparently have been formed forthe specific purpose of aiding the movement of water through theplant. The rapidity of this current is often considerable. Ordinarily, it varies from one foot to six feet per hour, thoughobservations are on record showing that the movement often reachesthe rate of eighteen feet per hour. It is evident, then, that in anactively growing plant it does not take long for the water which isin the soil to find its way to the uppermost parts of the plant. 

The work of leaves

Whether water passes upward from cell to cell or through especiallyprovided tubes, it reaches at last the leaves, where evaporationtakes place. It is necessary to consider in greater detail whattakes place in leaves in order that we may more clearly understandthe loss due to transpiration. One half or more of every plant ismade up of the element carbon. The remainder of the plant consistsof the mineral substances taken from the soil (not more than two to10 per cent of the dry plant) and water which has been combined withthe carbon and these mineral substances to form the characteristicproducts of plant life. The carbon which forms over half of theplant substance is gathered from the air by the leaves and it isevident that the leaves are very active agents of plant growth. Theatmosphere consists chiefly of the gases oxygen and nitrogen in theproportion of one to four, but associated with them are smallquantities of various other substances. Chief among the secondaryconstituents of the atmosphere is the gas carbon dioxid, which isformed when carbon burns, that is, when carbon unites with theoxygen of the air. Whenever coal or wood or any carbonaceoussubstance burns, carbon dioxid is formed. Leaves have the power ofabsorbing the gas carbon dioxid from the air and separating thecarbon from the oxygen. The oxygen is returned to the atmospherewhile the carbon is retained to be used as the fundamental substancein the construction by the plant of oils, fats, starches, sugars, protein, and all the other products of plant growth. 

This important process known as carbon assimilation is made possibleby the aid of countless small openings which exist chicfly on thesurfaces of leaves and known as "stomata. " The stomata aredelicately balanced valves, exceedingly sensitive to externalinfluences. They are more numerous on the lower side than on theupper side of plants. In fact, there is often five times more on theunder side than on the upper side of a leaf. It has been estimatedthat 150, 000 stomata or more are often found per square inch on theunder side of the leaves of ordinary cultivated plants. The stomataor breathing-pores are so constructed that they may open and closevery readily. In wilted leaves they are practically closed; oftenthey also close immediately after a rain; but in strong sunlightthey are usually wide open. It is through the stomata that the gasesof the air enter the plant through which the discarded oxygenreturns to the atmosphere. 

It is also through the stomata that the water which is drawn fromthe soil by the roots through the stems is evaporated into the air. There is some evaporation of water from the stems and branches ofplants, but it is seldom more than a thirtieth or a fortieth of thetotal transpiration. The evaporation of water from the leavesthrough the breathing-pores is the so-called transpiration, which isthe greatest cause of the loss of soil-water under dry-farmconditions. It is to the prevention of this transpiration that muchinvestigation must be given by future students of dry-farming. 

Transpiration

As water evaporates through the breathing-pores from the leaves itnecessarily follows that a demand is made upon the lower portions ofthe plant for more water. The effect of the loss of water is feltthroughout the whole plant and is, undoubtedly, one of the chiefcauses of the absorption of water from the soil. As evaporation isdiminished the amount of water that enters the plants is alsodiminished. Yet transpiration appears to be a process whollynecessary for plant life. The question is, simply, to what extent itmay be diminished without injuring plant growth. Many studentsbelieve that the carbon assimilation of the plant, which isfundamentally important in plant growth, cannot be continued unlessthere is a steady stream of water passing through the plant and thenevaporating from the leaves. 

Of one thing we are fairly sure: if the upward stream of water iswholly stopped for even a few hours, the plant is likely to be soseverely injured as to be greatly handicapped in its future growth. 

Botanical authorities agree that transpiration is of value to plantgrowth, first, because it helps to distribute the mineral nutrientsnecessary for plant growth uniformly throughout the plant; secondly, because it permits an active assimilation of the carbon by theleaves; thirdly, because it is not unlikely that the heat requiredto evaporate water, in large part taken from the plant itself, prevents the plant from being overheated. This last mentioned valueof transpiration is especially important in dry-farm districts, where, during the summer, the heat is often intense. Fourthly, transpiration apparently influences plant growth and development ina number of ways not yet clearly understood. 

Conditions influencing transpiration

In general, the conditions that determine the evaporation of waterfrom the leaves are the same as those that favor the directevaporation of water from soils, although there seems to besomething in the life process of the plant, a physiological factor, which permits or prevents the ordinary water-dissipating factorsfrom exercising their full powers. That the evaporation of waterfrom the soil or from a free water surface is not the same as thatfrom plant leaves may be shown in a general way from the fact thatthe amount of water transpired from a given area of leaf surface maybe very much larger or very much smaller than that evaporated froman equal surface of free water exposed to the same conditions. It isfurther shown by the fact that whereas evaporation from a free watersurface goes on with little or no interruption throughout thetwenty-four hours of the day, transpiration is virtually at astandstill at night even though the conditions for the rapidevaporation from a free water surface are present. 

Some of the conditions influencing the transpiration may beenumerated as follows:--

First, transpiration is influenced by the relative humidity. In dryair, under otherwise similar conditions, plants transpire more waterthan in moist air though it is to be noted that even when theatmosphere is fully saturated, so that no water evaporates from afree water surface, the transpiration of plants still continues in asmall degree. This is explained by the observation that since thelife process of a plant produces a certain amount of heat, the plantis always warmer than the surrounding air and that transpirationinto an atmosphere fully charged with water vapor is consequentlymade possible. The fact that transpiration is greater under a lowrelative humidity is of greatest importance to the dry-farmer whohas to contend with the dry atmosphere. 

Second, transpiration increases with the increase in temperature;that is, under conditions otherwise the same, transpiration is morerapid on a warm day than on a cold one. The temperature increase ofitself, however, is not sufficient to cause transpiration. 

Third, transpiration increases with the increase of air currents, which is to say, that on a windy day transpiration is much morerapid than on a quiet day. 

Fourth, transpiration increases with the increase of directsunlight. It is an interesting observation that even with the samerelative humidity, temperature, and wind, transpiration is reducedto a minimum during the night and increases manyfold during the daywhen direct sunlight is available. This condition is again to benoted by the dry-farmer, for the dry-farm districts arecharacterized by an abundance of sunshine. 

Fifth, transpiration is decreased by the presence in the soil-waterof large quantities of the substances which the plant needs for itsfood material. This will be discussed more fully in the nextsection. 

Sixth, any mechanical vibration of the plant seems to have someeffect upon the transpiration. At times it is increased and at timesit is decreased by such mechanical disturbance. 

Seventh, transpiration varies also with the age of the plant. In theyoung plant it is comparatively small. Just before blooming it isvery much larger and in time of bloom it is the largest in thehistory of the plant. As the plant grows older transpirationdiminishes, and finally at the ripening stage it almost ceases. 

Eighth, transpiration varies greatly with the crop. Not all plantstake water from the soil at the same rate. Very little is as yetknown about the relative water requirements of crops on the basis oftranspiration. As an illustration, MacDougall has reported thatsagebrush uses about one fourth as much water as a tomato plant. Even greater differences exist between other plants. This is one ofthe interesting subjects yet to be investigated by those who areengaged in the reclamation of dry-farm districts. Moreover, the samecrop grown under different conditions varies in its rate oftranspiration. For instance, plants grown for some time under aridconditions greatly modify their rate of transpiration, as shown bySpalding, who reports that a plant reared under humid conditionsgave off 3. 7 times as much water as the same plant reared under aridconditions. This very interesting observation tends to confirm theview commonly held that plants grown under arid conditions willgradually adapt themselves to the prevailing conditions, and inspite of the greater water dissipating conditions will live with theexpenditure of less water than would be the case under humidconditions. Further, Sorauer found, many years ago, that differentvarieties of the same crop possess very different rates oftranspiration. This also is an interesting subject that should bemore fully investigated in the future. 

Ninth, the vigor of growth of a crop appears to have a stronginfluence on transpiration. It does not follow, however, that themore vigorously a crop grows, the more rapidly does it transpirewater, for it is well known that the most luxuriant plant growthoccurs in the tropics, where the transpiration is exceedingly low. It seems to be true that under the same conditions, plants that growmost vigorously tend to use proportionately the smallest amount ofwater. 

Tenth, the root system--its depth and manner of growth--influencesthe rate of transpiration. The more vigorous and extensive the rootsystem, the more rapidly can water be secured from the soil by theplant. 

The conditions above enumerated as influencing transpiration arenearly all of a physical character, and it must not be forgottenthat they may all be annulled or changed by a physiologicalregulation. It must be admitted that the subject of transpiration isyet poorly understood, though it is one of the most importantsubjects in its applications to plant production in localities wherewater is scaree. It should also be noted that nearly all of theabove conditions influencing transpiration are beyond the control ofthe farmer. The one that seems most readily controlled in ordinaryagricultural practice will be discussed in the following section. 

Plant-food and transpiration

It has been observed repeatedly by students of transpiration thatthe amount of water which actually evaporates from the leaves isvaried materially by the substances held in solution by thesoil-water. That is, transpiration depends upon the nature andconcentration of soil solution. This fact, though not commonlyapplied even at the present time, has really been known for a verylong time. Woodward, in 1699, observed that the amount of watertranspired by a plant growing in rain water was 192. 3 grams; inspring water, 163. 6 grams, and in water from the River Thames, 159. 5grams; that is, the amount of water transpired by the plant in thecomparatively pure rain water was nearly 20 per cent higher thanthat used by the plant growing in the notoriously impure water ofthe River Thames. Sachs, in 1859, carried on an elaborate series ofexperiments on transpiration in which he showed that the addition ofpotassium nitrate, ammonium sulphate or common salt to the solutionin which plants grew reduced the transpiration; in fact, thereduction was large, varying from 10 to 75 per cent. This wasconfirmed by a number of later workers, among them, for instance, Buergerstein, who, in 1875, showed that whenever acids were added toa soil or to water in which plants are growing, the transpiration isincreased greatly; but when alkalies of any kind are added, transpiration decreases. This is of special interest in thedevelopment of dry-farming, since dry-farm soils, as a rule, containmore substances that may be classed as alkalies than do soilsmaintained under humid conditions. Sour soils are verycharacteristic of districts where the rainfall is abundant; thevegetation growing on such soils transpires excessively and thecrops are consequently more subject to drouth. 

The investigators of almost a generation ago also determined beyondquestion that whenever a complete nutrient solution is presented toplants, that is, a solution containing all the necessary plant-foodsin the proper proportions, the transpiration is reduced immensely. It is not necessary that the plant-foods should be presented in awater solution in order to effect this reduction in transpiration;if they are added to the soil on which plants are growing, the sameeffect will result. The addition of commercial fertilizers to thesoil will therefore diminish transpiration. It was furtherdiscovered nearly half a century ago that similar plants growing ondifferent soils evaporate different amounts of water from theirleaves; this difference, undoubtedly, is due to the conditions inthe fertility of the soils, for the more fertile a soil is, thericher will the soil-water be in the necessary plant-foods. Theprinciple that transpiration or the evaporation of water from theplants depends on the nature and concentration of the soil solutionis of far-reaching importance in the development of a rationalpractice of dry-farming. 

Transpiration for a pound of dry matter

Is plant growth proportional to transpiration? Do plants thatevaporate much water grow more rapidly than those that evaporateless? These questions arose very early in the period characterizedby an active study of transpiration. If varying the transpirationvaries the growth, there would be no special advantage in reducingthe transpiration. From an economic point of view the importantquestion is this: Does the plant when its rate of transpiration isreduced still grow with the same vigor? If that be the case, thenevery effort should be made by the farmer to control and to diminishthe rate of transpiration. 

One of the very earliest experiments on transpiration, conducted byWoodward in 1699, showed that it required less water to produce apound of dry matter if the soil solution were of the properconcentration and contained the elements necessary for plant growth. Little more was done to answer the above questions for over onehundred and fifty years. Perhaps the question was not even askedduring this period, for scientific agriculture was just coming intobeing in countries where the rainfall was abundant. However, Tschaplowitz, in 1878, investigated the subject and found that theincrease in dry matter is greatest when the transpiration is thesmallest. Sorauer, in researches conducted from 1880 to 1882, determined with almost absolute certainty that less water isrequired to produce a pound of dry matter when the soil isfertilized than when it is not fertilized. Moreover, he observedthat the enriching of the soil solution by the addition ofartificial fertilizers enabled the plant to produce dry matter withless water. He further found that if a soil is properly tilled so asto set free plant-food and in that way to enrich the soil solutionthe water-cost of dry plant substance is decreased. Hellriegel, in1883, confirmed this law and laid down the law that poor plantnutrition increases the water-cost of every pound of dry matterproduced. It was about this time that the Rothamsted ExperimentStation reported that its experiments had shown that during periodsof drouth the well-tilled and well-fertilized fields yielded goodcrops, while the unfertilized fields yielded poor crops or cropfailures--indicating thereby, since rainfall was the criticalfactor, that the fertility of the soil is important in determiningwhether or not with a small amount of water a good crop can beproduced. Pagnoul, working in 1895 with fescue grass, arrived at thesame conclusion. On a poor clay soil it required 1109 pounds ofwater to produce one pound of dry matter, while on a rich calcareoussoil only 574 pounds were required. Gardner of the United StatesDepartment of Agriculture, Bureau of Soils, working in 1908, on themanuring of soils, came to the conclusion that the more fertile thesoil the less water is required to produce a pound of dry matter. Heincidentally called attention to the fact that in countries oflimited rainfall this might be a very important principle to applyin crop production. Hopkins in his study of the soils of Illinoishas repeatedly observed, in connection with certain soils, thatwhere the land is kept fertile, injury from drouth is not common, implying thereby that fertile soils will produce dry matter at alower water-cost. The most recent experiments on this subject, conducted by the Utah Station, confirm these conclusions. Theexperiments, which covered several years, were conducted in potsfilled with different soils. On a soil, naturally fertile, 908pounds of water were transpired for each pound of dry matter (corn)produced; by adding to this soil an ordinary dressing of manure'this was reduced to 613 pounds, and by adding a small amount ofsodium nitrate it was reduced to 585 pounds. If so large a reductioncould be secured in practice, it would seem to justify the use ofcommercial fertilizers in years when the dry-farm year opens withlittle water stored in the soil. Similar results, as will be shownbelow, were obtained by the use of various cultural methods. It maytherefore, be stated as a law, that any cultural treatment whichenables the soil-water to acquire larger quantities of plant-foodalso enables the plant to produce dry matter with the use of asmaller amount of water. In dry-farming, where the limiting factoris water, this principle must he emphasized in every culturaloperation. 

Methods of controlling transpiration

It would appear that at present the only means possessed by thefarmer for controlling transpiration and making possible maximumcrops with the minimum amount of water in a properly tilled soil isto keep the soil as fertile as is possible. In the light of thisprinciple the practices already recommended for the storing of waterand for the prevention of the direct evaporation of water from thesoil are again emphasized. Deep and frequent plowing, preferably inthe fall so that the weathering of the winter may be felt deeply andstrongly, is of first importance in liberating plant-food. Cultivation which has been recommended for the prevention of thedirect evaporation of water is of itself an effective factor insetting free plant-food and thus in reducing the amount of waterrequired by plants. The experiments at the Utah Station, alreadyreferred to, bring out very strikingly the value of cultivation inreducing the transpiration. For instance, in a series of experimentsthe following results were obtained. On a sandy loam, notcultivated, 603 pounds of water were transpired to produce one poundof dry matter of corn; on the same soil, cultivated, only 252 poundswere required. On a clay loam, not cultivated, 535 pounds of waterwere transpired for each pound of dry matter, whereas on thecultivated soil only 428 pounds were necessary. On a clay soil, notcultivated, 753 pounds of water were transpired for each pound ofdry matter; on the cultivated soil, only 582 pounds. The farmer whofaithfully cultivates the soil throughout the summer and after everyrain has therefore the satisfaction of knowing that he isaccomplishing two very important things: he is keeping the moisturein the soil, and he is making it possible for good crops to be grownwith much less water than would otherwise be required. Even in thecase of a peculiar soil on which ordinary cultivation did not reducethe direct evaporation, the effect upon the transpiration was verymarked. On the soil which was not cultivated, 451 pounds of waterwere required to produce one pound of dry matter (corn), while onthe cultivated soils, though the direct evaporation was no smaller, the number of pounds of water for each pound of dry substance was aslow as 265. 

One of the chief values of fallowing lies in the liberation of theplant-food during the fallow year, which reduces the quantity ofwater required the next year for the full growth of crops. The Utahexperiments to which reference has already been made show the effectof the previous soil treatment upon the water requirements of crops. One half of the three types of soil had been cropped for threesuccessive years, while the other half had been left bare. Duringthe fourth year both halves were planted to corn. For the sandy loamit was found that, on the part that had been cropped previously, 659pounds of water were required for each pound of dry matter produced, while on the part that had been bare only 573 pounds were required. For the clay loam 889 pounds on the cropped part and 550 on thepreviously bare part were required for each pound of dry matter. Forthe clay 7466 pounds on the cropped part and 1739 pounds on thepreviously bare part were required for each pound of dry matter. These results teach clearly and emphatically that the fertilecondition of the soil induced by fallowing makes it possible toproduce dry matter with a smaller amount of water than can be doneon soils that are cropped continuously. The beneficial effects offallowing are therefore clearly twofold: to store the moisture oftwo seasons for the use of one crop; and to set free fertility toenable the plant to grow with the least amount of water. It is notyet fully understood what changes occur in fallowing to give thesoil the fertility which reduces the water needs of the plant. Theresearches of Atkinson in Montana, Stewart and Graves in Utah, andJensen in South Dakota make it seem probable that the formation ofnitrates plays an important part in the whole process. If a soil isof such a nature that neither careful, deep plowing at the righttime nor constant crust cultivation are sufficient to set free anabundance of plant-food, it may be necessary to apply manures orcommercial fertilizers to the soil. While the question of restoringsoil fertility has not yet come to be a leading one in dry-farming, yet in view of what has been said in this chapter it is notimpossible that the time will come when the farmers must giveprimary attention to soil fertility in addition to the storing andconservation of soil-moisture. The fertilizing of lands with properplant-foods, as shown in the last sections, tends to checktranspiration and makes possible the production of dry matter at thelowest water-cost. 

The recent practice in practically all dry-farm districts, at leastin the intermountain and far West, to use the header for harvestingbears directly upon the subject considered in this chapter. The highstubble which remains contains much valuable plant-food, oftengathered many feet below the surface by the plant roots. When thisstubble is plowed under there is a valuable addition of theplant-food to the upper soil. Further, as the stubble decays, acidsubstances are produced that act upon the soil grains to set freethe plant-food locked up in them. The plowing under of stubble istherefore of great value to the dry-farmer. The plowing under of anyother organic substance has the same effect. In both cases fertilityis concentrated near the surface, which dissolves in the soil-waterand enables the crop to mature with the Ieast quantity of water. 

The lesson then to be learned from this chapter is, that it is notaufficient for the dry-farmer to store an abundance of water in thesoil and to prevent that water from evaporating directly from thesoil; but the soil must be kept in such a state of high fertilitythat plants are enabled to utilize the stored moisture in the mosteconomical manner. Water storage, the prevention of evaporation, andthe maintenance of soil fertility go hand in hand in the developmentof a successful system of farming without irrigation. 

CHAPTER X

PLOWING AND FALLOWING

The soil treatment prescribed in the preceding chapters rests upon(1) deep and thorough plowing, done preferably in the fall; (2)thorough cultivation to form a mulch over the surface of the land, and (3) clean summer fallowing every other year under low rainfallor every third or fourth year under abundant rainfall. 

Students of dry-farming all agree that thorough cultivation of thetopsoil prevents the evaporation of soil-moisture, but some havequestioned the value of deep and fall plowing and the occasionalclean summer fallow. It is the purpose of this chapter to state thefindings of practical men with reference to the value of plowing andfallowing in producing large crop yields under dry-farm conditions. 

It will be shown in Chapter XVIII that the first attempts to producecrops without irrigation under a limited rainfall were madeindependently in many diverse places. California, Utah, and theColumbia Basin, as far as can now be learned, as well as the GreatPlains area, were all independent pioneers in the art ofdry-farming. It is a most significant fact that these diverselocalities, operating under different conditions as to soil andclimate, have developed practically the same system of dry-farming. In all these places the best dry-farmers practice deep plowingwherever the subsoil will permit it; fall plowing wherever theclimate will permit it; the sowing of fall grain wherever thewinters will permit it, and the clean summer fallow every otheryear, or every third or fourth year. H. W. Campbell, who has beenthe leading exponent of dry-farming in the Great Plains area, beganhis work without the clean summer fallow as a part of his system, but has long since adopted it for that section of the country. It isscarcely to be believed that these practices, developed laboriouslythrough a long succession of years in widely separated localities, do not rest upon correct scientific principles. In any case, theaccumulated experience of the dry-farmers in this country confirmsthe doctrines of soil tillage for dry-farms laid down in thepreceding chapters. 

At the Dry-Farming Congresses large numbers of practical farmersassemble for the purpose of exchanging experiences and views. Thereports of the Congress show a great difference of opinion on minormatters and a wonderful unanimity of opinion on the more fundamentalquestions. For instance, deep plowing was recommended by all whotouched upon the subject in their remarks; though one farmer, wholived in a locality the subsoil of which was very inert, recommendedthat the depth of plowing should be increased gradually until thefull depth is reached, to avoid a succession of poor crop yearswhile the lifeless soil was being vivified. The states of Utah, Montana, Wyoming, South Dakota, Colorado, Kansas, Nebraska, and theprovinces of Alberta and Saskatchewan of Canada all specificallydeclared through one to eight representatives from each state infavor of deep plowing as a fundamental practice in dry-farming. Fallplowing, wherever the climatic conditions make it possible, wassimilarly advocated by all the speakers. Farmers in certainlocalities had found the soil so dry in the fall that plowing wasdifficult, but Campbell insisted that even in such places it wouldbe profitable to use power enough to break up the land before thewinter season set in. Numerous speakers from the states of Utah, Wyoming, Montana, Nebraska, and a number of the Great Plains states, as well as from the Chinese Empire, declared themselves as favoringfall plowing. Scareely a dissenting voice was raised. 

In the discussion of the clean summer fallow as a vital principle ofdry-farming a slight difference of opinion was discovered. Farmersfrom some of the localities insisted that the clean summer fallowevery other year was indispensable; others that one in three yearswas sufficient; and others one in four years, and a few doubtful thewisdom of it altogether. However, all the speakers agreed that cleanand thorough cultivation should be practiced faithfully during thespring, and fall of the fallow year. The appreciation of the factthat weeds consume precious moisture and fertility seemed to begeneral among the dry-farmers from all sections of the country. Thefollowing states, provinces, and countries declared themselves asbeing definitely and emphatically in favor of clean summerfallowing:

California, Utah, Nevada, Washington, Montana, Idaho, Colorado, NewMexico, North Dakota, Nebraska, Alberta, Saskatchewan, Russia, Turkey, the Transvaal, Brazil, and Australia. Each of these manydistricts was represented by one to ten or more representatives. Theonly state to declare somewhat vigorously against it was from theGreat Plains area, and a warning voice was heard from the UnitedStates Department of Agriculture. The recorded practical experienceof the farmers over the whole of the dry-farm territory of theUnited States leads to the conviction that fallowing must heaccepted as a practice which resulted in successful dry-farming. Further, the experimental leaders in the dry-farm movement, whetherworking under private, state, or governmental direction, are, withvery few exceptions, strongly in favor of deep fall plowing andclean summer fallowing as parts of the dry-farm system. 

The chief reluctance to accept clean summer fallowing as a principleof dry-farming appears chicfly among students of the Great Plainsarea. Even there it is admitted by all that a wheat crop following afallow year is larger and better than one following wheat. Thereseem, however, to be two serious reasons for objecting to it. First, a fear that a clean summer fallow, practiced every second, third, orfourth year, will cause a large diminution of the organic matter inthe soil, resulting finally in complete crop failure; and second, abelief that a hoed crop, like corn or potatoes, exerts the samebeneficial effect. 

It is undoubtedly true that the thorough tillage involved indry-farming exposes to the action of the elements the organic matterof the soil and thereby favors rapid oxidation. For that reason thedifferent ways in which organic matter may be supplied regularly todry-farms are pointed out in Chapter XIV. It may also be observedthat the header harvesting system employed over a large part of thedry-farm territory leaves the large header stubble to be plowedunder, and it is probable that under such methods more organicmatter is added to the soil during the year of cropping than is lostduring the year of fallowing. It may, moreover, be observed thatthorough tillage of a crop like corn or potatoes tends to cause aloss of the organic matter of the soil to a degree nearly as largeas is the case when a fallow field is well cultivated. The thoroughstirring of the soil under an arid or semiarid climate, which is anessential feature of dry-farming, will always result in a decreasein organic matter. It matters little whether the soil is fallow orin crop during the process of cultivation, so far as the result isconcerned. 

A serious matter connected with fallowing in the Great Plains areais the blowing of the loose well-tilled soil of the fallow fields, which results from the heavy winds that blow so steadily over alarge part of the western slope of the Mississippi Valley. This islargely avoided when crops are grown on the land, even when it iswell tilled. 

The theory, recently proposed, that in the Great Plains area, wherethe rains come chicfly in summer, the growing of hoed crops may takethe place of the summer fallow, is said to be based on experimentaldata not yet published. Careful and conscientious experimenters, asChilcott and his co-laborers, indicate in their statements that inmany cases the yields of wheat, after a hoed crop, have been largerthan after a fallow year. The doctrine has, therefore, been ratherwidely disseminated that fallowing has no place in the dry-farmingof the Great Plains area and should be replaced by the growing ofhoed crops. Chilcott, who is the chief exponent of this doctrine, declares, however, that it is only with spring-grown crops and for asuccession of normal years that fallowing may be omitted, and thatfallowing must be resorted to as a safeguard or temporary expedientto guard against total loss of crop where extreme drouth isanticipated; that is, where the rainfall falls below the average. Hefurther explains that continuous grain cropping, even with carefulplowing and spring and fall tillage, is unsuccessful; but holds thatcertain rotations of crops, including grain and a hoed crop everyother year, are often more profitable than grain alternating withclean summer fallow. He further believes that the fallow year everythird or fourth year is sufficient for Great Plains conditions. Jardine explains that whenever fall grain is grown in the GreatPlains area, the fallow is remarkably helpful, and in fact becauseof the dry winters is practically indispensable. 

This latter view is confirmed by the experimental results obtainedby Atkinson and others at the Montana Experiment Stations, which areconducted under approximately Great Plains conditions. 

It should be mentioned also that in Saskatchewan, in the north endof the Great Plains area, and which is characteristic, except for alower annual temperature, of the whole area, and where dry-farminghas been practiced for a quarter of a century, the clean summerfallow has come to be an established practice. 

This recent discussion of the place of fallowing in the agricultureof the Great Plains area illustrates what has been said so often inthis volume about the adapting of principles to local conditions. Wherever the summer rainfall is sufficient to mature a crop, fallowing for the purpose of storing moisture in the soil isunnecessary; the only value of the fallow year under such conditionswould be to set free fertility. In the Great Plains area therainfall is somewhat higher than elsewhere in the dry-farm territoryand most of it comes in summer; and the summer precipitation isprobably enough in average years to mature crops, providing soilconditions are favorable. The main considerations, then, are to keepthe soils open for the reception of water and to maintain the soilsin a sufficiently fertile condition to produce, as explained inChapter IX, plants with a minimum amount of water. This isaccomplished very largely by the year of hoed crop, when the soil isas well stirred as under a clean fallow. 

The dry-farmer must never forget that the critical element indry-farming is water and that the annual rainfall will in the verynature of things vary from year to year, with the result that thedry year, or the year with a precipitation below the average, issure to come. In somewhat wet years the moisture stored in the soilis of comparatively little consequence, but in a year of drouth itwill be the main dependence of the farmer. Now, whether a crop behoed or not, it requires water for its growth, and land which iscontinuously cropped even with a variety of crops is likely to be solargely depleted of its moisture that, when the year of drouthcomes, failure will probably result. 

The precariousness of dry-farming must be done away with. The yearof drouth must be expected every year. Only as certainty of cropyield is assured will dry-farming rise to a respected place by theside of other branches of agriculture. To attain such certainty andrespect clean summer fallowing every second, third, or fourth year, according to the average rainfall, is probably indispensable; andfuture investigations, long enough continued, will doubtless confirmthis prediction. Undoubtedly, a rotation of crops, including hoedcrops, will find an important place in dry-farming, but probably notto the complete exclusion of the clean summer fallow. 

Jethro Tull, two hundred years ago, discovered that thorough tillageof the soil gave crops that in some cases could not be produced bythe addition of manure, and he came to the erroneous conclusion that"tillage is manure. " In recent days we have learned the value oftillage in conserving moisture and in enabling plants to reachmaturity with the least amount of water, and we may be tempted tobelieve that "tillage is moisture. " This, like Tull's statement, isa fallacy and must be avoided. Tillage can take the place ofmoisture only to a limited degree. Water is the essentialconsideration in dry-farming, else there would be no dry-farming. 

CHAPTER XI

SOWING AND HARVESTING

The careful application of the principles of soil treatmentdiscussed in the preceding chapters will leave the soil in goodcondition for sowing, either in the fall or spring. Nevertheless, though proper dry-farming insures a first-class seed-bed, theproblem of sowing is one of the most difficult in the successfulproduction of crops without irrigation. This is chiefly due to thedifficulty of choosing, under somewhat rainless conditions, a timefor sowing that will insure rapid and complete germination and theestablishmcnt of a root system capable of producing good plants. Insome respects fewer definite, reliable principles can be laid downconcerning sowing than any other principle of important applicationin the practice of dry-farming. The experience of the last fifteenyears has taught that the occasional failures to which even gooddry-farmers have been subjected have been caused almost wholly byuncontrollable unfavorable conditions prevailing at the time ofsowing. 

Conditions of germination

Three conditions determine germination: (1) heat, (2) oxygen, and(3) water. Unless these three conditions are all favorable, seedscannot germinate properly. The first requisite for successful seedgermination is a proper degree of heat. For every kind of seed thereis a temperature below which germination does not occur; another, above which it does not occur, and another, the best, at which, providing the other factors are favorable, germination will go onmost rapidly. The following table, constructed by Goodale, shows thelatest, highest, and best germination temperatures for wheat, barley, and corn. Other seeds germinate approximately within thesame ranges of temperature:--

Germination Temperatures (Degrees Farenheit)

 Lowest Highest BestWheat 41 108 84Barley 41 100 84Corn 49 115 91

Germination occurs within the considerable range between the highestand lowest temperatures of this table, though the rapidity ofgermination decreases as the temperature recedes from the best. Thisexplains the early spring and late fall germination when thetemperature is comparatively low. If the temperature falls below thelowest required for germination, dry seeds are not injured, and evena temperature far below the freezing point of water will not affectseeds unfavorably if they are not too moist. The warmth of the soil, essential to germination, cannot well be controlled by the farmer;and planting must, therefore, be done in seasons when, from pastexperience, it is probable that the temperature is and will remainin the neighborhood of the best degree for germination. More heat isrequired to raise the temperature of wet soils; therefore, seedswill generally germinate more slowly in wet than in dry soils, as isillustrated in the rapid germination often observed in well-tilleddry-farm soils. Consequently, it is safer at a low temperature tosow in dry soils than in wet ones. Dark soils absorb heat morerapidly than lighter colored ones, and under the same conditions oftemperature germination is therefore more likely to go on rapidly indark colored soils. Over the dry-farm territory the soils aregenerally light colored, which would tend to delay germination. Theincorporation of organic matter with the soil, which tends to darkenthe soil, has a slight though important bearing on germination aswell as on the general fertility of the soil, and should be made animportant dry-farm practice. Meanwhile, the temperature of the soildepends almost wholly upon the prevailing temperature conditions inthe district and is not to any material degree under the control ofthe farmer. 

A sufficient supply of oxygen in the soil is indispensable togermination. Oxygen, as is well known, forms about one fifth of theatmosphere and is the active principle in combustion and in tilechanges in the animal body occasioned by respiration. Oxygen shouldbe present in the soil air in approximately the proportion in whichit is found in the atmosphere. Germination is hindered by a largeror smaller proportion than is found in the atmosphere. The soil mustbe in such a condition that the air can easily enter or leave theupper soil layer; that is, the soil must be somewhat loose. In orderthat the seeds may have access to the necessary oxygen, then, sowingshould not be done in wet or packed soils, nor should the sowingimplements be such as to press the soil too closely around theseeds. Well-fallowed soil is in an ideal condition for admittingoxygen. 

If the temperature is right, germination begins by the forcibleabsorption of water by the seed from the surrounding soil. The forceof this absorption is very great, ranging from four hundred to fivehundred pounds per square inch, and continues until the seed iscompletely saturated. The great vigor with which water is thusabsorbed from the soil explains how seeds are able to secure thenecessary water from the thin water film surrounding the soilgrains. The following table, based upon numerous investigationsconducted in Germany and in Utah, shows the maximum percentages ofwater contained by seeds when the absorption is complete. Thesequantities are reached only when water is easily accessible:--

Percentage of Water contained by Seeds at Saturation

 German UtahRye 58 --Wheat 57 52Oats 58 43Barley 56 44Corn 44 57Beans 95 88Lucern 78 67

Germination itself does not go on freely until this maximumsaturation has been reached. Therefore, if the moisture in the soilis low, the absorption of water is made difficult and germination isretarded. This shows itself in a decreased percentage ofgermination. The effect upon germination of the percentage of waterin the soil is well shown by some of the Utah experiments, asfollows:--

Effect of Varying Amounts of Water on Percentage of Germination

Percent water in soil 7. 5 10 12. 5 15 17. 5 20 22. 5 25Wheat in sandy loam 0. 0 98 94 86 82 82 82 6Wheat in clay 30 48 84 94 84 82 86 58Beans in sandy loam 0 0 20 46 66 18 8 9Beans in clay 0 0 6 20 22 32 30 36Lucern in Sandy loam 0 18 68 54 54 8 8 9Lucern in clay 8 8 54 48 50 32 15 14

In a sandy soil a small percentage of water will cause bettergermination than in a clay soil. While different seeds vary in theirpower to abstract water from soils, yet it seems that for themajority of plants, the best percentage of soil-water forgermination purposes is that which is in the neighborhood of themaximum field capacity of soils for water, as explained in ChapterVII. Bogdanoff has estimated that the best amount of water in thesoil for germination purposes is about twice the maximum percentageof hygroscopic water. This would not be far from the field-watercapacity as described in the preceding chapter. 

During the absorption of water, seeds swell considerably, in manycases from two to three times their normal size. This has the verydesirable effect of crowding the seed walls against the soilparticles and thus, by establishing more points of contact, enablingthe seed to absorb moisture with greater facility. As seeds begin toabsorb water, heat is also produced. In many cases the temperaturesurrounding the seeds is increased one degree on the Centigradescale by the mere process of water absorption. This favors rapidgermination. Moreover, the fertility of the soil has a directinfluence upon germination. In fertile soils the germination is morerapid and more complete than in infertile soils. Especially activein favoring direct germination are the nitrates. When it is recalledthat the constant cultivation and well-kept summer fallow ofdry-farming develop large quantities of nitrates in the soil, itwill be understood that the methods of dry-farming as alreadyoutlined accelerate germination very greatly. 

It scareely need be said that the soil of the seed-bed should befine, mellow, and uniform in physical texture so that the seeds canbe planted evenly and in close contact with the soil particles. Allthe requisite conditions for germination are best met by theconditions prevailing in a well-kept summer fallowed soil. 

Time to sow

In the consideration of the time to sow, the first question to bedisposed of by the dry-farmer is that of fall as against springsowing. The small grains occur as fall and spring varieties, and itis vitally important to determine which season, under dry-farmconditions, is the best for sowing. 

The advantages of fall sowing are many. As stated, successfulgermination is favored by the presence of an abundance of fertility, especially of nitrates, in the soil. In summer-fallowed landnitrates are always found in abundance in the fall, ready tostimulate the seed into rapid germination and the young plants intovigorous growth. During the late fall and winter months the nitratesdisappear, at least in part, anti from the point of view offertility the spring is not so desirable as the fall forgermination. More important, grain sown in the fall under favorableconditions will establish a good root system which is ready for useand in action in the early spring as soon as the temperature isright and long before the farmer can go out on the ground with hisimplements. As a result, the crop has the use of the early springmoisture, which under the conditions of spring sowing is evaporatedinto the air. Where the natural precipitation is light and theamount of water stored in the soil is not large, the gain resultingfrom the use of the early spring moisture. Often decides thequestion in favor of fall sowing. 

The disadvantages of fall sowing are also many. The uncertainty ofthe fall rains must first be considered. In ordinary practice, seedsown in the fall does not germinate until a rain comes, unlessindeed sowing is done immediately after a rain. The fall rains areuncertain as to quantity. In many cases they are so light that theysuffice only to start germination and not to complete it and givethe plants the proper start. Such incomplete germination frequentlycauses the total loss of the crop. Even if the stand of the fallcrop is satisfactory, there is always the danger of winter-killingto be reckoned with. The real cause of winter-killing is not yetclearly understood, though it seems that repeated thawing andfreezing, drying winter winds, accompanied by dry cold or protractedperiods of intense cold, destroy the vitality of the seed and youngroot system. Continuous but moderate cold is not ordinarily veryinjurious. The liability to winter-killing is, therefore, very muchgreater wherever the winters are open than in places where the snowcovers the ground the larger part of the winter. It is also to bekept in mind that some varieties are very resistant towinter-killing, while others require well-covered winters. Fallsowing is preferable wherever the bulk of the precipitation comes inwinter and spring and where the winters are covered for some timewith snow and the summers are dry. Under such conditions it is veryimportant that the crop make use of the moisture stored in the soilin the early spring. Wherever the precipitation comes largely inlate spring and summer, the arguments in favor of fall sowing arenot so strong, and in such localities spring sowing is often moredesirable than fall sowing. In the Great Plains district, therefore, spring sowing is usually recommended, though fall-sown crops nearlyalways, even there, yield the larger crops. In the intermountainstates, with wet winters and dry summers, fall sowing has almostwholly replaced spring sowing. In fact, Farrell reports that uponthe Nephi (Utah) substation the average of six years shows abouttwenty bushels of wheat from fall-sown seed as against aboutthirteen bushels from spring-sown seed. Under the Californiaclimate, with wet winters and a winter temperature high enough forplant growth, fall sowing is also a general practice. Wherever theconditions are favorable, fall sowing should be practiced, for it isin harmony with the best principles of water conservation. Even indistricts where the precipitation comes chiefly in the summer, itmay be found that fall sowing, after all, is preferable. 

The right time to sow in the fall can be fixed only with greatdifficulty, for so much depends upon the climatic conditions. Infact the practice varies in accordance with differences in fallprecipitation and early fall frosts. Where numerous fall rainsmaintain the soil in a fairly moist condition and the temperature isnot too low, the problem is comparatively simple. In such districts, for latitudes represented by the dry-farm sections of the UnitedStates, a good time for fall planting is ordinarily from the firstof September to the middle of October. If sown much earlier in suchdistricts, the growth is likely to be too rank and subject todangerous injury by frosts, and as suggested by Farrell the verylarge development of the root system in the fall may cause, thefollowing summer, a dangerously large growth of foliage; that is, the crop may run to straw at the expense of the grain. If sown muchlater, the chances are that the crop will not possess sufficientvitality to withstand the cold of late fall and winter. Inlocalities where the late summer and the early fall are rainless, itis much more difficult to lay down a definite rule covering the timeof fall sowing. The dry-farmers in such places usually sow at anyconvenient time in the hope that an early rain will start theprocess of germination and growth. In other cases planting isdelayed until the arrival of the first fall rain. This is an certainand usually unsatisfactory practice, since it often happens that thesowing is delayed until too late in the fall for the best results. 

In districts of dry late summer and fall, the greatest danger independing upon the fall rains for germination lies in the fact thatthe precipitation is often so small that it initiates germinationwithout being sufficient to complete it. This means that when theseed is well started in germination, the moisture gives out. Whenanother slight rain comes a little later, germination is againstarted and possibly again stopped. In some seasons this may occurseveral times, to the permanent injury of the crop. Dry-farmers tryto provide against this danger by using an unusually large amount ofseed, assuming that a certain amount will fail to come up because ofthe repeated partial germinations. A number of investigators havedemonstrated that a seed may start to germinate, then be dried, andagain be started to germinate several times in succession withoutwholly destroying the vitality of the seed. 

In these experiments wheat and other seeds were allowed to germinateand dry seven times in succession. With each partial germination thepercentage of total germination decreased until at the seventhgermination only a few seeds of wheat, barley, and oats retainedtheir power. This, however, is practically the condition in dry-farmdistricts with rainless summers and falls, where fall seeding ispracticed. In such localities little dependence should be placed onthe fall rains and greater reliance placed on a method of soiltreatment that will insure good germination. For this purpose thesummer fallow has been demonstrated to be the most desirablepractice. If the soil has been treated according to the principleslaid down in earlier chapters, the fallowed land will, in the fall, contain a sufficient amount of moisture to produce completegermination though no rains may fall. Under such conditions the mainconsideration is to plant the seed so deep that it may draw freelyupon the stored soil-moisture. This method makes fall germinationsure in districts where the natural precipitation is not to bedepended upon. 

When sowing is done in the spring, there are few factors toconsider. Whenever the temperature is right and the soil has driedout sufficiently so that agricultural implements may be usedproperly, it is usually safe to begin sowing. The customs whichprevail generally with regard to the time of spring sowing may beadopted in dry-farm practices also. 

Depth of seeding

The depth to which seed should be planted in the soil is ofimportance in a system of dry-farming. The reserve materials inseeds are used to produce the first roots and the young plants. Nonew nutriment beyond that stored in the soil can be obtained by theplant until the leaves are above the ground able to gather Carletonfrom the atmosphere. The danger of deep planting lies, therefore, inexhausting the reserve materials of the seeds before the plant hasbeen able to push its leaves above the ground. Should this occur, the plant will probably die in the soil. On the other hand, if theseed is not planted deeply enough, it may happen that the rootscannot be sent down far enough to connect with the soil-waterreservoir below. Then, the root system will not be strong and deep, but will have to depend for its development upon the surface water, which is always a dangerous practice in dry-farming. The rule as tothe depth of seeding is simply: Plant as deeply as is safe. Thedepth to which seeds may be safely placed depends upon the nature ofthe soil, its fertility, its physical condition, and the water thatit contains. In sandy soils, planting may be deeper than in claysoils, for it requires less energy for a plant to push roots, stems, and leaves through the loose sandy soil than through the morecompact clay soil; in a dry soil planting may be deeper than in wetsoils; likewise, deep planting is safer in a loose soil than in onefirmly compacted; finally, where the moist soil is considerabledistance below the surface, deeper planting may be practiced thanwhen the moist soil is near the surface. Countless experiments havebeen conducted on the subject of depth of seeding. In a few cases, ordinary agricultural seeds planted eight inches deep have come upand produced satisfactory plants. However, the consensus of opinionis that from one to three inches are best in humid districts, butthat, everything considered, four inches is the best depth underdry-farm conditions. Under a low natural precipitation, where themethods of dry-farming are practiced, it is always safe to plantdeeply, for such a practice will develop and strengthen the rootsystem, which is one big step toward successful dry-farming. 

Quantity to sow

Numerous dry-farm failures may be charged wholly to ignoranceconcerning the quantity of seed to sow. In no other practice has thecustom of humid countries been followed more religiously bydry-farmers, and failure has nearly always resulted. The discussionsin this volume have brought out the fact that every plant ofwhatever character requires a large amount of water for its growth. From the first day of its growth to the day of its maturity, largeamounts of water are taken from the soil through the plant andevaporated into the air through the leaves. When the largequantities of seed employed in humid countries have been sown on drylands, the result has usually been an excellent stand early in theseason, with a crop splendid in appearance up to early summer. . Aluxuriant spring crop reduces, however, the water content of thesoil so greatly that when the heat of the summer arrives, there isnot sufficient water left in the soil to support the finaldevelopment and ripening. A thick stand in early spring is noassurance to the dry-farmer of a good harvest. On the contrary, itis usually the field with a thin stand in spring that stands up bestthrough the summer and yields most at the time of harvest. Thequantity of seed sown should vary with the soil conditions: the morefertile the soil is, the more seed may be used; the more water inthe soil, the more seed may be sown; as the fertility or the watercontent diminishes, the amount of seed should likewise bediminished. Under dry-farm conditions the fertility is good, but themoisture is low. As a general principle, therefore, light seedingshould be practiced on dry-farms, though it should be sufficient toyield a crop that will shade the ground well. If the sowing is doneearly, in fall or spring, less seed may be used than if the sowingis late, because the early sowing gives a better chance for rootdevelopment, which results, ordinarily, in more vigorous plants thatconsume more moisture than the smaller and weaker plants of latersowing. If the winters are mild and well covered with snow, lessseed may be used than in districts where severe or open winterscause a certain amount of winter-killing. On a good seed-bed offallowed soil less seed may be used than where the soil has not beencarefully tilled and is somewhat rough and lumpy and unfavorable forcomplete germination. The yield of any crop is not directlyproportional to the amount sown, unless all factors contributing togermination are alike. In the case of wheat and other grains, thinseeding also gives a plant a better chance for stooling, which isNature's method of adapting the plant to the prevailing moisture andfertility conditions. When plants are crowded, stooling cannot occurto any marked degree, and the crop is rendered helpless in attemptsto adapt itself to surrounding conditions. 

In general the rule may be laid down that a little more than onehalf as much seed should be used in dry-farm districts with anannual rainfall of about fifteen inches than is used in humiddistricts. That is, as against the customary five pecks of wheatused per acre in humid countries about three pecks or even two pecksshould be used on dry-farms. Merrill recommends the seeding of oatsat the rate of about three pecks per acre; of barley, about threepecks; of rye, two pecks; of alfalfa, six pounds; of corn, twokernels to the hill, and other crops in the same proportion. Noinvariable rule can be laid down for perfect germination. A smallquantity of seed is usually sufficient; but where germinationfrequently fails in part, more seed must be used. If the stand istoo thick at the beginning of the growing season, it must beharrowed out. Naturally, the quantity of seed to be used should bebased on the number of kernels as well as on the weight. Forinstance, since the larger the individual wheat kernels the fewer ina bushel, fewer plants would be produced from a bushel of large thanfrom a bushel of small seed wheat. The size of the seed indetermining the amount for sowing is often important and should bedetermined by some simple method, such as counting the seedsrequired to fill a small bottle. 

Method of sowing

There should really be no need of discussing the method of sowingwere it not that even at this day there are farmers in the dry-farmdistrict who sow by broadcasting and insist upon the superiority ofthis method. The broadcasting of seed has no place in any system ofscientific agriculture, least of all in dry-farming, where successdepends upon the degree with which all conditions are controlled. Inall good dry-farm practice seed should be placed in rows, preferablyby means of one of the numerous forms of drill seeders found uponthe market. The advantages of the drill are almost self-evident. Itpermits uniform distribution of the seed, which is indispensable forsuccess on soils that receive limited rainfall. The seed may beplaced at an even depth, which is very necessary, especially in fallsowing, where the seed depends for proper germination upon themoisture already stored in the soil. The deep seeding oftennecessary under dry-farm conditions makes the drill indispensable. Moreover, Hunt has explained that the drill furrows themselves havedefinite advantages. During the winter the furrows catch the snow, and because of the protection thus rendered, the seed is less likelyto be heaved out by repeated freezing and thawing. The drill furrowalso protects to a certain extent against the drying action of windsand in that way, though the furrows are small, they aid materiallyin enabling the young plant to pass through the winter successfully. The rains of fall and spring are accumulated in the furrows and madeeasily accessible to plants. Moreover, many of the drills haveattachments whereby the soil is pressed around the seed and thetopsoil afterwards stirred to prevent evaporation. This permits of amuch more rapid and complete germination. The drill, the advantagesof which were taught two hundred years ago by Jethro Tull, is one ofthe most valuable implements of modern agriculture. On dry-farms itis indispensable. The dry-farmer should make a careful study of thedrills on the market and choose such as comply with the principlesof the successful prosecution of dry-farming. Drill culture is theonly method of sowing that can be permitted if uniform success isdesired. 

The care of the crop

Excepting the special treatment for soil-moisture conservation, dry-farm crops should receive the treatment usually given cropsgrowing under humid conditions. The light rains that frequently fallin autumn sometimes form a crust on the top of the soil, whichhinders the proper germination and growth of the fall-sown crop. Itmay be necessary, therefore, for the farmer to go over the land inthe fall with a disk or more preferably with a corrugated roller. 

Ordinarily, however, after fall sowing there is no further need oftreatment until the following spring. The spring treatment is ofconsiderably more importance, for when the warmth of spring andearly summer begins to make itself felt, a crust forms over manykinds of dry-farm soils. This is especially true where the soil isof the distinctively arid kind and poor in organic matter. Such acrust should be broken early in order to give the young plants achance to develop freely. This may be accomplished, as above stated, by the use of a disk, corrugated roller, or ordinary smoothingharrow. 

When the young grain is well under way, it may be found to be toothick. If so, the crop may be thinned by going over the field with agood irontooth harrow with the teeth so set as to tear out a portionof the plants. This treatment may enable the remaining plants tomature with the limited amount of moisture in the soil. Paradoxically, if the crop seems to be too thin in the spring, harrowing may also be of service. In such a case the teeth should beslanted backwards and the harrowing done simply for the purpose ofstirring the soil without injury to the plant, to conserve themoisture stored in the soil and to accelerate the formation ofnitrates. --The conserved moisture and added fertility willstrengthen the growth and diminish the water requirements of theplants, and thus yield a larger crop. The iron-tooth harrow is avery useful implement on the dry-farm when the crops are young. After the plants are up so high that the harrow cannot be used onthem no special care need be given them, unless indeed they arecultivated crops like corn or potatoes which, of course, asexplained in previous chapters, should receive continualcultivation. 

Harvesting

The methods of harvesting crops on dry-farms are practically thosefor farms in humid districts. The one great exception may be the useof the header on the grain farms of the dry-farm sections. Theheader has now become well-nigh general in its use. Instead ofcutting and binding the grain, as in the old method, the heads aresimply cut off and piled in large stacks which later are threshed. The high straw which remains is plowed under in the fall and helpsto supply the soil with organic matter. The maintenance of dry-farmsfor over a generation without the addition of manures has been madepossible by the organic matter added to the soil in the decay of thehigh vigorous straw remaining after the header. In fact, the changesoccurring in the soil in connection with the decaying of the headerstubble appear to have actually increased the available fertility. Hundreds of Utah dry wheat farms during the last ten or twelve yearshave increased in fertility, or at least in productive power, dueundoubtedly to the introduction of the header system of harvesting. This system of harvesting also makes the practice of fallowing muchmore effective, for it helps maintain the organic matter which isdrawn upon by the fallow seasons. The header should be used whereverpracticable. The fear has been expressed that the high header strawplowed under will make the soil so loose as to render proper sowingdifficult and also, because of the easy circulation of air in theupper soil layers, cause a large loss of soil-moisture. This fearhas been found to be groundless, for wherever the header straw hasbeen plowed under; especially in connection with fallowing, the soilhas been benefited. 

Rapidity and economy in harvesting are vital factors in dry-farming, and new devices are constantly being offered to expedite the work. Of recent years the combined harvester and thresher has come intogeneral use. It is a large header combined with an ordinarythreshing machine. The grain is headed and threshed in one operationand the sacks dropped along the path of the machine. The straw isscattered over the field where it belongs. 

All in all, the question of sowing, care of crop, and harvesting maybe answered by the methods that have been so well developed incountries of abundant rainfall, except as new methods may berequired to offset the deficiency in the rainfall which is thedetermining condition of dry-farming. 

CHAPTER XII

CROPS FOR DRY-FARMING

The work of the dry-farmer is only half done when the soil has beenproperly prepared, by deep plowing, cultivation, fallowing, for theplanting of the crop. The choice of the crop, its proper seeding, and its correct care and harvesting are as important as rationalsoil treatment in the successful pursuit of dry-farming. It is truethat in general the kinds of crops ordinarily cultivated in humidregions are grown also on arid lands, but varieties especiallyadapted to the prevailing dry-farm conditions must be used if anycertainty of harvest is desired. Plants possess a marvelous power ofadaptation to environment, and this power becomes stronger assuccessive generations of plants are grown under the givenconditions. Thus, plants which have been grown for long periods oftime in countries of abundant rainfall and characteristic humidclimate and soil yield well under such conditions, but usuallysuffer and die or at best yield scantily if planted in hot rainlesscountries with deep soils. Yet, such plants, if grown year afteryear under arid conditions, become accustomed to warmth and drynessand in time will yield perhaps nearly as well or it may be better intheir new surroundings. The dry-farmer who looks for large harvestsmust use every care to secure varieties of crops that throughgenerations of breeding have become adapted to the conditionsprevailing on his farm. Home-grown seeds, if grown properly, aretherefore of the highest value. In fact, in the districts wheredry-farming has been practiced longest the best yielding varietiesare, with very few exceptions, those that have been grown for manysuccessive years on the same lands. The comparative newness of theattempts to produce profitable crops in the present dry-farmingterritory and the consequent absence of home-grown seed has renderedit wise to explore other regions of the world, with similar climaticconditions, but long inhabited, for suitable crop varieties. TheUnited States Department of Agriculture has accomplished much goodwork in this direction. The breeding of new varieties by scientificmethods is also important, though really valuable results cannot beexpected for many years to come. When results do come from breedingexperiments, they will probably be of the greatest value to thedry-farmer. Meanwhile, it must be acknowledged that at the present, our knowledge of dry-farm crops is extremely limited. Every yearwill probably bring new additions to the list and great improvementsof the crops and varieties now recommended. The progressivedry-farmer should therefore keep in close touch with state andgovernment workers concerning the best varieties to use. 

Moreover, while the various sections of the dry-farming territoryare alike in receiving a small amount of rainfall, they are widelydifferent in other conditions affecting plant growth, such as soils, winds, average temperature, and character and severity of thewinters. Until trials have been made in all these varyinglocalities, it is not safe to make unqualified recommendations ofany crop or crop variety. At the present we can only say that fordry-farm purposes we must have plants that will produce the maximumquantity of dry matter with the minimum quantity of water; and thattheir periods of growth must be the shortest possible. However, enough work has been done to establish some general rules for theguidance of the dry-farmer in the selection of crops. Undoubtedly, we have as yet had only a glimpse of the vast crop possibilities ofthe dry-farming territory in the United States, as well as in othercountries. 

Wheat

Wheat is the leading dry-farm crop. Every prospect indicates that itwill retain its preëminence. Not only is it the most generallyused cereal, but the world is rapidly learning to depend more andmore upon the dry-farming areas of the world for wheat production. In the arid and semiarid regions it is now a commonly accepteddoctrine that upon the expensive irrigated lands should be grownfruits, vegetables, sugar beets, and other intensive crops, whilewheat, corn, and other grains and even much of the forage should begrown as extensive crops upon the non-irrigated or dry-farm lands. It is to be hoped that the time is near at hand when it will be ararity to see grain grown upon irrigated soil, providing theclimatic conditions permit the raising of more extensive crops. 

In view of the present and future greatness of the wheat crop onsemiarid lands, it is very important to secure the varieties thatwill best meet the varying dry-farm conditions. Much has been doneto this end, but more needs to be done. Our knowledge of the bestwheats is still fragmentary. This is even more true of otherdry-farm crops. According to Jardine, the dry-farm wheats grown atpresent in the United States may be classificd as follows:--

I. Hard spring wheats:(a) Common(b) Durum

II. Winter wheats:(a) Hard wheats (Crimean)(b) Semihard wheats (Intermountain)(c) Soft wheats (Pactfic)

The common varieties of hard _spring wheats _are grown principallyin districts where winter wheats have not as yet been successful;that is, in the Dakotas, northwestern Nebraska, and other localitieswith long winters and periods of alternate thawing and severefreezing. The superior value of winter wheat has been so clearlydemonstrated that attempts are being made to develop in everylocality winter wheats that can endure the prevailing climaticconditions. Spring wheats are also grown in a scattering way and insmall quantities over the whole dry-farm territory. The two mostvaluable varieties of the common hard spring wheat are Blue Stem andRed Fife, both well-established varieties of excellent millingqualities, grown in immense quantities in the Northeastern corner ofthe dry-farm territory of the United States and commanding the bestprices on the markets of the world. It is notable that Red Fifeoriginated in Russia, the country which has given us so many gooddry-farm crops. 

The durum wheats or macaroni wheats, as they are often called, arealso spring wheats which promise to displace all other springvarieties because of their excellent yields under extreme dry-farmconditions. These wheats, though known for more than a generationthrough occasional shipments from Russia, Algeria, and Chile, wereintroduced to the farmers of the United States only in 1900, throughthe explorations and enthusiastic advocacy of Carleton of the UnitedStates Department of Agriculture. Since that time they have beengrown in nearly all the dryfarm states and especially in the GreatPlains area. Wherever tried they have yielded well, in some cases asmuch as the old established winter varieties. The extreme hardnessof these wheats made it difficult to induce the millers operatingmills fitted for grinding softer wheats to accept them forflourmaking purposes. This prejudice has, however, graduallyvanished, and to-day the durum wheats are in great demand, especially for blending with the softer wheats and for the making ofmacaroni. Recently the popularity of the durum wheats among thefarmers has been enhanced, owing to the discovery that they arestrongly rust resistant. 

The _winter wheats, _as has been repeatedly suggested in precedingchapters, are most desirable for dry-farm purposes, wherever theycan be grown, and especially in localities where a fairprecipitation occurs in the winter and spring. The hard winterwheats are represented mainly by the Crimean group, the chiefmembers of which are Turkey, Kharkow, and Crimean. These wheats alsooriginated in Russia and are said to have been brought to the UnitedStates a generation ago by Mennonite colonists. At present thesewheats are grown chiefly in the central and southern parts of theGreat Plains area and in Canada, though they are rapidly spreadingover the intermountain country. These are good milling wheats ofhigh gluten content and yielding abundantly under dry-farmconditions. It is quite clear that these wheats will soon displacethe older winter wheats formerly grown on dry-farms. Turkey wheatpromises to become the leading dry-farm wheat. The semisoft winterwheats are grown chiefly in the intermountain country. They arerepresented by a very large number of varieties, all tending towardsoftness and starchiness. This may in part be due to climatic, soil, and irrigation conditions, but is more likely a result of inherentqualities in the varieties used. They are rapidly being displaced byhard varieties. 

The group of soft winter wheats includes numerous varieties grownextensively in the famous wheat districts of California, Oregon, Washington, and northern Idaho. The main varieties are Red Russianand Palouse Blue Stem, in Washington and Idaho, Red Chaff and Foisein Oregon, and Defiance, Little Club, Sonora, and White Australianin California. These are all soft, white, and rather poor in gluten. It is believed that under given climatic, soil, and culturalconditions, all wheat varieties will approach one type, distinctiveof the conditions in question, and that the California wheat type isa result of prevailing unchangeable conditions. More researeh isneeded, however, before definite principles can be laid downconcerning the formation of distinctive wheat types in the variousdry-farm sections. Under any condition, a change of seed, keepingimprovement always in view, should be baneficial. 

Jardine has reminded the dry-farmers of the United States thatbefore the production of wheat on the dry-farms can reach its fullpossibilities under any acreage, sufficient quantities must be grownof a few varieties to affect the large markets. This is especiallyimportant in the intermountain country where no uniformity exists, but the warning should be heeded also by the Pacific coast and GreatPlains wheat areas. As soon as the best varieties are found theyshould displace the miscellaneous collection of wheat varieties nowgrown. The individual farmer can be a law unto himself no more inwheat growing than in fruit growing, if he desires to reap thelargest reward of his efforts. Only by uniformity of kind andquality and large production will any one locality impress itselfupon the markets and create a demand. The changes now in progress bythe dry-farmers of the United States indicate that this lesson hasbeen taken to heart. The principle is equally important for allcountries where dry-farming is practiced. 

Other small grains

_Oats _is undoubtedly a coming dry-farm crop. Several varieties havebeen found which yield well on lands that receive an average annualrainfall of less than fifteen inches. Others will no doubt bediscovered or developed as special attention is given to dry-farmoats. Oats occurs as spring and winter varieties, but only onewinter variety has as yet found place in the list of dry-farm crops. The leading; spring varieties of oats are the Sixty-Day, Kherson, Burt, and Swedish Select. The one winter variety, which is grownchiefly in Utah, is the Boswell, a black variety originally broughtfrom England about 1901. 

_Barley, _like the other common grains, occurs in varieties thatgrow well on dry-farms. In comparison with wheat very little searehhas been made for dry-farm barleys, and, naturally, the list oftested varieties is very small. Like wheat and oats, barley occursin spring and winter varieties, but as in the case of oats only onewinter variety has as yet found its way into the approved list ofdry-farm crops. The best dry-farm spring barleys are those belongingto the beardless and hull-less types, though the more commonvarieties also yield well, especially the six-rowed beardlessbarley. The winter variety is the Tennessee Winter, which is alreadywell distributed over the Great Plains district. 

_Rye _is one of the surest dry-farm crops. It yields good crops ofstraw and grain, both of which are valuable stock foods. In fact, the great power of rye to survive and grow luxuriantly under themost trying dry-farm conditions is the chief objection to it. Oncestarted, it is hard to eradicate. Properly cultivated and usedeither as a stock feed or as green manure, it is very valuable. Ryeoccurs as both spring and winter varieties. The winter varieties areusually most satisfactory. 

Carleton has recommended _emmer _as a crop peculiarly adapted tosemiarid conditions. Emmer is a species of wheat to the berries ofwhich the chaff adheres very closely. It is highly prized as a stockfeed. In Russia and Germany it is grown in very large quantities. Itis especially adapted to arid and semiarid conditions, but willprobably thrive best where the winters are dry and summers wet. Itexists as spring and winter varieties. Is with the other smallgrains, the success of emmer will depend largely upon thesatisfactory development of winter varieties. 

Corn

Of all crops yet tried on dry-farms, corn is perhaps the mostuniformly successful under extreme dry conditions. If the soiltreatment and planting have been right, the failures that have beenreported may invariably be traced to the use of seed which had notbeen acclimated. The American Indians grow corn which is excellentfor dry-farm purposes; many of the western farmers have likewiseproduced strains that use the minimum of moisture, and, moreover, corn brought from humid sections adapts itself to arid conditions ina very few years. Escobar reports a native corn grown in Mexico withlow stalks and small ears that well endures desert conditions. Inextremely dry years corn does not always produce a profitable cropof seed, but the crop as a whole, for forage purposes, seldom failsto pay expenses and leave a margin for profit. In wetter years thereis a corresponding increase of the corn crop. The dryfarmingterritory does not yet realize the value of corn as a dry-farm crop. The known facts concerning corn make it safe to predict, however, that its dry farm acreage will increase rapidly, and that in time itwill crowd the wheat crop for preëminence. 

Sorghums

Among dry-farm crops not popularly known are the sorghums, whichpromise to become excellent yielders under arid conditions. Thesorghums are supposed to have come grown the tropical sections ofthe globe, but they are now scattered over the earth in all climes. The sorghums have been known in the United States for over half acentury, but it was only when dry-farming began to develop sotremendously that the drouth-resisting power of the sorghums wasrecalled. According to Ball, the sorghums fall into the followingclasses:--

THE SORGHUMS

1. Broom corns2. Sorgas or sweet sorghums3. Kafirs4. Durras

The broom corns are grown only for their brush, and are notconsidered in dry-farming; the sorgas for forage and sirups, and areespecially adapted for irrigation or humid conditions, though theyare said to endure dry-farm conditions better than corn. The Kafirsare dry-farm crops and are grown for grain and forage. This groupincludes Red Kafir, White Kafir, Black-hulled White Kafir, and WhiteMilo, all of which are valuable for dry-farming. The Durras aregrown almost exclusively for seed and include Jerusalem corn, BrownDurra, and Milo. The work of Ball has made Milo one of the mostimportant dry-farm crops. As improved, the crop is from four to fourand a half feet high, with mostly erect heads, carrying a largequantity of seeds. Milo is already a staple crop in parts of Texas, Oklahoma, Kansas, and New Mexico. It has further been shown to beadapted to conditions in the Dakotas, Nebraska, Colorado, Arizona, Utah, and Idaho. It will probably be found, in some varietal form, valuable over the whole dry-farm territory where the altitude is nottoo high and the average temperature not too low. 

It has yielded an average of forty bushels of seed to the acre. 

Lucern or alfalfa

Next to human intelligence and industry, alfalfa has probably beenthe chief factor in the development of the irrigated West. It hasmade possible a rational system of agriculture, with the live-stockindustry and the maintenance of soil fertility as the centralconsiderations. Alfalfa is now being recognized as a desirable cropin humid as well as in irrigated sections, and it is probable thatalfalfa will soon become the chief hay crop of the United States. Originally, lucern came from the hot dry countries of Asia, where itsupplied feed to the animals of the first historical peoples. Moreover, its long; tap roots, penetrating sometimes forty or fiftyfeet into the ground, suggest that lucern may make ready use ofdeeply stored soil-moisture. On these considerations, alone, lucernshould prove itself a crop well suited for dry-farming. In fact, ithas been demonstrated that where conditions are favorable, lucernmay be made to yield profitable crops under a rainfall betweentwelve and fifteen inches. Alfalfa prefers calcareous loamy soils;sandy and heavy clay soils are not so well adapted for successfulalfalfa production. Under dry-farm conditions the utmost care mustbe used to prevent too thick seeding. The vast majority of alfalfafailures on dry-farms have resulted from an insufficient supply ofmoisture for the thickly planted crop. The alfalfa field does notattain its maturity until after the second year, and a crop whichlooks just right the second year will probably be much too thick thethird and fourth years. From four to six pounds of seed per acre areusually ample. Another main cause of failure is the common idea thatthe lucern field needs little or no cultivation, when, in fact, thealfalfa field should receive as careful soil treatment as the wheatfield. Heavy, thorough disking in spring or fall, or both, isadvisable, for it leaves the topsoil in a condition to preventevaporation and admit air. In Asiatic and North African countries, lucern is frequently cultivated between rows throughout the hotseason. This has been tried by Brand in this country and with verygood results. Since the crop should always be sown with a drill, itis comparatively easy to regulate the distance between the rows sothat cultivating implements may be used. If thin seeding andthorough soil stirring are practiced, lucern usually grows well, andwith such treatment should become one of the great dry-farm crops. The yield of hay is not large, but sufficient to leave a comfortablemargin of profit. Many farmers find it more profitable to growdry-farm lucern for seed. In good years from fifty to one hundredand fifty dollars may be taken from an acre of lucern seed. However, at the present, the principles of lucern seed production are notwell established, and the seed crop is uncertain. 

Alfalfa is a leguminous crop and gathers nitrogen from the air. Itis therefore a good fertilizer. The question of soil fertility willbecome more important with the passing of the years, and the valueof lucern as a land improver will then be more evident than it isto-day. 

Other leguminous crops

The group of leguminous or pod-bearing crops is of great importance;first, because it is rich in nitrogenous substances which arevaluable animal foods, and, secondly, because it has the power ofgathering nitrogen from the air, which can be used for maintainingthe fertility of the soil. Dry-farming will not be a wholly safepractice of agriculture until suitable leguminous crops are foundand made part of the crop system. It is notable that over the wholeof the dry-farm territory of this and other countries wildleguminous plants flourish. That is, nitrogen-gathering plants areat work on the deserts. The farmer upsets this natural order ofthings by cropping the land with wheat and wheat only, so long asthe land will produce profitably. The leguminous plants native todry-farm areas have not as yet been subjected to extensive economicstudy, and in truth very little is known concerning leguminousplants adapted to dry-farming. 

In California, Colorado, and other dry-farm states the field pea hasbeen grown with great profit. Indeed it has been found much moreprofitable than wheat production. The field bean, likewise, has beengrown successfully under dry-farm conditions, under a great varietyof climates. In Mexico and other southern climates, the nativepopulation produce large quantities of beans upon their dry lands. 

Shaw suggests that sanfoin, long famous for its service to Europeanagriculture, may be found to be a profitable dry-farm crop, and thatsand vetch promises to become an excellent dry-farm crop. It is verylikely, however, that many of the leguminous crops which have beendeveloped under conditions of abundant rainfall will be valueless ondry-farm lands. Every year will furnish new and more completeinformation on this subject. Leguminous plants will surely becomeimportant members of the association of dry-farm crops. 

Trees and shrubs

So far, trees cannot be said to be dry-farm crops, though facts areon record that indicate that by the application of correct dry-farmprinciples trees may be made to grow and yield profitably ondry-farm lands. Of course, it is a well-known fact that native treesof various kinds are occasionally found growing on the deserts, where the rainfall is very light and the soil has been given nocare. Examples of such vegetation are the native cedars foundthroughout the Great Basin region and the mesquite tree in Arizonaand the Southwest. Few farmers in the arid region have as yetundertaken tree culture without the aid of irrigation. 

At least one peach orchard is known in Utah which grows under arainfall of about fifteen inches without irrigation and producesregularly a small crop of most delicious fruit. Parsons describeshis Colorado dry-farm orchard in which, under a rainfall of almostfourteen inches, he grows, with great profit, cherries, plums, andapples. A number of prospering young orchards are growing withoutirrigation in the Great Plains area. Mason discovered a few yearsago two olive orchards in Arizona and the Colorado desert which, planted about fourteen years previously, were thriving under anannual rainfall of eight and a half and four and a half inches, respectively. These olive orchards had been set out under canalswhich later failed. Such attested facts lead to the thought thattrees may yet take their place as dry-farm crops. This hope isstrengthened when it is recalled that the great nations ofantiquity, living in countries of low rainfall, grew profitably andwithout irrigation many valuable trees, some of which are stillcultivated in those countries. The olive industry, for example, iseven now being successfully developed by modern methods in Asiaticand African sections, where the average annual rainfall is under teninches. Since 1881, under French management, the dry-farm olivetrees around Tunis have increased from 45, 000 to 400, 000individuals. Mason and also Aaronsohn suggest as trees that do wellin the arid parts of the old world the so-called "Chinese date" orJuJube tree, the sycamore fig, and the Carob tree, which yields the"St. John's Bread" so dear to childhood. 

Of this last tree, Aaronsolm says that twenty trees to the acre, under a rainfall of twelve inches, will produce 8000 pounds of fruitcontaining 40 per cent of sugar and 7 to 8 per cent of protein. Thissurpasses the best harvest of alfalfa. Kearnley, who has made aspecial study of dry-land olive culture in northern Africa, statesthat in his belief a large variety of fruit trees may be found whichwill do well under arid and semiarid conditions, and may even yieldmore profit than the grains. 

It is also said that many shade and ornamental and other usefulplants can be grown on dry-farms; as, for instance, locust, elm, black walnut, silverpoplar, catalpa, live oak, black oak, yellowpine, red spruce, Douglas fir, and cedar. 

The secret of success in tree growing on dry-farms seems to lie, first, in planting a few trees per acre, --the distance apart shouldbe twice the ordinary distance, --and, secondly, in applyingvigorously and unceasingly the established principles of soilcultivation. In a soil stored deeply with moisture and properlycultivated, most plants will grow. If the soil has not beencarefully fallowed before planting, it may be necessary to water theyoung trees slightly during the first two seasons. 

Small fruits have been tried on many farms with great success. Plums, currants, and gooseberries have all been successful. Grapesgrow and yield well in many dry-farm districts, especially along thewarm foothills of the Great Basin. Tree growing on dry-farm lands isnot yet well established and, therefore, should be undertaken withgreat care. Varieties accustomed to the climatic environment shouldbe chosen, and the principles outlined in the preceding pages shouldbe carefully used. 

Potatoes

In recent years, potatoes have become one of the best dry-farmcrops. Almost wherever tried on lands under a rainfall of twelveinches or more potatoes have given comparatively large yields. To-day, the growing of dry-farm potatoes is becoming an importantindustry. The principles of light seeding and thorough cultivationare indispensable for success. Potatoes are well adapted for use inrotations, where summer fallowing is not thought desirable. Macdonald enumerates the following as the best varieties at presentused on dry-farms: Ohio, Mammoth, Pearl, Rural New Yorker, andBurbank. 

Miscellaneous

A further list of dry-farm crops would include representatives ofnearly all economic plants, most of them tried in small quantity invarious localities. Sugar beets, vegetables, bulbous plants, etc. , have all been grown without irrigation under dry-farm conditions. Some of these will no doubt be found to be profitable and will thenbe brought into the commercial scheme of dry-farming. 

Meanwhile, the crop problems of dry-farming demand that much carefulwork be done in the immediate future by the agencies having suchwork in charge. The best varieties of crops already in profitableuse need to be determined. More new plants from all parts of theworld need to be brought to this new dry-farm territory and triedout. Many of the native plants need examination with a view to theireconomic use. For instance, the sego lily bulbs, upon which the Utahpioneers subsisted for several seasons of famine, may possibly bemade a cultivated crop. Finally, it remains to be said that it isdoubtful wisdom to attempt to grow the more intensive crops ondry-farms. Irrigation and dry-farming will always go together. Theyare supplementary systems of agriculture in arid and semiaridregions. On the irrigated lands should be grown the crops thatrequire much labor per acre and that in return yield largely peracre. New crops and varieties should besought for the irrigatedfarms. On the dry-farms should be grown the crops that can behandled in a large way and at a small cost per acre, and that yieldonly moderate acre returns. By such cooperation between irrigationand dry-farming will the regions of the world with a scanty rainfallbecome the healthiest, wealthiest, happiest, and most populous onearth. 

CHAPTER XIII

THE COMPOSITION OF DRY-FARM CROPS

The acre-yields of crops on dry-farms, even under the most favorablemethods of culture, are likely to be much smaller than in humidsections with fertile soils. The necessity for frequent fallowing orresting periods over a large portion of the dry-farm territoryfurther decreases the average annual yield. It does not follow fromthis condition that dry-farming is less profitable than humid-orirrigation-farming, for it has been fully demonstrated that theprofit on the investment is as high under proper dry-farming asunder any other similar generally adopted system of farming in anypart of the world. Yet the practice of dry-farming would appear tobe, and indeed would be, much more desirable could the crop yield beincreased. The discovery of any condition which will offset thesmall annual yields is, therefore, of the highest importance to theadvancement of dry-farming. The recognition of the superior qualityof practically all crops grown without irrigation under a limitedrainfall has done much to stimulate faith in the greatprofitableness of dry-farming. As the varying nature of thematerials used by man for food, clothing, and shelter has becomemore clearly understood, more attention has been given to thevaluation of commercial products on the basis of quality as well asof quantity. Sugar beets, for instance, are bought by the sugarfactories under a guarantee of a minimum sugar content; and manyfactories of Europe vary the price paid according to the sugarcontained by the beets. The millers, especially in certain parts ofthe country where wheat has deteriorated, distinguish carefullybetween the flour-producing qualities of wheats from varioussections and fix the price accordingly. Even in the household, information concerning the real nutritive value of various foods isbeing sought eagerly, and foods let down to possess the highestvalue in the maintenance of life are displacing, even at a highercost, the inferior products. The quality valuation is, in fact, being extended as rapidly as the growth of knowledge will permit tothe chief food materials of commerce. As this practice becomes fixedthe dry-farmer will be able to command the best market prices forhis products, for it is undoubtedly true that from the point of viewof quality, dry-farm food products may be placed safely incompetition with any farm products on the markets of the world. 

Proportion of plant parts

It need hardly be said, after the discussions in the precedingchapters, that the nature of plant growth is deeply modified by thearid conditions prevailing in dry-farming. This shows itself firstin the proportion of the various plant parts, such as roots, stems, leaves, and seeds. The root systems of dry-farm crops are generallygreatly developed, and it is a common observation that in adverseseasons the plants that possess the largest and most vigorous rootsendure best the drouth and burning heat. The first function of theleaves is to gather materials for the building and strengthening ofthe roots, and only after this has been done do the stems lengthenand the leaves thicken. Usually, the short season is largely gonebefore the stem and leaf growth begins, and, consequently, asomewhat dwarfed appearance is characteristic of dry-farm crops. Thesize of sugar beets, potato tubers, and such underground partsdepends upon the available water and food supply when the plant hasestablished a satisfactory root and leaf system. If the water andfood are scarce, a thin beet results; if abundant, a well-filledbeet may result. 

Dry-farming is characterized by a somewhat short season. Even ifgood growing weather prevails, the decrease of water in the soil hasthe effect of hastening maturity. The formation of flowers and seedbegins, therefore, earlier and is completed more quickly under aridthan under humid conditions. Moreover, and resulting probably fromthe greater abundance of materials stored in the root system, theproportion of heads to leaves and stems is highest in dry-farmcrops. In fact, it is a general law that the proportion of heads tostraw in grain crops increases as the water supply decreases. Thisis shown very well even under humid or irrigation conditions whendifferent seasons or different applications of irrigation water arecompared. For instance, Hall quotes from the Rothamsted experimentsto the effect that in 1879, which was a wet year (41 inches), thewheat crop yielded 38 pounds of grain for every 100 pounds of straw;whereas, in 1893, which was a dry year (23 inches), the wheat cropyielded 95 pounds of grain to every 100 pounds of straw. The Utahstation likewise has established the same law under arid conditions. In one series of experiments it was shown as an average of threeyears' trial that a field which had received 22. 5 inches ofirrigation water produced a wheat crop that gave 67 pounds of grainto every 100 pounds of straw; while another field which receivedonly 7. 5 inches of irrigation water produced a crop that gave 100pounds of grain for every 100 pounds of straw. Since wheat is grownessentially for the grain, such a variation is of tremendousimportance. The amount of available water affects every part of theplant. Thus, as an illustration, Carleton states that the per centof meat in oats grown in Wisconsin under humid conditions was 67. 24, while in North Dakota, Kansas, and Montana, under arid and semiaridconditions, it was 71. 51. Similar variations of plant parts may beobserved as a direct result of varying the amount of availablewater. In general then, it may be said that the roots of dry-farmcrops are well developed; the parts above ground somewhat dwarfed;the proportion of seed to straw high, and the proportion of meat ornutritive materials in the plant parts likewise high. 

The water in dry-farm crops

One of the constant constituents of all plants and plant parts iswater. Hay, flour, and starch contain comparatively large quantitiesof water, which can be removed only by heat. The water in greenplants is often very large. In young lucern, for instance, itreaches 85 per cent, and in young peas nearly 90 per cent, or morethan is found in good cow's milk. The water so held by plants has nonutritive value above ordinary water. It is, therefore, profitablefor the consumer to buy dry foods. In this particular, again, dry-farm crops have a distinct advantage: During growth there is notperhaps a great difference in the water content of plants, due toclimatic differences, but after harvest the drying-out process goeson much more completely in dry-farm than in humid districts. Hay, cured in humid regions, often contains from 12 to 20 per cent ofwater; in arid climates it contains as little as 5 per cent andseldom more than 12 per cent. The drier hay is naturally morevaluable pound for pound than the moister hay, and a difference inprice, based upon the difference in water content, is already beingfelt in certain sections of the West. 

The moisture content of dry-farm wheat, the chief dry-farm crop, iseven more important. According to Wiley the average water content ofwheat for the United States is 10. 62 per cent, ranging from 15 to 7per cent. Stewart and Greaves examined a large number of wheatsgrown on the dry-farms of Utah and found that the average per centof water in the common bread varieties was 8. 46 and in the durumvarieties 8. 89. This means that the Utah dry-farm wheats transportedto ordinary humid conditions would take up enough water from the airto increase their weight one fortieth, or 2. 2 per cent, before theyreached the average water content of American wheats. In otherwords, 1, 000, 000 bushels of Utah dry-farm wheat contain as muchnutritive matter as 1, 025, 000 bushels of wheat grown and kept underhumid conditions. This difference should be and now is recognized inthe prices paid. In fact, shrewd dealers, acquainted with thedryness of dry-farm wheat, have for some years bought wheat from thedry-farms at a slightly increased price, and trusted to the increasein weight due to water absorption in more humid climates for theirprofits. The time should be near at hand when grains and similarproducts should be purchased upon the basis of a moisture test. 

While it is undoubtedly true that dry-farm crops are naturally drierthan those of humid countries, yet it must also be kept in mind thatthe driest dry-farm crops are always obtained where the summers arehot and rainless. In sections where the precipitation comes chieflyin the spring and summer the difference would not be so great. Therefore, the crops raised on the Great Plains would not be so dryas those raised in California or in the Great Basin. Yet, whereverthe annual rainfall is so small as to establish dry-farm conditions, whether it comes in the winter or summer, the cured crops are drierthan those produced under conditions of a much higher rainfall, anddry farmers should insist that, so far as possible in the future, sales be based on dry matter. 

The nutritive substances in crops

The dry matter of all plants and plant parts consists of three verydistinct classes of substances: First, ash or the mineralconstituents. Ash is used by the body in building bones and insupplying the blood with compounds essential to the various lifeprocesses. Second, protein or the substances containing the elementnitrogen. Protein is used by the body in making blood, muscle, tendons, hair, and nails, and under certain conditions it is burnedwithin the body for the production of heat. Protein is perhaps themost important food constituent. Third, non-nitrogenous substances, including fats, woody fiber, and nitrogen-free extract, a name givento the group of sugars, starehes, and related substances. Thesesubstances are used by the body in the production of fat, and arealso burned for the production of heat. Of these valuable foodconstituents protein is probably the most important, first, becauseit forms the most important tissues of the body and, secondly, because it is less abundant than the fats, starches, and sugars. Indeed, plants rich in protein nearly always command the highestprices. 

The composition of any class of plants varies considerably indifferent localities and in different seasons. This may be due tothe nature of the soil, or to the fertilizer applied, thoughvariations in plant composition resulting from soil conditions arecomparatively small. The greater variations are almost wholly theresult of varying climate and water supply. As far as it is nowknown the strongest single factor in changing the composition ofplants is the amount of water available to the growing plant. 

Variations due to varying water supply

The Utah station has conducted numerous experiments upon the effectof water upon plant composition. The method in every case has beento apply different amounts of water throughout the growing season oncontiguous plats of uniform land. [Lengthy table deleated from thisedition. ] Even a casual study of . . . [the results show] that thequantity of water used influenced the composition of the plantparts. The ash and the fiber do not appear to be greatly influenced, but the other constituents vary with considerable regularity withthe variations in the amount of irrigation water. The protein showsthe greatest variation. As the irrigation water is increased, thepercentage of protein decreases. In the case of wheat the variationwas over 9 per cent. The percentage of fat and nitrogen-freeextract, on the other hand, becomes larger as the water increases. That is, crops grown with little water, as in dry-farming, are richin the important flesh-and blood-forming substance protein, andcomparatively poor in fat, sugar, stareh, and other of the moreabundant heat and fat-producing substances. This difference is oftremendous importance in placing dry-farming products on the foodmarkets of the world. Not only seeds, tubers, and roots show thisvariation, but the stems and leaves of plants grown with littlewater are found to contain a higher percentage of protein than thosegrown in more humid climates. 

The direct effect of water upon the composition of plants has beenobserved by many students. For instance, Mayer, working in Holland, found that, in a soil containing throughout the season 10 per centof water, oats was produced containing 10. 6 per cent of protein; insoil containing 30 per cent of water, the protein percentage wasonly 5. 6 per cent, and in soil containing 70 per cent of water, itwas only 5. 2 per cent. Carleton, in a study of analyses of the samevarieties of wheat grown in humid and semi-arid districts of theUnited States, found that the percentage of protein in wheat fromthe semiarid area was 14. 4 per cent as against 11. 94 per cent in thewheat from the humid area. The average protein content of the wheatof the United States is a little more than 12 per cent; Stewart andGreaves found an average of 16. 76 per cent of protein in Utahdry-farm wheats of the common bread varieties and 17. 14 per cent inthe durum varieties. The experiments conducted at Rothamsted, England, as given by Hall, confirm these results. For example, during 1893, a very dry year, barley kernels contained 12. 99 percent of protein, while in 1894, a wet, though free-growing year, thebarley contained only 9. 81 per cent of protein. Quotations might bemultiplied confirming the principle that crops grown with littlewater contain much protein and little heat-and fat-producingsubstances. 

Climate and composition

The general climate, especially as regards the length of the growingseason and naturally including the water supply, has a strong effectupon the composition of plants. Carleton observed that the samevarieties of wheat grown at Nephi, Utah, contained 16. 61 per centprotein; at Amarillo, Texas, 15. 25 per cent; and at McPherson, Kansas, a humid station, 13. 04 per cent. This variation isundoubtedly due in part to the varying annual precipitation but, also, and in large part, to the varying general climatic conditionsat the three stations. 

An extremely interesting and important experiment, showing theeffect of locality upon the composition of wheat kernels, isreported by LeClerc and Leavitt. Wheat grown in 1905 in Kansas wasplanted in 1906 in Kansas, California, and Texas In 1907 samples ofthe seeds grown at these three points were planted side by side ateach of the three states All the crops from the three localitieswere analyzed separately each year. 

The results are striking and convincing. The original seed grown inKansas in 1905 contained 16. 22 per cent of protein. The 1906 cropgrown from this seed in Kansas contained 19. 13 per cent protein; inCalifornia, 10. 38 percent; and in Texas, 12. 18 percent. In 1907 thecrop harvested in Kansas from the 1906 seed from these widelyseparated places and of very different composition containeduniformly somewhat more than 22 per cent of protein; harvested inCalifornia, somewhat more than 11 per cent; and harvested in Texas, about 18 per cent. In short, the composition of wheat kernels isindependent of the composition of the seed or the nature of thesoil, but depends primarily upon the prevailing climatic conditions, including the water supply. The weight of the wheat per bushel, thatis, the average size and weight of the wheat kernel, and also thehardness or flinty character of the kernels, were strongly affectedby the varying climatic conditions. It is generally true thatdry-farm grain weighs more per bushel than grain grown under humidconditions; hardness usually accompanies a high protein content andis therefore characteristic of dry-farm wheat. These notable lessonsteach the futility of bringing in new seed from far distant placesin the hope that better and larger crops may be secured. Theconditions under which growth occurs determine chiefly the nature ofthe crop. It is a common experience in the West that farmers who donot understand this principle send to the Middle West for seed corn, with the result that great crops of stalks and leaves with no earsare obtained. The only safe rule for the dry-farmer to follow is touse seed which has been grown for many years under dry-farmconditions. 

A reason for variation in composition

It is possible to suggest a reason for the high protein content ofdry-farm crops. It is well known that all plants secure most oftheir nitrogen early in the growing period. From the nitrogen, protein is formed, and all young plants are, therefore, very rich inprotein. As the plant becomes older, little more protein is added, but more and more carbon is taken from the air to form the fats, starches, sugars, and other non-nitrogenous substances. Consequently, the proportion or percentage of protein becomessmaller as the plant becomes older. The impelling purpose of theplant is to produce seed. Whenever the water supply begins to giveout, or the season shortens in any other way, the plant immediatelybegins to ripen. Now, the essential effect of dry-farm conditions isto shorten the season; the comparatively young plants, yet rich inprotein, begin to produce seed; and at harvest, seed, and leaves, and stalks are rich in the flesh-and blood-forming element ofplants. In more humid countries plants delay the time of seedproduction and thus enable the plants to store up more carbon andthus reduce the percent of protein. The short growing season, induced by the shortness of water, is undoubtedly the main reasonfor the higher protein content and consequently higher nutritivevalue of all dry-farm crops. 

Nutritive value of dry-farm hay, straw, and flour

All the parts of dry-farm crops are highly nutritious. This needs tobe more clearly understood by the dry-farmers. Dry-farm hay, forinstance, because of its high protein content, may be fed with cropsnot so rich in this element, thereby making a larger profit for thefarmer. Dry-farm straw often has the feeding value of good hay, ashas been demonstrated by analyses and by feeding tests conducted intimes of hay scarcity. Especially is the header straw of highfeeding value, for it represents the upper and more nutritious endsof the stalks. Dry-farm straw, therefore, should be carefully keptand fed to animals instead of being scattered over the ground oreven burned as is too often the case. Only few feeding experimentshaving in view the relative feeding value of dry-farm crops have asyet been made, but the few on record agree in showing the superiorvalue of dry-farm crops, whether fed singly or in combination. 

The differences in the chemical composition of plants and plantproducts induced by differences in the water-supply and climaticenvironment appear in the manufactured products, such as flour, bran, and shorts. Flour made from Fife wheat grown on the dry-farmsof Utah contained practically 16 per cent of protein, while flourmade from Fife wheat grown in Lorraine and the Middle West isreported by the Maine Station as containing from 13. 03 to 13. 75 percent of protein. Flour made from Blue Stem wheat grown on the Utahdry-farms contained 15. 52 per cent of protein; from the same varietygrown in Maine and in the Middle West 11. 69 and 11. 51 per cent ofprotein respectively. The moist and dry gluten, the gliadin and theglutenin, all of which make possible the best and most nourishingkinds of bread, are present in largest quantity and best proportionin flours made from wheats grown under typical dry-farm conditions. The by-products of the milling process, likewise, are rich innutritive elements. 

Future Needs

It has already been pointed out that there is a growing tendency topurchase food materials on the basis of composition. New discoveriesin the domains of plant composition and animal nutrition and theimproved methods of rapid and accurate valuation will acceleratethis tendency. Even now, manufacturers of food products print oncartons and in advertising matter quality reasons for the superiorfood values of certain articles. At least one firm produces twoparallel sets of its manufactured foods, one for the man who doeshard physical labor, and the other for the brain worker. Quality, asrelated to the needs of the body, whether of beast or man, israpidly becoming the first question in judging any food material. The present era of high prices makes this matter even moreimportant. 

In view of this condition and tendency, the fact that dry-farmproducts are unusually rich in the most valuable nutritive materialsis of tremendous importance to the development of dry-farming. Thesmall average yields of dry-farm crops do not look so small when itis known that they command higher prices per pound in competitionwith the larger crops of more humid climates. More elaborateinvestigations should be undertaken to determine the quality ofcrops grown in different dry-farm districts. As far as possible eachsection, great or small, should confine itself to the growing of avariety of each crop yielding well and possessing the highestnutritive value. In that manner each section of the great dry-farmterritory would soon come to stand for some dependable specialquality that would compel a first-class market. Further, thesuperior feeding value of dry-farm products should be thoroughlyadvertised among the consumers in order to create a demand on themarkets for a quality valuation. A few years of such systematichonest work would do much to improve the financial basis ofdry-farming. 

CHAPER XIV

MAINTAINING THE SOIL FERTILITY

All plants when carefully burned leave a portion of ash, rangingwidely in quantity, averaging about 5 per cent, and often exceeding10 per cent of the dry weight of the plant. This plant ashrepresents inorganic substances taken from the soil by the roots. Inaddition, the nitrogen of plants, averaging about 2 per cent andoften amounting to 4 per cent, which, in burning, passes off ingaseous form, is also usually taken from the soil by the plantroots. A comparatively large quantity of the plant is, therefore, drawn directly from the soil. Among the ash ingredients are manywhich are taken up by the plant simply because they are present inthe soil; others, on the other hand, as has been shown by numerousclassical investigations, are indispensable to plant growth. If anyone of these indispensable ash ingredients be absent, it isimpossible for a plant to mature on such a soil. In fact, it ispretty well established that, providing the physical conditions andthe water supply are satisfactory, the fertility of a soil dependslargely upon the amount of available ash ingredients, or plant-food. 

A clear distinction must be made between the_ total _and _available_plant-food. The essential plant-foods often occur in insolublecombinations, valueless to plants; only the plant-foods that aresoluble in the soil-water or in the juices of plant roots are ofvalue to plants. It is true that practically all soils contain allthe indispensable plant-foods; it is also true, however, that inmost soils they are present, as available plant-foods, incomparatively small quantities. When crops are removed from the landyear after year, without any return being made, it naturally followsthat under ordinary conditions the amount of available plant-food isdiminished, with a strong probability of a corresponding diminutionin crop-producing power. In fact, the soils of many of the oldercountries have been permanently injured by continuous cropping, withnothing returned, practiced through centuries. Even in many of theyounger states, continuous cropping to wheat or other crops for ageneration or less has resulted in a large decrease in the cropyield. 

Practice and experiment have shown that such diminishing fertilitymay be retarded or wholly avoided, first, by so working orcultivating the soil as to set free much of the insoluble plant-foodand, secondly, by returning to the soil all or part of theplant-food taken away. The recent development of the commercialfertilizer industry is a response to this truth. It may be saidthat, so far as the agricultural soils of the world are now known, only three of the essential plant-foods are likely to be absent, namely, potash, phosphoric acid, and nitrogen; of these, by far themost important is nitrogen. The whole question of maintaining thesupply of plant-foods in the soil concerns itself in the main withthe supply of these three substances. 

The persistent fertility of dry-farms

In recent years, numerous farmers and some investigators have statedthat under dry-farm conditions the fertility of soils is notimpaired by cropping without manuring. This view has been takenbecause of the well-known fact that in localities where dry-farminghas been practiced on the same soils from twenty-five to forty-fiveyears, without the addition of manures, the average crop yield hasnot only failed to diminish, but in most cases has increased. Infact, it is the almost unanimous testimony of the oldest dry-farmersof the United States, operating under a rainfall from twelve totwenty inches, that the crop yields have increased as the culturalmethods have been perfected. If any adverse effect of the steadyremoval of plant-foods has occurred, it has been wholly overshadowedby other factors. The older dry-farms in Utah, for instance, whichare among the oldest of the country, have never been manured, yetare yielding better to-day than they did a generation ago. Strangelyenough, this is not true of the irrigated farms, operating underlike soil and climatic conditions. This behavior of crop productionunder dry-farm conditions has led to the belief that the question ofsoil fertility is not an important one to dry-farmers. Nevertheless, if our present theories of plant nutrition are correct, it is alsotrue that, if continuous cropping is practiced on our dry-farm soilswithout some form of manuring, the time must come when theproductive power of the soils will be injured and the only recourseof the farmer will be to return to the soils some of the plant-foodtaken from it. 

The view that soil fertility is not diminished by dry-farmingappears at first sight to be strengthened by the results obtained byinvestigators who have made determinations of the actual plant-foodin soils that have long been dry-farmed. The sparsely settledcondition of the dry-farm territory furnishes as yet an excellentopportunity to compare virgin and dry-farmed lands and whichfrequently may be found side by side in even the older dry-farmsections. Stewart found that Utah dry-farm soils, cultivated forfifteen to forty years and never manured, were in many cases richerin nitrogen than neighboring virgin lands. Bradley found that thesoils of the great dry-farm wheat belt of Eastern Oregon contained, after having been farmed for a quarter of a century, practically asmuch nitrogen as the adjoining virgin lands. These determinationswere made to a depth of eighteen inches. Alway and Trumbull, on theother hand, found in a soil from Indian Head, Saskatchewan, that intwenty-five years of cultivation the total amount of nitrogen hadbeen reduced about one third, though the alternation of fallow andcrop, commonly practiced in dry-farming, did not show a greater lossof soil nitrogen than other methods of cultivation. It must be keptin mind that the soil of Indian Head contains from two to threetimes as much nitrogen as is ordinarily found in the soils of theGreat Plains and from three to four times as much as is found in thesoils of the Great Basin and the High Plateaus. It may be assumed, therefore, that the Indian Head soil was peculiarly liable tonitrogen losses. Headden, in an investigation of the nitrogencontent of Colorado soils, has come to the conclusion that aridconditions, like those of Colorado, favor the direct accumulation ofnitrogen in soils. All in all, the undiminished crop yield and thecomposition of the cultivated fields lead to the belief thatsoil-fertility problems under dry-farm conditions are widelydifferent from the old well-known problems under humid conditions. 

Reasons for dry-farming fertility

It is not really difficult to understand why the yields and, apparently, the fertility of dry-farms have continued to increaseduring the period of recorded dry-farm history--nearly half acentury. 

First, the intrinsic fertility of arid as compared with humid soilsis very high. (See Chapter V. ) The production and removal of manysuccessive bountiful crops would not have as marked an effect onarid as on humid soils, for both yield and composition change moreslowly on fertile soils. The natural extraordinarily high fertilityof dry-farm soils explains, therefore, primarily and chiefly, theincreasing yields on dry-farm soils that receive proper cultivation. 

The intrinsic fertility of arid soils is not alone sufficient toexplain the increase in plant-food which undoubtedly occurs in theupper foot or two of cultivated dry-farm lands. In seeking asuitable explanation of this phenomenon it must be recalled that theproportion of available plant-food in arid soils is very uniform togreat depths, and that plants grown under proper dry-farm conditionsare deep rooted and gather much nourishment from the lower soillayers. As a consequence, the drain of a heavy crop does not fallupon the upper few feet as is usually the case in humid soils. Thedry-farmer has several farms, one upon the other, which permit evenimproper methods of farming to go on longer than would be the caseon shallower soils. 

The great depth of arid soils further permits the storage of rainand snow water, as has been explained in previous chapters, todepths of from ten to fifteen feet. As the growing season proceeds, this water is gradually drawn towards the surface, and with it muchof the plant-food dissolved by the water in the lower soil layers. This process repeated year after year results in a concentration inthe upper soil layers of fertility normally distributed in the soilto the full depth reach by the soil-moisture. At certain seasons, especially in the fall, this concentration may be detected withgreatest certainty. In general, the same action occurs in virginlands, but the methods of dry-farm cultivation and cropping whichpermit a deeper penetration of the natural precipitation and a freermovement of the soil-water result in a larger quantity of plant-foodreaching the upper two or three feet from the lower soil depths. Such concentration near the surface, when it is not excessive, favors the production of increased yields of crops. 

The characteristic high fertility and great depth of arid soils areprobably the two main factors explaining the apparent increase ofthe fertility of dry-farms under a system of agriculture which doesnot include the practice of manuring. Yet, there are otherconditions that contribute largely to the result. For instance, every cultural method accepted in dry-farming, such as deep plowing, fallowing, and frequent cultivation, enables the weathering forcesto act upon the soil particles. Especially is it made easy for theair to enter the soil. Under such conditions, the plant-foodunavailable to plants because of its insoluble condition isliberated and made available. The practice of dry-farming is ofitself more conducive to such accumulation of available plant foodthan are the methods of humid agriculture. 

Further, the annual yield of any crop under conditions ofdry-farming is smaller than under conditions of high rainfall. Lessfertility is, therefore, removed by each crop and a given amount ofavailable fertility is sufficient to produce a large number of cropswithout showing signs of deficiency. The comparatively small annualyield of dry-farm crops is emphasized in view of the common practiceof summer fallowing, which means that the land is cropped only everyother year or possibly two years out of three. Under such conditionsthe yield in any one year is cut in two to give an annual yield. 

The use of the header wherever possible in harvesting dry-farm grainalso aids materially in maintaining soil fertility. By means of theheader only the heads of the grain are clipped off: the stalks areleft standing. In the fall, usually, this stubble is plowed underand gradually decays. In the earlier dry-farm days farmers fearedthat under conditions of low rainfall, the stubble or straw plowedunder would not decay, but would leave the soil in a loose drycondition unfavorable for the growth of plants. During the lastfifteen years it has been abundantly demonstrated that if thecorrect methods of dry farming are followed, so that a fair balanceof water is always found in the soil, even in the fall, the heavy, thick header stubble may be plowed into the soil with the certaintythat it will decay and thus enrich the soil. The header stubblecontains a very large proportion of the nitrogen that the crop hastaken from the soil and more than half of the potash and phosphoricacid. Plowing under the header stubble returns all this material tothe soil. Moreover, the bulk of the stubble is carbon taken from theair. This decays, forming various acid substances which act on thesoil grains to set free the fertility which they contain. At the endof the process of decay humus is formed, which is not only astorehouse of plant-food, but effective in maintaining a goodphysical condition of the soil. The introduction of the header indry-farming was one of the big steps in making the practice certainand profitable. 

Finally, it must be admitted that there are a great many more orless poorly understood or unknown forces at work in all soils whichaid in the maintenance of soil-fertility. Chief among these are thelow forms of life known as bacteria. Many of these, under favorableconditions, appear to have the power of liberating food from theinsoluble soil grains. Others have the power when settled on theroots of leguminous or pod-bearing plants to fix nitrogen from theair and convert it into a form suitable for the need of plants. Inrecent years it has been found that other forms of bacteria, thebest known of which is azotobacter, have the power of gatheringnitrogen from the air and combining it for the plant needs withoutthe presence of leguminous plants. These nitrogen-gathering bacteriautilize for their life processes the organic matter in the soil, such as the decaying header stubble, and at the same time enrich thesoil by the addition of combined nitrogen. Now, it so happens thatthese important bacteria require a soil somewhat rich in lime, wellaerated and fairly dry and warm. These conditions are all met on thevast majority of our dry-farm soils, under the system of cultureoutlined in this volume. Hall maintains that to the activity ofthese bacteria must be ascribed the large quantities of nitrogenfound in many virgin soils and probably the final explanation of thesteady nitrogen supply for dry farms is to be found in the work ofthe azatobacter and related forms of low life. The potash andphosphoric acid supply can probably be maintained for ages by propermethods of cultivation, though the phosphoric acid will becomeexhausted long before the potash. The nitrogen supply, however, mustcome from without. The nitrogen question will undoubtedly soon bethe one before the students of dry-farm fertility. A liberal supplyof organic matter In the soil with cultural methods favoring thegrowth of the nitrogen-gathering bacteria appears at present to bethe first solution of the nitrogen question. Meanwhile, the activityof the nitrogen-gathering bacteria, like azotobacter, is one of ourbest explanations of the large presence of nitrogen in cultivateddry-farm soils. 

To summarize, the apparent increase in productivity and plant-foodcontent of dry-farm soils can best be explained by a considerationof these factors: (1) the intrinsically high fertility of the aridsoils; (2) the deep feeding ground for the deep root systems ofdry-farm crops; (3) the concentration of the plant food distributedthroughout the soil by the upward movement of the naturalprecipitation stored in the soil; (4) the cultural methods ofdry-farming which enable the weathering agencies to liberate freelyand vigorously the plant-food of the soil grains; (5) the smallannual crops; (6) the plowing under of the header straw, and (7) theactivity of bacteria that gather nitrogen directly from the air. 

Methods of conserving soil-fertility

In view of the comparatively small annual crops that characterizedry-farming it is not wholly impossible that the factors abovediscussed, if properly applied, could liberate the latent plant-foodof the soil and gather all necessary nitrogen for the plants. Suchan equilibrium, could it once be established, would possiblycontinue for long periods of time, but in the end would no doubtlead to disaster; for, unless the very cornerstone of modernagricultural science is unsound, there will be ultimately adiminution of crop producing power if continuous cropping ispracticed without returning to the soil a goodly portion of theelements of soil fertility taken from it. The real purpose of modernagricultural researeh is to maintain or increase the productivity ofour lands; if this cannot be done, modern agriculture is essentiallya failure. Dry-farming, as the newest and probably in the future oneof the greatest divisions of modern agriculture, must from thebeginning seek and apply processes that will insure steadiness inthe productive power of its lands. Therefore, from the verybeginning dry-farmers must look towards the conservation of thefertility of their soils. 

The first and most rational method of maintaining the fertility ofthe soil indefinitely is to return to the soil everything that istaken from it. In practice this can be done only by feeding theproducts of the farm to live stock and returning to the soil themanure, both solid and liquid, produced by the animals. This bringsup at once the much discussed question of the relation between thelive stock industry and dry-farming. While it is undoubtedly truethat no system of agriculture will be wholly satisfactory to thefarmer and truly beneficial to the state, unless it is connecteddefinitely with the production of live stock, yet it must beadmitted that the present prevailing dry-farm conditions do notalways favor comfortable animal life. For instance, over a largeportion of the central area of the dry-farm territory the dry-farmsare at considerable distances from running or well water. In manycases, water is hauled eight or ten miles for the supply of the menand horses engaged in farming. Moreover, in these drier districts, only certain crops, carefully cultivated, will yield profitably, andthe pasture and the kitchen garden are practical impossibilitiesfrom an economic point of view. Such conditions, though profitabledry-farming is feasible, preclude the existence of the home and thebarn on or even near the farm. When feed must be hauled many miles, the profits of the live stock industry are materially reduced andthe dry-farmer usually prefers to grow a crop of wheat, the straw ofwhich may be plowed under the soil to the great advantage of thefollowing crop. In dry-farm districts where the rainfall is higheror better distributed, or where the ground water is near thesurface, there should be no reason why dry-farming and live stockshould not go hand in hand. Wherever water is within reach, thehomestead is also possible. The recent development of the gasolinemotor for pumping purposes makes possible a small home gardenwherever a little water is available. The lack of water for culinarypurposes is really the problem that has stood between the jointdevelopment of dry-farming and the live stock industry. The wholematter, however, looks much more favorable to-day, for the effortsof the Federal and state governments have succeeded in discoveringnumerous subterranean sources of water in dry-farm districts. Inaddition, the development of small irrigation systems in theneighborhood of dry-farm districts is helping the cause of the livestock industry. At the present time, dry-farming and the live stockindustry are rather far apart, though undoubtedly as the desert isconquered they will become more closely associated. The questionconcerning the best maintenance of soil-fertility remains the same;and the ideal way of maintaining fertility is to return to the soilas much as is possible of the plant-food taken from it by the crops, which can best be accomplished by the development of the business ofkeeping live stock in connection with dry-farming. 

If live stock cannot be kept on a dry-farm, the most direct methodof maintaining soil-fertility is by the application of commercialfertilizers. This practice is followed extensively in the Easternstates and in Europe. The large areas of dry-farms and the highprices of commercial fertilizers will make this method of manuringimpracticable on dry-farms, and it may be dismissed from thoughtuntil such a day as conditions, especially with respect to price ofnitrates and potash, are materially changed. 

Nitrogen, which is the most important plant-food that may be absentfrom dry-farm soils, may be secured by the proper use of leguminouscrops. All the pod-bearing plants commonly cultivated, such as peas, beans, vetch, clover, and lucern, are able to secure largequantities of nitrogen from the air through the activity of bacteriathat live and grow on the roots of such plants. The leguminous cropshould be sown in the usual way, and when it is well past theflowering stage should be plowed into the ground. Naturally, annuallegumes, such as peas and beans, should be used for this purpose. The crop thus plowed under contains much nitrogen, which isgradually changed into a form suitable for plant assimilation. Inaddition, the acid substances produced in the decay of the plantstend to liberate the insoluble plant-foods and the organic matter isfinally changed into humus. In order to maintain a proper supply ofnitrogen in the soil the dry-farmer will probably soon find himselfobliged to grow, every five years or oftener, a crop of legumes tobe plowed under. 

Non-leguminous crops may also be plowed under for the purpose ofadding organic matter and humus to the soil, though this has littleadvantage over the present method of heading the grain and plowingunder the high stubble. The header system should be generallyadopted on wheat dry-farms. On farms where corn is the chief crop, perhaps more importance needs to be given to the supply of organicmatter and humus than on wheat farms. The occasional plowing underof leguminous crops would he the most satisfactory method. Thepersistent application of the proper cultural methods of dry-farmingwill set free the most important plant-foods, and on well-cultivatedfarms nitrogen is the only element likely to be absent in seriousamounts. 

The rotation of crops on dry-farms is usually advocated in districtslike the Great Plains area, where the annual rainfall is overfifteen inches and the major part of the precipitation comes inspring and summer. The various rotations ordinarily include one ormore crops of small grains, a hoed crop like corn or potatoes, aleguminous crop, and sometimes a fallow year. The leguminous crop isgrown to secure a fresh supply of nitrogen; the hoed crop, to enablethe air and sunshine to act thoroughly on the soil grains and toliberate plant-food, such as potash and phosphoric acid; and thegrain crops to take up plant-food not reached by the root systems ofthe other plants. The subject of proper rotation of crops has alwaysbeen a difficult one, and very little information exists on it aspracticed on dry-farms. Chilcott has done considerable work onrotations in the Great Plains district, hut he frankly admits thatmany years of trial will he necessary for the elucidation oftrustworthy principles. Some of the best rotations found by Chilcottup to the present are:--

Corn--Wheat--OatsBarley--Oats--CornFallow--Wheat--Oats

Rosen states that rotation is very commonly practiced in the drysections of southern Russia, usually including an occasional Summerfallow. As a type of an eight-year rotation practiced at the PoltavaStation, the following is given: (1) Summer tilled and manured; (2)winter wheat; (3) hoed crop; (4) spring wheat; (5) summer fallow;(6) winter rye; (7) buckwheat or an annual legume; (8) oats. Thisrotation, it may be observed, includes the grain crop, hoed crop, legume, and fallow every four years. 

As has been stated elsewhere, any rotation in dry-farming which doesnot include the summer fallow at least every third or fourth year islikely to be dangerous In years of deficient rainfall. 

This review of the question of dry-farm fertility is intended merelyas a forecast of coming developments. At the present timesoil-fertility is not giving the dry-farmers great concern, but asin the countries of abundant rainfall the time will come when itwill be equal to that of water conservation, unless indeed thedry-farmers heed the lessons of the past and adopt from the startproper practices for the maintenance of the plant-food stored in thesoil. The principle explained in Chapter IX, that the amount ofwater required for the production of one pound of water diminishesas the fertility increases, shows the intimate relationship thatexists between the soil-fertility and the soil-water and theimportance of maintaining dry-farm soils at a high state offertility. 

CHAPTER XV

IMPLEMENTS FOR DRY-FARMING

Cheap land and relatively small acre yields characterizedry-farming. Consequently Iarger areas must be farmed for a givenreturn than in humid farming, and the successful pursuit ofdry-farming compels the adoption of methods that enable a man to dothe largest amount of effective work with the smallest expenditureof energy. The careful observations made by Grace, in Utah, lead tothe belief that, under the conditions prevailing in theintermountain country, one man with four horses and a sufficientsupply of machinery can farm 160 acres, half of which issummer-fallowed every year; and one man may, in favorable seasonsunder a carefully planned system, farm as much as 200 acres. If oneman attempts to handle a larger farm, the work is likely to be donein so slipshod a manner that the crop yield decreases and the totalreturns are no larger than if 200 acres had been well tilled. 

One man with four horses would be unable to handle even 160 acreswere it not for the possession of modern machinery; and dry-farming, more than any other system of agriculture, is dependent for itssuccess upon the use of proper implements of tillage. In fact, it isvery doubtful if the reclamation of the great arid and semiaridregions of the world would have been possible a few decades ago, before the invention and introduction of labor-saving farmmachinery. It is undoubtedly further a fact that the future ofdry-farming is closely bound up with the improvements that may bemade in farm machinery. Few of the agricultural implements on themarket to-day have been made primarily for dry-farm conditions. Thebest that the dry-farmer can do is to adapt the implements on themarket to his special needs. Possibly the best field ofinvestigation for the experiment stations and inventive minds in thearid region is farm mechanics as applied to the special needs ofdry-farming. 

Clearing and breaking

A large portion of the dry-farm territory of the United States iscovered with sagebrush and related plants. It is always a difficultand usually an expensive problem to clear sagebrush land, for theshrubs are frequently from two to six feet high, correspondinglydeep-rooted, with very tough wood. When the soil is dry, it isextremely difficult to pull out sagebrush, and of necessity much ofthe clearing must be done during the dry season. Numerous deviceshave been suggested and tried for the purpose of clearing sagebrushland. One of the oldest and also one of the most effective devicesis two parallel railroad rails connected with heavy iron chains andused as a drag over the sagebrush land. The sage is caught by thetwo rails and torn out of the ground. The clearing is fairlycomplete, though it is generally necessary to go over the ground twoor three times before the work is completed. Even after suchtreatment a large number of sagebrush clumps, found standing overthe field, must be grubbed up with the hoe. Another and effectivedevice is the so-called "mankiller. " This implement pulls up thesage very successfully and drops it at certain definite intervals. It is, however, a very dangerous implement and frequently results ininjury to the men who work it. Of recent years another device hasbeen tried with a great deal of success. It is made like a snow plowof heavy railroad irons to which a number of large steel knives havebeen bolted. Neither of these implements is wholly satisfactory, andan acceptable machine for grubbing sagebrush is yet to be devised. In view of the large expense attached to the clearing of sagebrushland such a machine would be of great help in the advancement ofdry-farming. 

Away from the sagebrush country the virgin dry-farm land is usuallycovered with a more or less dense growth of grass, though true sodis seldom found under dry-farm conditions. The ordinary breakingplow, characterized by a long sloping moldboard, is the best knownimplement for breaking all kinds of sod. (See Fig. 7a a. ) Where thesod is very light, as on the far western prairies, the more ordinaryforms of plows may be used. In still other sections, the dry-farmland is covered with a scattered growth of trees, frequently pinionpine and cedars, and in Arizona and New Mexico the mesquite tree andcacti are to be removed. Such clearing has to be done in accordancewith the special needs of the locality. 

Plowing

Plowing, or the turning over of the soil to a depth of from seven toten inches for every crop, is a fundamental operation ofdry-farming. The plow, therefore, becomes one of the most importantimplements on the dry-farm. Though the plow as an agriculturalimplement is of great antiquity, it is only within the last onehundred years that it has attained its present perfection. It is aquestion even to-day, in the minds of a great many students, whetherthe modern plow should not be replaced by some machine even moresuitable for the proper turning and stirring of the soil. Themoldboard plow is, everything considered, the most satisfactory plowfor dry-farm purposes. A plow with a moldboard possessing a shortabrupt curvature is generally held to be the most valuable fordry-farm purposes, since it pulverizes the soil most thoroughly, andin dry-farming it is not so important to turn the soil over as tocrumble and loosen it thoroughly. Naturally, since the areas ofdry-farms are very large, the sulky or riding plow is the only kindto be used. The same may be said of all other dry-farm implements. As far as possible, they should be of the riding kind since in theend it means economy from the resulting saving of energy. 

The disk plow has recently come into prominent use throughout theland. It consists, as is well known, of one or more large diskswhich are believed to cause a smaller draft, as they cut into theground, than the draft due to the sliding friction upon themoldboard. Davidson and Chase say, however, that the draft of a diskplow is often heavier in proportion to the work done and the plowitself is more clumsy than the moldboard plow. For ordinary dry-farmpurposes the disk plow has no advantage over the modern moldboardplow. Many of the dry-farm soils are of a heavy clay and become verysticky during certain seasons of the year. In such soils the diskplow is very useful. It is also true that dry-farm soils, subjectedto the intense heat of the western sun become very hard. In thehandling of such soils the disk plow has been found to be mostuseful. The common experience of dry-farmers is that when sagebrushlands have been the first plowing can be most successfully done withthe disk plow, but that after. The first crop has been harvested, the stubble land can be best handled with the moldboard plow. Allthis, however, is yet to be subjected to further tests. 

While subsoiling results in a better storage reservoir for water andconsequently makes dry-farming more secure, yet the high cost of thepractice will probably never make it popular. Subsoiling isaccomplished in two ways: either by an ordinary moldboard plow whichfollows the plow in the plow furrow and thus turns the soil to agreater depth, or by some form of the ordinary subsoil plow. Ingeneral, the subsoil plow is simply a vertical piece of cuttingiron, down to a depth of ten to eighteen inches, at the bottom ofwhich is fastened a triangular piece of iron like a shovel, which, when pulled through the ground, tends to loosen the soil to the fulldepth of the plow. 

The subsoil plow does not turn the soil; it simply loosens the soilso that the air and plant roots can penetrate to greater depths. 

In the choice of plows and their proper use the dryfarmer must beguided wholly by the conditions under which he is working. It isimpossible at the present time to lay down definite laws statingwhat plows are best for certain soils. The soils of the arid regionare not well enough known, nor has the relationship between the plowand the soil been sufficiently well established. As above remarked, here is one of the great fields for investigation for bothscientific and practical men for years to come. 

Making and maintaining a soil-mulch

After the land has been so well plowed that the rains can entereasily, the next operation of importance in dry-farming is themaking and maintaining of a soil-mulch over the ground to preventthe evaporation of water from the soil. For this purpose some formof harrow is most commonly used. The oldest and best-known harrow isthe ordinary smoothing harrow, which is composed of iron or steelteeth of various shapes set in a suitable frame. (See Fig. 79. ) Fordry-farm purposes the implement must be so made as to enable thefarmer to set the harrow teeth to slant backward or forward. Itfrequently happens that in the spring the grain is too thick for themoisture in the soil, and it then becomes necessary to tear out someof the young plants. For this purpose the harrow teeth are setstraight or forward and the crop can then be thinned effectively. Atother times it may be observed in the spring that the rains andwinds have led to the formation of a crust over the soil, which mustbe broken to let the plants have full freedom of growth anddevelopment. This is accomplished by slanting the harrow teethbackward, and the crust may then be broken without serious injury tothe plants. The smoothing harrow is a very useful implement on thedry-farm. For following the plow, however, a more useful implementis the disk harrow, which is a comparatively recent invention. Itconsists of a series of disks which may be set at various angleswith the line of traction and thus be made to turn over the soilwhile at the same time pulverizing it. The best dry-farm practice isto plow in the fall and let the soil lie in the rough during thewinter months. In the spring the land is thoroughly disked andreduced to a fine condition. Following this the smoothing harrow isoccasionally used to form a more perfect mulch. When seeding is tobe done immediately after plowing, the plow is followed by the diskharrow, and that in turn is followed by the smoothing harrow. Theground is then ready for seeding. The disk harrow is also usedextensively throughout the summer in maintaining a proper mulch. Itdoes its work more effectively than the ordinary smoothing harrowand is, therefore, rapidly displacing all other forms of harrows forthe purpose of maintaining a layer of loose soil over the dry-farm. There are several kinds of disk harrows used by dry-farmers. Thefull disk is, everything considered, the most useful. The cutawayharrow is often used in cultivating old alfalfa land; the spade diskharrow has a very limited application in dry-farming; and theorchard disk harrow is simply a modlfication of the full disk harrowwhereby the farmer is able to travel between the rows of trees andso to cultivate the soil under the branches of the trees withoutinjuring the leaves or fruit. 

One of the great difficulties in dry-farming concerns itself withthe prevention of the growth of weeds or volunteer crops. As hasbeen explained in previous chapters, weeds require as much water fortheir growth as wheat or other useful crops. During the fallowseason, the farmer is likely to be overtaken by the weeds and losemuch of the value of the fallow by losing soil-moisture through thegrowth of weeds. Under the most favorable conditions weeds aredifficult to handle. The disk harrow itself is not effective. Thesmoothing harrow is of less value. There is at the present timegreat need for some implement that will effectively destroy youngweeds and prevent their further growth. Attempts are being made toinvent such implements, but up to the present without great success. Hogenson reports the finding of an implement on a western dry-farmconstructed by the farmer himself which for a number of years hasshown itself of high efficiency in keeping the dry-farm free fromweeds. Several improved modifications of this implement have beenmade and tried out on the famous dry-farm district at Nephi, Utah, and with the greatest success. Hunter reports a similar implement incommon use on the dry-farms of the Columbia Basin. Spring toothharrows are also used in a small way on the dry-farms. 

They have no special advantage over the smoothing harrow or the diskharrow, except in places where the attempt is made to cultivate thesoil between the rows of wheat. The curved knife tooth harrow isscareely ever used on dry-farms. It has some value as a pulverizer, but does not seem to have any real advantage over the ordinary diskharrow. 

Cultivators for stirring the land on which crops are growing are notused extensively on dry-farms. Usually the spring tooth harrow isemployed for this work. In dry-farm sections, where corn is grown, the cultivator is frequently used throughout the season. Potatoesgrown on dry-farms should be cultivated throughout the season, andas the potato industry grows in the dry-farm territory there will bea greater demand for suitable cultivators. The cultivators to beused on dry-farms are all of the riding kind. They should be soarranged that the horse walking between two rows carries acultivator that straddles several rows of plants and cultivates thesoil between. Disks, shovels, or spring teeth may be used oncultivators. There is a great variety on the market, and each farmerwill have to choose such as meet most definitely his needs. 

The various forms of harrows and cultivators are of the greatestimportance in the development of dry-farming. Unless a proper mulchcan be kept over the soil during the fallow season, and as far aspossible during the growing season, first-class crops cannot befully respected. 

The roller is occasionally used in dry-farming, especially in theuplands of the Columbia Basin. It is a somewhat dangerous implementto use where water conservation is important, since the packingresulting from the roller tends to draw water upward from the lowersoil layers to be evaporated into the air. Wherever the roller isused, therefore, it should be followed immediately by a harrow. Itis valuable chiefly in the localities where the soil is very looseand light and needs packing around the seeds to permit perfectgermination. 

Subsurface packing

The subsurface packer invented by Campbell is [shown in Figure83--not shown--ed. ]. The wheels of this machine eighteen inches indiameter, with rims one inch thick at the inner part, beveled twoand a half inches to a sharp outer edge, are placed on a shaft, fiveinches apart. In practice about five hundred pounds of weight areadded. 

This machine, according to Campbell, crowds a one-inch wedge intoevery five inches of soil with a lateral and a downward pressure andthus packs firmly the soil near the bottom of the plow-furrow. Subsurface packing aims to establish full capillary connectionbetween the plowed upper soil and the undisturbed lower soil-layer;to bring the moist soil in close contact with the straw or organiclitter plowed under and thus to hasten decomposition, and to providea firm seed bed. 

The subsurface packer probably has some value where the plowed soilcontaining the stubble is somewhat loose; or on soils which do notpermit of a rapid decay of stubble and other organic matter that maybe plowed under from season to season. On such soils the packingtendency of the subsurface packer may help prevent loss of soilwater, and may also assist in furnishing a more uniform mediumthrough which plant roots may force their way. For all thesepurposes, the disk is usually equally efficient. 

Sowing

It has already been indicated in previous chapters that propersowing is one of the most important operations of the dry-farm, quite comparable in importance with plowing or the maintaining of amulch for retaining soil-moisture. The old-fashioned method ofbroadcasting has absolutely no place on a dry-farm. The success ofdry-farming depends entirely upon the control that the farmer has ofall the operations of the farm. By broadcasting, neither thequantity of seed used nor the manner of placing the seed in theground can be regulated. Drill culture, therefore, introduced byJethro Tull two hundred years ago, which gives the farmer fullcontrol over the process of seeding, is the only system to be used. The numerous seed drills on the market all employ the sameprinciples. Their variations are few and simple. In all seed drillsthe seed is forced into tubes so placed as to enable the seed tofall into the furrows in the ground. The drills themselves aredistinguished almost wholly by the type of the furrow opener and thecovering devices which are used. The seed furrow is opened either bya small hoe or a so-called shoe or disk. At the present time itappears that the single disk is the coming method of opening theseed furrow and that the other methods will gradually disappear. Asthe seed is dropped into the furrow thus made it is covered by somedevice at the rear of the machine. One of the oldest methods as wellas one of the most satisfactory is a series of chains draggingbehind the drill and covering the furrow quite completely. It is, however, very desirable that the soil should be pressed carefullyaround the seed so that germination may begin with the leastdifficulty whenever the temperature conditions are right. Most ofthe drills of the day are, therefore, provided with large lightwheels, one for each furrow, which press lightly upon the soil andforce the soil into intimate contact with the seed The weakness ofsuch an arrangement is that the soil along the drill furrows is leftsomewhat packed, which leads to a ready escape of the soil-moisture. Many of the drills are so arranged that press wheels may be used atthe pleasure of the farmer. The seed drill is already a very usefulimplement and is rapidly being made to meet the special requirementsof the dry-farmer. Corn planters are used almost exclusively ondry-farms where corn is the leading crop. In principle they are verymuch the same as the press drills. Potatoes are also generallyplanted by machinery. Wherever seeding machinery has beenconstructed based upon the principles of dry-farming, it is a veryadvantageous adjunct to the dry-farm. 

Harvesting

The immense areas of dry-farms are harvested almost wholly by themost modern machinery. For grain, the harvester is used almostexclusively in the districts where the header cannot be used, butwherever conditions permit, the header is and should be used. It hasbeen explained in previous chapters how valuable the tall headerstubble is when plowed under as a means of maintaining the fertilityof the soil. Besides, there is an ease in handling the header whichis not known with the harvester. There are times when the headerleads to some waste as, for instance, when the wheat is very low andheads are missed as the machine passes over the ground. In manysections of the dry-farm territory the climatic conditions are suchthat the wheat cures perfectly while still standing. In such placesthe combined harvester and thresher is used. The header cuts off theheads of the grain, which are passed up into the thresher, and bagsfilled with threshed grain are dropped along the path of themachine, while the straw is scattered over the ground. Wherever sucha machine can be used, it has been found to be economical andsatisfactory. Of recent years corn stalks have been used to betteradvantage than in the past, for not far from one half of the feedingvalue of the corn crop is in the stalks, which up to a few years agowere very largely wasted. Corn harvesters are likewise on the marketand are quite generally used. It was manifestly impossible on largeplaces to harvest corn by hand and large corn harvesters have, therefore, been made for this purpose. 

Steam and other motive power

Recently numerous persons have suggested that the expense of runninga dry-farm could be materially reduced by using some motive powerother than horses. Steam, gasoline, and electricity have all beensuggested. The steam traction engine is already a fairlywell-developed machine and it has been used for plowing purposes onmany dry-farms in nearly all the sections of the dry-farm territory. Unfortunately, up to the present it has not shown itself to be verysatisfactory. First of all it is to be remembered that theprinciples of dry-farming require that the topsoil be kept veryloose and spongy. The great traction engines have very wide wheelsof such tremendous weight that they press down the soil verycompactly along their path and in that way defeat one of theimportant purposes of tillage. Another objection to them is that atpresent their construction is such as to result in continualbreakages. While these breakages in themselves are small andinexpensive, they mean the cessation of all farming operationsduring the hour or day required for repairs. A large crew of men isthus left more or less idle, to the serious injury of the work andto the great expense of the owner. Undoubtedly, the traction enginehas a place in dry-farming, but it has not yet been perfected tosuch a degree as to make it satisfactory. On heavy soils it is muchmore useful than on light soils. When the traction engine workssatisfactorily, plowing may be done at a cost considerably lowerthan when horses are employed. 

In England, Germany, and other European countries some of thedifficulties connected with plowing have been overcome by using twoengines on the two opposite sides of a field. These engines movesynchronously together and, by means of large cables, plows, harrows, or seeders, are pulled back and forth over the field. Thismethod seems to give good satisfaction on many large estates of theold world. Macdonald reports that such a system is in successfuloperation in the Transvaal in South Africa and is doing work thereat a very knew cost. The large initial cost of such a system will, of course, prohibit its use except on the very large farms that arebeing established in the dry-farm territory. 

Gasoline engines are also being tried out, but up to date they havenot shown themselves as possessing superior advantages over thesteam engines. The two objections to them are the same as to thesteam engine: first, their great weight, which compresses in adangerous degree the topsoil and, secondly, the frequent breakages, which make the operation slow and expensive. 

Over a great part of the West, water power is very abundant and thesuggestion has been made that the electric energy which can bedeveloped by means of water power could be used in the culturaloperations of the dry-farm. With the development of the trolley carwhich does not run on rails it would not seem impossible that infavorable localities electricity could be made to serve the farmerin the mechanical tillage of the dry-farm. 

The substitution of steam and other energy for horse power is yet inthe future. Undoubtedly, it will come, but only as improvements aremade in the machines. There is here also a great field for being ofhigh service to the farmers who are attempting to reclaim the greatdeserts of the world. As stated at the beginning of this chapter, dry-farming would probably have been an impossibilityfifty or ahundred years ago because of the absence of suitable machinery. Thefuture of dry-farming rests almost wholly, so far as its profits areconcerned, upon the development of new and more suitable machineryfor the tillage of the soil in accordance with the establishedprinciples of dry-farming. 

Finally, the recommendations made by Merrill may here be inserted. Adry-farmer for best work should be supplied with the followingimplements in addition to the necessary wagons and hand tools:--

One Plow. One Disk. One Smoothing Harrow. One Drill Seeder. One Harvester or Header. One Mowing Machine. 

CHAPTER XVI

IRRIGATION AND DRY-FARMING

Irrigation-farming and dry-farming are both systems of agriculturedevised for the reclamation of countries that ordinarily receive anannual rainfall of twenty inches or less. Irrigation-farming cannotof itself reclaim the arid regions of the world, for the availablewater supply of arid countries when it shall have been conserved inthe best possible way cannot be made to irrigate more than one fifthof the thirsty land. This means that under the highest possibledevelopment of irrigation, at least in the United States, there willbe five or six acres of unirrigated or dry-farm land for every acreof irrigated land. Irrigation development cannot possibly, therefore, render the dry-farm movement valueless. On the otherhand, dry-farming is furthered by the development of irrigationfarming, for both these systems of agriculture are characterized byadvantages that make irrigation and dry-farming supplementary toeach other in the successful development of any arid region. 

Under irrigation, smaller areas need to be cultivated for the samecrop returns, for it has been amply demonstrated that the acreyields under proper irrigation are very much larger than the bestyields under the most careful system of dry-farming. Secondly, agreater variety of crops may be grown on the irrigated farm than onthe dry-farm. As has already been shown in this volume, only certaindrouth resistant crops can be grown profitably upon dry-farms, andthese must be grown under the methods of extensive farming. Thelonger growing crops, including trees, succulent vegetables, and avariety of small fruits, have not as yet been made to yieldprofitably under arid conditions without the artificial applicationof water. Further, the irrigation-farmer is not largely dependentupon the weather and, therefore, carries on this work with a feelingof greater security. Of course, it is true that the dry years affectthe flow of water in the canals and that the frequent breaking ofdams and canal walls leaves the farmer helpless in the face of theblistering heat. Yet, all in all, a greater feeling of security ispossessed by the irrigation farmer than by the dry-farmer. 

Most important, however, are the temperamental differences in menwhich make some desirous of giving themselves to the cultivation ofa small area of irrigated land under intensive conditions and othersto dry-farming under extensive conditions. In fact, it is beingobserved in the arid region that men, because of their temperamentaldifferences, are gradually separating into the two classes ofirrigation-farmers and dry-farmers. The dry-farms of necessity covermuch larger areas than the irrigated farms. The land is cheaper andthe crops are smaller. The methods to be applied are those ofextensive farming. The profits on the investment also appear to besomewhat larger. The very necessity of pitting intellect against thefierceness of the drouth appears to have attracted many-men to thedry-farms. Gradually the certainty of producing crops on dry-farmsfrom season to season is becoming established, and the essentialdifference between the two kinds of farming in the arid districtswill then he the difference between intensive and extensive methodsof culture. Men will be attracted to one or other of these systemsof agriculture according to their personal inclinations. 

The scarcity of water

For the development of a well-rounded commonwealth in an arid regionit is, of course, indispensable that irrigation be practiced, fordry-farming of itself will find it difficult to build up populouscities and to supply the great variety of crops demanded by themodern family. In fact, one of the great problems before thoseengaged in the development of dry-farming at present is thedevelopment of homesteads in the dry-farms. A homestead is possibleonly where there is a sufficient amount of free water available forhousehold and stock purposes. In the portion of the dry-farmterritory where the rainfall approximates twenty inches, thisproblem is not so very difficult, since ground water may be reachedeasily. In the drier portions, however, where the rainfall isbetween ten and fifteen inches, the problem is much more important. The conditions that bring the district under the dry-farmdesignation imply a scarcity of water. On few dry-farms is wateravailable for the needs of the household and the barns. In the RockyMountain states numerous dry-farms have been developed from seven tofifteen miles from the nearest source of water, and the main expenseof developing these farms has been the hauling of water to the farmsto supply the needs of the men and beasts at work on them. Naturally, it is impossible to establish homesteads on the dry-farmsunless at least a small supply of water is available; anddry-farming will never he what it might be unless happy homes can beestablished upon the farms in the arid regions that grow cropswithout irrigation. To make a dry-farm homestead possible enoughwater must be available, first of all, to supply the culinary needsof the household. This of itself is not large and, as will be shownhereafter, may in most cases be obtained. However, in order that thefamily may possess proper comforts, there should be around thehomestead trees, and shrubs, and grasses, and the family garden. Tosecure these things a certain amount of irrigation water isrequired. It may be added that dry-farms on which such homesteadsare found as a result of the existence of a small supply ofirrigation water are much more valuable, in case of sale, thanequally good farms without the possibility of maintaininghomesteads. Moreover, the distinct value of irrigation in producinga large acre yield makes it desirable for the farmer to use all thewater at his disposal for irrigation purposes. No available watershould be allowed to flow away unused. 

Available surface water

The sources of water for dry-farms fall readily into classes:surface waters and subterranean waters. The surface waters, whereverthey may be obtained, are generally the most profitable. Thesimplest method of obtaining water in an irrigated region is fromsome irrigation canal. In certain districts of the intermountainregion where the dry farms lie above the irrigation canals and theirrigated lands below, it is comparatively easy for the farmers tosecure a small but sufficient amount of water from the canal by theuse of some pumping device that will force the water through thepipes to the homestead. The dry-farm area that may be so supplied byirrigation canals is, however, very limited and is not to beconsidered seriously in connection with the problem. 

A much more important method, especially in the mountainousdistricts, is the utilization of the springs that occur in greatnumbers over the whole dry-farm territory. Sometimes these springsare very small indeed, and often, after development by tunnelinginto the side of the hill, yield only a trifling flow. Yet, whenthis water is piped to the homestead and allowed to accumulate insmall reservoirs or cisterns, it may be amply sufficient for theneeds of the family and the live stock, besides having a surplus forthe maintenance of the lawn, the shade trees, and the family garden. Many dry-farmers in the intermountain country have piped water sevenor eight miles from small springs that were considered practicallyworthless and thereby have formed the foundations for small villagecommunities. 

Of perhaps equal importance with the utilization of the naturallyoccurring springs is the proper conservation of the flood waters. Ashas been stated before, arid conditions allow a very large loss ofthe natural precipitation as run-off. The numerous gullies thatcharacterize so many parts of the dry-farm territory are evidencesof the number and vigor of the flood waters. The construction ofsmall reservoirs in proper places for the purpose of catching theflood waters will usually enable the farmer to supply himself withall the water needed for the homestead. Such reservoirs may alreadybe found in great numbers scattered over the whole western America. As dry-farming increases their numbers will also increase. 

When neither canals, nor springs, nor flood waters are available forthe supply of water, it is yet possible to obtain a limited supplyby so arranging the roof gutters on the farm buildings that all thewater that falls on the roofs is conducted through the spouts intocarefully protected cisterns or reservoirs. A house thirty by thirtyfeet, the roof of which is so constructed that all that water thatfalls upon it is carried into a cistern will yield annually under aa rainfall of fifteen inches a maximum amount of water equivalent toabout 8800 gallons. Allowing for the unavoidable waste due toevaporation, this will yield enough to supply a household and somelive stock with the necessary water. In extreme cases this has beenfound to be a very satisfactory practice, though it is the one to beresorted to only in case no other method is available. 

It is indispensable that some reservoir be provided to hold thesurface water that may be obtained until the time it may be needed. The water coming constantly from a spring in summer should beapplied to crops only at certain definite seasons of the year. Theflood waters usually come at a time when plant growth is not activeand irrigation is not needed. 

The rainfall also in many districts comes most largely at seasons ofno or little plant growth. Reservoirs must, therefore, be providedfor the storing of the water until the periods when it is demandedby crops. Cement-lined cisterns are quite common, and in many placescement reservoirs have been found profitable. In other places theoccurrence of impervious clay has made possible the establishmentand construction of cheap reservoirs. The skillful and permanentconstruction of reservoirs is a very important subject. Reservoirbuilding should be undertaken only after a careful study of theprevailing conditions and under the advice of the state orgovernment officials having such work in charge. In general, thefirst cost of small reservoirs is usually somewhat high, but in viewof their permanent service and the value of the water to thedry-farm they pay a very handsome interest on the investment. It isalways a mistake for the dry-farmer to postpone the construction ofa reservoir for the storing of the small quantities of water that hemay possess, in order to save a little money. Perhaps the greatestobjection to the use of the reservoirs is not their relatively highcost, but the fact that since they are usually small and the watershallow, too large a proportion of the water, even under favorableconditions, is lost by evaporation. It is ordinarily assumed thatone half of the water stored in small reservoirs throughout the yearis lost by direct evaporation. 

Available subterranean water

Where surface waters are not readily available, the subterraneanwater is of first importance. It is generally known that, underlyingthe earth's surface at various depths, there is a large quantity offree water. Those living in humid climates often overestimate theamount of water so held in the earth's crust, and it is probablytrue that those living in arid regions underestimate the quantity ofwater so found. The fact of the matter seems to be that free wateris found everywhere under the earth's surface. Those familiar withthe arid West have frequently been surprised by the frequency withwhich water has been found at comparatively shallow depths in themost desert locations. Various estimates have been made as to thequantity of underlying water. The latest calculation and perhaps themost reliable is that made by Fuller, who, after a careful analysisof the factors involved, concludes that the total free water held inthe earth's crust is equivalent to a uniform sheet of water over theentire surface of the earth ninety-six feet in depth. A quantity ofwater thus held would be equivalent to about one hundredth part ofthe whole volume of the ocean. Even though the thickness of thewater sheet under arid soils is only half this figure there is anamount, if it could be reached, that would make possible theestablishment of homesteads over the whole dry-farm territory. Oneof the main efforts of the day is the determination of theoccurrence of the subterranean waters in the dry-farm territory. 

Ordinary dug wells frequently reach water at comparatively shallowdepths. Over the cultivated Utah deserts water is often found at adepth of twenty-five or thirty feet, though many wells dug to adepth of one hundred and seventy-five and two hundred feet havefailed to reach water. It may be remarked in this connection thateven where the distance to the water is small, the piped well hasbeen found to be superior to the dug well. Usually, water isobtained in the dry-farm territory by driving pipes to comparativelygreat depths, ranging from one hundred feet to over one thousandfeet. At such depths water is nearly always found. Often thegeological conditions are such as to force the water up above thesurface as artesian wells, though more often the pressure is simplysufficient to bring the water within easy pumping distance of thesurface. In connection with this subject it must be said that manyof the subterranean waters of the dry-farm territory are of a salinecharacter. The amount of substances held in solution varies largely, but frequently is far above the limits of safety for the use of manor beast or plants. The dry-farmer who secures a well of this typeshould, therefore, be careful to have a proper examination made ofthe constituents of the water before ordinary use is made of it. 

Now, as has been said, the utilization of the subterranean waters ofthe land is one of the living problems of dry-farming. The tracingout of this layer of water is very difficult to accomplish andcannot be done by individuals. It is a work that properly belongs tothe state and national government. The state of Utah, which was thepioneer in appropriating money for dry-farm experiments, also ledthe way in appropriating money for the securing of water for thedry-farms from subterranean sources. The world has been progressingin Utah since 1905, and water has been secured in the mostunpromising localities. The most remarkable instance is perhaps thefinding of water at a depth of about five hundred and fifty feet inthe unusually dry Dog Valley located some fifteen miles west ofNephi. 

Pumping water

The use of small quantities of water on the dry-farms carries withit, in most cases, the use of small pumping plants to store and todistribute the water properly. Especially, whenever subterraneansources of water are used and the water pressure is not sufficientto throw the water above the ground, pumping must be resorted to. The pumping of water for agricultural purposes is not at all new. According to Fortier, two hundred thousand acres of land areirrigated with water pumped from driven wells in the state ofCalifornia alone. Seven hundred and fifty thousand acres areirrigated by pumping in the United States, and Mead states thatthere are thirteen million acres of land in India which areirrigated by water pumped from subterranean sources. The dry-farmerhas a choice among several sources of power for the operation of hispumping plant. In localities where winds are frequent and ofsufficient strength windmills furnish cheap and effective power, especially where the lift is not very great. The gasoline engine isin a state of considerable perfection and may be used economicallywhere the price of gasoline is reasonable. Engines using crude oilmay be most desirable in the localities where oil wells have beenfound. As the manufacture of alcohol from the waste products of thefarms becomes established, the alcohol-burning engine could become avery important one. Over nearly the whole of the dry-farm territorycoal is found in large quantities, and the steam engine fed by coalis an important factor in the pumping of water for irrigationpurposes. Further, in the mountainous part of the dry-farm territorywater Power is very abundant. Only the smallest fraction of it hasas yet been harnessed for the generation of the electric current. Aselectric generation increases, it should be comparatively easy forthe farmer to secure sufficient electric power to run the pump. Thishas already become an established practice in districts whereelectric power is available. 

During the last few years considerable work has been done todetermine the feasibility of raising water for irrigation bypumping. Fortier reports that successful results have been obtainedin Colorado, Wyoming, and Montana. He declares that a good type ofwindmill located in a district where the average wind movement isten miles per hour can lift enough water twenty feet to irrigatefive acres of land. Wherever the water is near the surface thisshould be easy of accomplishment. Vernon, Lovett, and Scott, whoworked under New Mexico conditions, have reported that crops can beproduced profitably by the use of water raised to the surface forirrigation. Fleming and Stoneking, who conducted very carefulexperiments on the subject in New Mexico, found that the cost ofraising through one foot a quantity of water corresponding to adepth of one foot over one acre of land varied from a cent and aneighth to nearly twenty-nine cents, with an average of a little morethan ten cents. This means that the cost of raising enough water tocover one acre to a depth of one foot through a distance of fortyfeet would average $4. 36. This includes not only the cost of thefuel and supervision of the pump but the actual deterioration of theplant. Smith investigated the same problem under Arizona conditionsand found that it cost approximately seventeen cents to raise oneacre foot of water to a height of one foot. A very elaborateinvestigation of this nature was conducted in California by Le Conteand Tait. They studied a large number of pumping plants in actualoperation under California conditions, and determined that the totalcost of raising one acre foot of water one foot was, for gasolinepower, four cents and upward; for electric power, seven to sixteencents, and for steam, four cents and upward. Mead has reportedobservations on seventy-two windmills near Garden City, Kansas, which irrigated from one fourth to seven acres each at a cost ofseventy-five cents to $6 per acre. All in all, these results justifythe belief that water may be raised profitably by pumping for thepurpose of irrigating crops. When the very great value of a littlewater on a dry-farm is considered, the figures here given do notseem at all excessive. It must be remarked again that a reservoir ofsome sort is practically indispensable in connection with a pumpingplant if the irrigation water is to be used in the best way. 

The use of small quantities of water in irrigation

Now, it is undoubtedly true that the acre cost of water ondry-farms, where pumping plants or similar devices must be used withexpensive reservoirs, is much higher than when water is obtainedfrom gravity canals. It is, therefore, important that the costlywater so obtained be used in the most economical manner. This isdoubly important in view of the fact that the water supply obtainedon dry-farms is always small and insufficient for all that thefarmer would like to do. Indeed, the profit in storing and pumpingwater rests largely upon the economical application of water tocrops. This necessitates the statement of one of the firstprinciples of scientific irrigation practices, namely, that theyield of a crop under irrigation is not proportional to the amountof water applied in the form of irrigation water. In other words, the water stored in the soil by the natural precipitation and thewater that falls during the spring and summer can either mature asmall crop or bring a crop near maturity. A small amount of wateradded in the form of irrigation water at the right time will usuallycomplete the work and produce a well-matured crop of large yield. Irrigation should only be supplemented to the natural precipitation. As more irrigation water is added, the increase in yield becomessmaller in proportion to the amount of water employed. This isclearly shown by the following table, which is taken from some ofthe irrigation experiments carried on at the Utah Station:--

Effect of Varying Irrigations on Crop Yields Per Acre

Depth of Water Wheat Corn Alfalfa Potatoes Sugar BeetsApplied (Inches) (Bushels) (Bushels) (Pounds) (Bushels) (Tons)5. 0 40 194 257. 5 41 6510. 0 41 80 213 2615. 0 46 78 253 2725. 0 49 77 10, 056 25835. 0 55 9, 142 291 2650 60 84 13, 061

The soil was a typical arid soil of great depth and had been socultivated as to contain a large quantity of the naturalprecipitation. The first five inches of water added to theprecipitation already stored in the soil produced forty bushels ofwheat. Doubling this amount of irrigation water produced onlyforty-one bushels of wheat. Even with an irrigation of fifty inches, or ten times that which produced forty bushels, only sixty bushelsof wheat, or an increase of one half, were produced. A similarvariation may be observed in the case of the other crops. The firstlesson to be drawn from this important principle of irrigation isthat if the soil be so treated as to contain at planting time thelargest proportion of the natural precipitation, --that is, if theordinary methods of dry-farming be employed, --crops will be producedwith a very small amount of irrigation water. Secondly, it followsthat it would be a great deal better for the farmer who raiseswheat, for instance, to cover ten acres of land with water to adepth of five inches than to cover one acre to a depth of fiftyinches, for in the former case four hundred bushels and in thesecond sixty bushels of wheat would be produced. The farmer whodesires to utilize in the most economical manner the small amount ofwater at his disposal must prepare the land according to dry-farmmethods and then must spread the water at his disposal over a largerarea of land. The land must be plowed in the fall if the conditionspermit, and fallowing should be practiced wherever possible. If thefarmer does not wish to fallow his family garden he can achieveequally good results by planting the rows twice as far apart as isordinarily the case and by bringing the irrigation furrows near therows of plants. Then, to make the best use of the water, he mustcarefully cover the irrigation furrow with dry dirt immediatelyafter the water has been applied and keep the whole surface wellstirred so that evaporation will be reduced to a minimum. Thebeginning of irrigation wisdom is always the storage of the naturalprecipitation. When that is done correctly, it is really remarkablehow far a small amount of irrigation water may be made to go. 

Under conditions of water scarcity it is often found profitable tocarry water to the garden in cement or iron pipes so that no watermay be lost by seepage or evaporation during the conveyance of thewater from the reservoir to the garden. It is also often desirableto convey water to plants through pipes laid under the ground, perforated at various intervals to allow the water to escape andsoak into the soil in the neighborhood of the plant roots. All suchrefined methods of irrigation should be carefully investigated bythe who wants the largest results from his limited water supply. Though such methods may seem cumbersome and expensive at first, yetthey will be found, if properly arranged, to be almost automatic intheir operation and also very profitable. 

Forbes has reported a most interesting experiment dealing with theeconomical use of a small water supply under the long season andintense water dissipating conditions of Arizona. The source ofsupply was a well, 90 feet deep. A 3 by 14-inch pump cylinderoperated by a 12-foot geared windmill lifted the water into a5000-gallon storage reservoir standing on a support 18 feet high. The water was conveyed from this reservoir through black iron pipesburied 1 or 2 feet from the trees to be watered. Small holes in thepipe 332 inch in diameter allowed the water to escape at desirableintervals. This irrigation plant was under expert observation forconsiderable time, and it was found to furnish sufficient water fordomestic use for one household, and irrigated in addition 61 olivetrees, 2 cottonwoods, 8 pepper trees, 1 date palm, 19 pomegranates, 4 grapevines, 1 fig tree, 9 eucalyptus trees, 1 ash, and 13miscellancous, making a total of 87 useful trees, mainlyfruit-bearing, and 32 vines and bushes. (See Fig. 95. ) If such aresult can be obtained with a windmill and with water ninety feetbelow the surface under the arid conditions of Arizona, there shouldbe little difficulty in securing sufficient water over the largerportions of the dry-farm territory to make possible beautifulhomesteads. 

The dry-farmer should carefully avoid the temptation to decryirrigation practices. Irrigation and dry-farming of necessity mustgo hand in hand in the development of the great arid regions of theworld. Neither can well stand alone in the building of greatcommonwealths on the deserts of the earth. 

CHAPTER XVII

THE HISTORY OF DRY-FARMING

The great nations of antiquity lived and prospered in arid andsemiarid countries. In the more or less rainless regions of China, Mesopotamia, Palestine, Egypt, Mexico, and Peru, the greatest citiesand the mightiest peoples flourished in ancient days. Of the greatcivilizations of history only that of Europe has rooted in a humidclimate. As Hilgard has suggested, history teaches that a highcivilization goes hand in hand with a soil that thirsts for water. To-day, current events point to the arid and semiarid regions as thechief dependence of our modern civilization. 

In view of these facts it may be inferred that dry-farming is anancient practice. It is improbable that intelligent men and womencould live in Mesopotamia, for example, for thousands of yearswithout discovering methods whereby the fertile soils could be madeto produce crops in a small degree at least without irrigation. True, the low development of implements for soil culture makes itfairly certain that dry-farming in those days was practiced onlywith infinite labor and patience; and that the great ancient nationsfound it much easier to construct great irrigation systems whichwould make crops certain with a minimum of soil tillage, than sothoroughly to till the soil with imperfect implements as to producecertain yields without irrigation. Thus is explained the fact thatthe historians of antiquity speak at length of the wonderfulirrigation systems, but refer to other forms of agriculture in amost casual manner. While the absence of agricultural machinerymakes it very doubtful whether dry-farming was practiced extensivelyin olden days, yet there can be little doubt of the high antiquityof the practice. 

Kearney quotes Tunis as an example of the possible extent ofdry-farming in early historical days. Tunis is under an averagerainfall of about nine inches, and there are no evidences ofirrigation having been practiced there, yet at El Djem are the ruinsof an amphitheater large enough to accommodate sixty thousandpersons, and in an area of one hundred square miles there werefifteen towns and forty-five villages. The country, therefore, musthave been densely populated. In the seventh century, according tothe Roman records, there were two million five hundred thousandacres of olive trees growing in Tunis and cultivated withoutirrigation. That these stupendous groves yielded well is indicatedby the statement that, under the Caesar's Tunis was taxed threehundred thousand gallons of olive oil annually. The production ofoil was so great that from one town it was piped to the nearestshipping port. This historical fact is borne out by the presentrevival of olive culture in Tunis, mentioned in Chapter XII. 

Moreover, many of the primitive peoples of to-day, the Chinese, Hindus, Mexicans, and the American Indians, are cultivating largeareas of land by dry-farm methods, often highly perfected, whichhave been developed generations ago, and have been handed down tothe present day. Martin relates that the Tarahumari Indians ofnorthern Chihuahua, who are among the most thriving aboriginaltribes of northern Mexico, till the soil by dry-farm methods andsucceed in raising annually large quantities of corn and othercrops. A crop failure among them is very uncommon. The earlyAmerican explorers, especially the Catholic fathers, foundoccasional tribes in various parts of America cultivating the soilsuccessfully without irrigation. All this points to the highantiquity of agriculture without irrigation in arid and semiaridcountries. 

Modern dry-farming in the United States

The honor of having originated modern dry-farming belongs to thepeople of Utah. On July 24th, 1847, Brigham Young with his band ofpioneers entered Great Salt Lake Valley, and on that day ground wasplowed, potatoes planted, and a tiny stream of water led from CityCreek to cover this first farm. The early endeavors of the Utahpioneers were devoted almost wholly to the construction ofirrigation systems. The parched desert ground appeared so differentfrom the moist soils of Illinois and Iowa, which the pioneers hadcultivated, as to make it seem impossible to produce crops withoutirrigation. Still, as time wore on, inquiring minds considered thepossibility of growing crops without irrigation; and occasionallywhen a farmer was deprived of his supply of irrigation water throughthe breaking of a canal or reservoir it was noticed by the communitythat in spite of the intense heat the plants grew and produced smallyields. 

Gradually the conviction grew upon the Utah pioneers that farmingwithout irrigation was not an impossibility; but the smallpopulation were kept so busy with their small irrigated farms thatno serious attempts at dry-farming were made during the first sevenor eight years. The publications of those days indicate thatdry-farming must have been practiced occasionally as early as 1854or 1855. 

About 1863 the first dry-farm experiment of any consequence occurredin Utah. A number of emigrants of Scandinavian descent had settledin what is now known as Bear River City, and had turned upon theirfarms the alkali water of Malad Creek, and naturally the cropsfailed. In desperation the starving settlers plowed up the sagebrushland, planted grain, and awaited results. To their surprise, fairyields of grain were obtained, and since that day dry-farming hasbeen an established practice in that portion of the Great Salt LakeValley. A year or two later, Christopher Layton, a pioneer whohelped to build both Utah and Arizona, plowed up land on the famousSand Ridge between Salt Lake City and Ogden and demonstrated thatdry-farm wheat could be grown successfully on the deep sandy soilwhich the pioneers had held to be worthless for agriculturalpurposes. Since that day the Sand Ridge has been famous as adry-farm district, and Major J. W. Powell, who saw the ripenedfields of grain in the hot dry sand, was moved upon to make specialmention of them in his volume on the "Arid Lands of Utah, " publishedin 1879. 

About this time, perhaps a year or two later, Joshua Salisbury andGeorge L. Farrell began dry-farm experiments in the famous CacheValley, one hundred miles north of Salt Lake City. After some yearsof experimentation, with numerous failures these and other pioneersestablished the practice of dry-farming in Cache Valley, which atpresent is one of the most famous dry-farm sections in the UnitedStates. In Tooele County, Just south of Salt Lake City, dry-farmingwas practiced in 1877--how much earlier is not known. In thenorthern Utah counties dry-farming assumed proportions ofconsequence only in the later '70's and early '80's. During the'80's it became a thoroughly established and extensive businesspractice in the northern part of the state. 

California, which was settled soon after Utah, began dry-farmexperiments a little later than Utah. The available informationindicates that the first farming without irrigation in Californiabegan in the districts of somewhat high precipitation. As thepopulation increased, the practice was pushed away from themountains towards the regions of more limited rainfall. According toHilgard, successful dry-farming on an extensive scale has beenpracticed in California since about 1868. Olin reports thatmoisture-saving methods were used on the Californian farms as earlyas 1861. Certainly, California was a close second in originatingdry-farming. 

The Columbia Basin was settled by Mareus Whitman near Walla Walla in1836, but farming did not gain much headway until the railroadpushed through the great Northwest about 1880. Those familiar withthe history of the state of Washington declare that dry-farming wasin successful operation in isolated districts in the late '70's. By1890 it was a well-established practice, but received a serioussetback by the financial panic of 1892-1893. Really successful andextensive dry-farming in the Columbia Basin began about 1897. Thepractice of summer fallow had begun a year or two before. It isinteresting to note that both in California and Washington there aredistricts in which dry-farming has been practiced successfully undera precipitation of about ten inches whereas in Utah the limit hasbeen more nearly twelve inches. 

In the Great Plains area the history of dry-farming Is hopelesslylost in the greater history of the development of the eastern andmore humid parts of that section of the country. The great influx ofsettlers on the western slope of the Great Plains area occurred inthe early '80's and overflowed into eastern Colorado and Wyoming afew years later. The settlers of this region brought with them themethods of humid agriculture and because of the relatively highprecipitation were not forced into the careful methods of moistureconservation that had been forced upon Utah, California, and theColumbia Basin. Consequently, more failures in dry-farming arereported from those early days in the Great Plains area than fromthe drier sections of the far West Dry-farming was practiced verysuccessfully in the Great Plains area during the later '80's. According to Payne, the crops of 1889 were very good; in 1890, lessso; in 1891, better; in 1892 such immense crops were raised that thesettlers spoke of the section as God's country; in 1893, there was apartial failure, and in 1894 the famous complete failure, which wasfollowed in 1895 by a partial failure. Since that time fair cropshave been produced annually. The dry years of 1893-1895 drove mostof the discouraged settlers back to humid sections and delayed, bymany years, the settlement and development of the western side ofthe Great Plains area. That these failures and discouragements weredue almost entirely to improper methods of soil culture is veryevident to the present day student of dry-farming. In fact, from thevery heart of the section which was abandoned in 1893-1895 comereliable records, dating back to 1886, which show successful cropproduction every year. The famous Indian Head experimental farm ofSaskatchewan, at the north end of the Great Plains area, has anunbroken record of good crop yields from 1888, and the early '90'swere quite as dry there as farther south. However, in spite of thevicissitudes of the section, dry-farming has taken a firm hold uponthe Great Plains area and is now a well-established practice. 

The curious thing about the development of dry-farming in Utah, California, Washington, and the Great Plains is that these foursections appear to have originated dry-farming independently of eachother. True, there was considerable communication from 1849 onwardbetween Utah and California, and there is a possibility that some ofthe many Utah settlers who located in California brought with themaccounts of the methods of dry-farming as practiced in Utah. This, however, cannot be authenticated. It is very unlikely that thefarmers of Washington learned dry-farming from their California orUtah neighbors, for until 1880 communication between Washington andthe colonies in California and Utah was very difficult, though, ofcourse, there was always the possibility of accounts of agriculturalmethods being carried from place to place by the moving emigrants. It is fairly certain that the Great Plains area did not draw uponthe far West for dry-farm methods. The climatic conditions areconsiderably different and the Great Plains people always consideredthemselves as living in a very humid country as compared with thestates of the far West. It may be concluded, therefore, that therewere four independent pioneers in dry-farming in United States. Moreover, hundreds, probably thousands, of individual farmers overthe semiarid region have practiced dry-farming thirty to fifty yearswith methods by themselves. 

Although these different dry-farm sections were developedindependently, yet the methods which they have finally adopted arepractically identical and include deep plowing, unless the subsoilis very lifeless; fall plowing; the planting of fall grain whereverfall plowing is possible; and clean summer fallowing. About 1895 theword began to pass from mouth to mouth that probably nearly all thelands in the great arid and semiarid sections of the United Statescould be made to produce profitable crops without irrigation. Atfirst it was merely a whisper; then it was talked aloud, and beforelong became the great topic of conversation among the thousands wholove the West and wish for its development. Soon it became aNational subject of discussion. Immediately after the close of thenineteenth century the new awakening had been accomplished anddry-farming was moving onward to conquer the waste places of theearth. 

H. W. Campbell

The history of the new awakening in dry-farming cannot well bewritten without a brief account of the work of H. W. Campbell who, in the public mind, has become intimately identified with thedry-farm movement. H. W. Campbell came from Vermont to northernSouth Dakota in 1879, where in 1882 he harvested a bannercrop, --twelve thousand bushels of wheat from three hundred acres. In1883, on the same farm he failed completely. This experience led himto a study of the conditions under which wheat and other crops maybe produced in the Great Plains area. A natural love forinvestigation and a dogged persistence have led him to give his lifeto a study of the agricultural problems of the Great Plains area. Headmits that his direct inspiration came from the work of JethroTull, who labored two hundred years ago, and his disciples. Heconceived early the idea that if the soil were packed near thebottom of the plow furrow, the moisture would be retained better andgreater crop certainty would result. For this purpose the firstsubsurface packer was invented in 1885. Later, about 1895, when hisideas had crystallized into theories, he appeared as the publisherof Campbell's "Soil Culture and Farm Journal. " One page of eachissue was devoted to a succinct statement of the "Campbell Method. "It was in 1898 that the doctrine of summer tillage was begun to beinvestigated by him. 

In view of the crop failures of the early '90's and the gradualdry-farm awakening of the later '90's, Campbell's work was receivedwith much interest. He soon became identified with the efforts ofthe railroads to maintain demonstration farms for the benefit ofintending settlers. While Campbell has long been in the service ofthe railroads of the semiarid region, yet it should be said in allfairness that the railroads and Mr. Campbell have had for theirprimary object the determination of methods whereby the farmerscould be made sure of successful crops. 

Mr. Campbell's doctrines of soil culture, based on his accumulatedexperience, are presented in Campbell's "Soil Culture Manual, " thefirst edition of which appeared about 1904 and the latest edition, considerably extended, was published in 1907. The 1907 manual is thelatest official word by Mr. Campbell on the principles and methodsof the "Campbell system. " The essential features of the system maybe summarized as follows: The storage of water in the soil isimperative for the production of crops in dry years. This may beaccomplished by proper tillage. Disk the land immediately afterharvest; follow as soon as possible with the plow; follow the plowwith the subsurface packer; and follow the packer with the smoothingharrow. Disk the land again as early as possible in the spring andstir the soil deeply and carefully after every rain. Sow thinly inthe fall with a drill. If the grain is too thick in the spring, harrow it out. To make sure of a crop, the land should be "summertilled, " which means that clean summer fallow should be practicedevery other year, or as often as may be necessary. 

These methods, with the exception of the subsurface packing, aresound and in harmony with the experience of the great dry-farmsections and with the principles that are being developed byscientific investigation. The "Campbell system" as it stands to-dayis not the system first advocated by him. For instance, in thebeginning of his work he advocated sowing grain in April and in rowsso far apart that spring tooth harrows could be used for cultivatingbetween the rows. This method, though successful in conservingmoisture, is too expensive and is therefore superseded by thepresent methods. Moreover, his farm paper of 1896, containing a fullstatement of the "Campbell method, " makes absolutely no mention of"summer tillage, " which is now the very keystone of the system. These and other facts make it evident that Mr. Campbell has veryproperly modified his methods to harmonize with the best experience, but also invalidate the claim that he is the author of the dry-farmsystem. A weakness of the "Campbell system" is the continualinsistence upon the use of the subsurface packer. As has alreadybeen shown, subsurface packing is of questionable value forsuccessful crop production, and if valuable, the results may be muchmore easily and successfully obtained by the use of the disk andharrow and other similar implements now on the market. Perhaps theone great weakness in the work of Campbell is that he has notexplained the principles underlying his practices. His publicationsonly hint at the reasons. H. W. Campbell, however, has done much topopularize the subject of dry-farming and to prepare the way forothers. His persistence in his work of gathering facts, writing, andspeaking has done much to awaken interest in dry-farming. He hasbeen as "a voice in the wilderness" who has done much to makepossible the later and more systematic study of dry-farming. Highhonor should be shown him for his faith in the semiarid region, forhis keen observation, and his persistence in the face ofdifficulties. He is justly entitled to be ranked as one of the greatworkers in behalf of the reclamation, without irrigation, of therainless sections of the world. 

The experiment stations

The brave pioneers who fought the relentless dryness of the GreatAmerican Desert from the memorable entrance of the Mormon pioneersinto the valley of the Great Salt Lake in 1847 were not the onlyones engaged in preparing the way for the present day of greatagricultural endeavor. Other, though perhaps more indirect, forceswere also at work for the future development of the semiaridsection. The Morrill Bill of 1862, making it possible foragricultural colleges to be created in the various states andterritories, indicated the beginning of a public feeling that modernmethods should be applied to the work of the farm. The passage in1887 of the Hatch Act, creating agricultural experiment stations inall of the states and territories, finally initiated a newagricultural era in the United States. With the passage of thisbill, stations for the application of modern science to cropproduction were for the first time authorized in the regions oflimited rainfall, with the exception of the station connected withthe University of California, where Hilgard from 1872 had beenlaboring in the face of great difficulties upon the agriculturalproblems of the state of California. During the first few years oftheir existence, the stations were busy finding men and problems. The problems nearest at hand were those that had been attacked bythe older stations founded under an abundant rainfall and whichcould not be of vital interest to arid countries. The westernstations soon began to attack their more immediate problems, and itwas not long before the question of producing crops withoutirrigation on the great unirrigated stretches of the West wasdiscussed among the station staffs and plans were projected for astudy of the methods of conquering the desert. 

The Colorado Station was the first to declare its good intentions inthe matter of dry-farming, by inaugurating definite experiments. Bythe action of the State Legislature of 1893, during the time of thegreat drouth, a substation was established at Cheyenne Wells, nearthe west border of the state and within the foothills of the GreatPlains area. From the summer of 1894 until 1900 experiments wereconducted on this farm. The experiments were not based upon anydefinite theory of reclamation, and consequently the work consistedlargely of the comparison of varieties, when soil treatment was theall-important problem to be investigated. True in 1898, a trial ofthe "Campbell method" was undertaken. By the time this Station hadpassed its pioneer period and was ready to enter upon moresystematic investigation, it was closed. Bulletin 59 of the ColoradoStation, published in 1900 by J. E. Payne, gives a summary ofobservations made on the Cheyenne Wells substation during sevenyears. This bulletin is the first to deal primarily with theexperimental work relating to dry-farming in the Great Plains area. It does not propose or outline any system of reclamation. Severallater publications of the Colorado Station deal with the problemspeculiar to the Great Plains. 

At the Utah Station the possible conquest of the sagebrush desertsof the Great Basin without irrigation was a topic of commonconversation during the years 1894 and 1895. In 1896 plans werepresented for experiments on the principles of dry-farming. Fouryears later these plans were carried into effect. In the summer of1901, the author and L. A. Merrill investigated carefully thepractices of the dry-farms of the state. On the basis of theseobservations and by the use of the established principles of therelation of water to soils and plants, a theory of dry-farming wasworked out which was published in Bulletin 75 of the Utah Station inJanuary, 1902. This is probably the first systematic presentation ofthe principles of dry-farming. A year later the Legislature of thestate of Utah made provision for the establishment and maintenanceof six experimental dry-farms to investigate in different parts ofthe state the possibility of dry-farming and the principlesunderlying the art. These stations, which are still maintained, havedone much to stimulate the growth of dry-farming in Utah. The creditof first undertaking and maintaining systematic experimental work inbehalf of dry-farming should be assigned to the state of Utah. Sincedry-farm experiments began in Utah in 1901, the subject has been aleading one in the Station and the College. A large number of mentrained at the Utah Station and College have gone out asinvestigators of dry-farming under state and Federal direction. 

The other experiment stations in the arid and semi-arid region werenot slow to take up the work for their respective states. Fortierand Linfield, who had spent a number of years in Utah and had becomesomewhat familiar with the dry-farm practices of that state, initiated dry-farm investigations in Montana, which have beenprosecuted with great vigor since that time. Vernon, under thedirection of Foster, who had spent four years in Utah as Director ofthe Utah Station, initiated the work in New Mexico. In Wyoming theexperimental study of dry-farm lands began by the private enterpriseof H. B. Henderson and his associates. Later V. T. Cooke was placedin charge of the work under state auspices, and the demonstration ofthe feasibility of dry-farming in Wyoming has been going on sinceabout 1907. Idaho has also recently undertaken dry-farminvestigations. Nevada, once looked upon as the only state in theUnion incapable of producing crops without irrigation, isdemonstrating by means of state appropriations that large areasthere are suitable for dry-farming. In Arizona, small tracts in thissun-baked state are shown to be suitable for dry-farm lands. TheWashington Station is investigating the problems of dry-farmingpeculiar to the Columbia Basin, and the staff of the Oregon Stationis carrying on similar work. In Nebraska, some very importantexperiments dry-farming are being conducted. In North Dakota therewere in 1910 twenty-one dry-farm demonstration farms. In SouthDakota, Kansas, and Texas, provisions are similarly made fordry-farm investigations. In fact, up and down the Great Plains areathere are stations maintained by the state or Federal government forthe purpose of determining the methods under which crops can beproduced without irrigation. 

At the head of the Great Plains area at Saskatchewan one of theoldest dry-farm stations in America is located (since 1888). InRussia several stations are devoted very largely to the problems ofdry land agriculture. To be especially mentioned for the excellenceof the work done are the stations at Odessa, Cherson, and Poltava. This last-named Station has been established since 1886. 

In connection with the work done by the experiment stations shouldbe mentioned the assistance given by the railroads. Many of therailroads owning land along their respective lines are greatlybenefited in the selling of these lands by a knowledge of themethods whereby the lands may be made productive. However, therailroads depend chiefly for their success upon the increasedprosperity of the population along their lines and for the purposeof assisting the settlers in the arid West considerable sums havebeen expended by the railroads in cooperation with the stations forthe gathering of information of value in the reclamation of aridlands without irrigation. 

It is through the efforts of the experiment stations that theknowledge of the day has been reduced to a science of dry-farming. Every student of the subject admits that much is yet to be learnedbefore the last word has been said concerning the methods ofdry-farming in reclaiming the waste places of the earth. The futureof dry-farming rests almost wholly upon the energy and intelligencewith which the experiment stations in this and other countries ofthe world shall attack the special problems connected with thisbranch of agriculture. 

The United States Department of Agriculture

The Commissioner of Agriculture of the United States was given asecretaryship in the President's Cabinet in 1889. With this addeddignity, new life was given to the department. Under the directionof J. Sterling Morton preliminary work of great importance was done. Upon the appointment of James Wilson as Secretary of Agriculture, the department fairly leaped into a fullness of organization for theinvestigation of the agricultural problems of the country. From thebeginning of its new growth the United States Department ofAgriculture has given some thought to the special problems of thesemiarid region, especially that part within the Great Plains. Little consideration was at first given to the far West. The firstmethod adopted to assist the farmers of the plains was to findplants with drouth resistant properties. For that purpose explorerswere sent over the earth, who returned with great numbers of newplants or varieties of old plants, some of which, such as the durumwheats, have shown themselves of great value in Americanagriculture. The Bureaus of Plant Industry, Soils, Weather, andChemistry have all from the first given considerable attention tothe problems of the arid region. The Weather Bureau, longestablished and with perfected methods, has been invaluable inguiding investigators into regions where experiments could beundertaken with some hope of success. The Department of Agriculturewas somewhat slow, however, in recognizing dry-farming as a systemof agriculture requiring special investigation. The finalrecognition of the subject came with the appointment, in 1905, ofChilcott as expert in charge of dry-land investigations. At thepresent time an office of dry-land investigations has beenestablished under the Bureau of Plant Industry, which cooperateswith a number of other divisions of the Bureau in the investigationof the conditions and methods of dry-farming. A large number ofstations are maintained by the Department over the arid and semiaridarea for the purpose of studying special problems, many of which aremaintained in connection with the state experiment stations. Nearlyall the departmental experts engaged in dry-farm investigation havebeen drawn from the service of the state stations and in thesestations had received their special training for their work. TheUnited States Department of Agriculture has chosen to adopt a strongconservatism in the matter of dry-farming. It may be wise for theDepartment, as the official head of the agricultural interests ofthe country, to use extreme care in advocating the settlement of aregion in which, in the past, farmers had failed to make a living, yet this conservatism has tended to hinder the advancement ofdry-farming and has placed the departmental investigations ofdry-farming in point of time behind the pioneer investigations ofthe subject. 

The Dry-farming Congress

As the great dry-farm wave swept over the country, the need was felton the part of experts and laymen of some means whereby dry-farmideas from all parts of the country could be exchanged. Privateindividuals by the thousands and numerous state and governmentalstations were working separately and seldom had a chance ofcomparing notes and discussing problems. A need was felt for somecentral dry-farm organization. An attempt to fill this need was madeby the people of Denver, Colorado, when Governor Jesse F. McDonaldof Colorado issued a call for the first Dry-farming Congress to beheld in Denver, January 24, 25, and 26, 1907. These dates were thoseof the annual stock show which had become a permanent institution ofDenver and, in fact, some of those who were instrumental in thecalling of the Dry-farming Congress thought that it was a goodscheme to bring more people to the stock show. To the surprise ofmany the Dry-farming Congress became the leading feature of theweek. Representatives were present from practically all the statesinterested in dry-farming and from some of the humid states. Utah, the pioneer dry-farm state, was represented by a delegation secondin size only to that of Colorado, where the Congress was held. Thecall for this Congress was inspired, in part at least, by realestate men, who saw in the dry-farm movement an opportunity torelieve themselves of large areas of cheap land at fairly goodprices. The Congress proved, however, to be a businesslike meetingwhich took hold of the questions in earnest, and from the very firstmade it clear that the real estate agent was not a welcome memberunless he came with perfectly honest methods. 

The second Dry-farming Congress was held January 22 to 25, 1908, inSalt Lake City, Utah, under the presidency of Fisher Harris. It waseven better attended than the first. The proceedings show that itwas a Congress at which the dry-farm experts of the country statedtheir findings. A large exhibit of dry-farm products was held inconnection with this Congress, where ocular demonstrations of thepossibility of dry-farming were given any doubting Thomas. 

The third Dry-farming Congress was held February 23 to 25, 1909, atCheyenne, Wyoming, under the presidency of Governor W. W. Brooks ofWyoming. An unusually severe snowstorm preceded the Congress, whichprevented many from attending, yet the number present exceeded thatat any of the preceding Congresses. This Congress was made notableby the number of foreign delegates who had been sent by theirrespective countries to investigate the methods pursued in Americafor the reclamation of the arid districts. Among these delegateswere representatives from Canada, Australia, The Transvaal, Brazil, and Russia. 

The fourth Congress was held October 26 to 28, 1909, in Billings, Montana, under the presidency of Governor Edwin L. Morris ofMontana. The uncertain weather of the winter months had led theprevious Congress to adopt a time in the autumn as the date of theannual meeting. This Congress became a session at which many of theprinciples discussed during the three preceding Congresses werecrystallized into definite statements and agreed upon by workersfrom various parts of the country. A number of foreignrepresentatives were present again. The problems of the Northwestand Canada were given special attention. The attendance was largerthan at any of the preceding Congresses. 

The fifth Congress will be held under the presidency of Hon. F. W. Mondell of Wyoming at Spokane, Washington, during October, 1910. Itpromises to exceed any preceding Congress in attendance andinterest. 

The Dry-farming Congress has made itself one of the most importantfactors in the development of methods for the reclamation of thedesert. Its published reports are the most valuable publicationsdealing with dry-land agriculture. Only simple justice is done whenit is stated that the success of the Dry-farming Congress is due ina large measure to the untiring and intelligent efforts of John T. Burns, who is the permanent secretary of the Congress, and who was amember of the first executive committee. 

Nearly all the arid and semiarid states have organized statedry-farming congresses. The first of these was the Utah Dry-farmingCongress, organized about two months after the first Congress heldin Denver. The president is L. A. Merrill, one of the pioneerdry-farm investigators of the Rockies. 

Jethro Tull (see frontispiece)

A sketch of the history of dry-farming would be incomplete without amention of the life and work of Jethro Tull. The agriculturaldoctrines of this man, interpreted in the light of modern science, are those which underlie modern dry-farming. Jethro Tull was born inBerkshire, England, 1674, and died in 1741. He was a lawyer byprofession, but his health was so poor that he could not practicehis profession and therefore spent most of his life in the seclusionof a quiet farm. His life work was done in the face of greatphysical sufferings. In spite of physical infirmities, he produced asystem of agriculture which, viewed in the light of our modernknowledge, is little short of marvelous. The chief inspiration ofhis system came from a visit paid to south of France, where heobserved "near Frontignan and Setts, Languedoc" that the vineyardswere carefully plowed and tilled in order to produce the largestcrops of the best grapes. Upon the basis of this observation heinstituted experiments upon his own farm and finally developed hissystem, which may be summarized as follows: The amount of seed to beused should be proportional to the condition of the land, especiallyto the moisture that is in it. To make the germination certain, theseed should be sown by drill methods. Tull, as has already beenobserved, was the inventor of the seed drill which is now a featureof all modern agriculture. Plowing should be done deeply andfrequently; two plowings for one crop would do no injury andfrequently would result in an increased yield. Finally, as the mostimportant principle of the system, the soil should be cultivatedcontinually, the argument being that by continuous cultivation thefertility of the soil would be increased, the water would beconserved, and as the soil became more fertile less water would beused. To accomplish such cultivation, all crops should be placed inrows rather far apart, so far indeed that a horse carrying acultivator could walk between them. The horse-hoeing idea of thesystem became fundamental and gave the name to his famous book, "TheHorse Hoeing Husbandry, " by Jethro Tull, published in parts from1731 to 1741. Tull held that the soil between the rows wasessentially being fallowed and that the next year the seed could beplanted between the rows of the preceding year and in that way thefertility could be maintained almost indefinitely. If this methodwere not followed, half of the soil could lie fallow every otheryear and be subjected to continuous cultivation. Weeds consume waterand fertility and, therefore, fallowing and all the culture must beperfectly clean. To maintain fertility a rotation of crops should bepracticed. Wheat should be the main grain crop; turnips the rootcrop; and alfalfa a very desirable crop. 

It may be observed that these teachings are sound and in harmonywith the best knowledge of to-day and that they are the verypractices which are now being advocated in all dry-farm sections. This is doubly curious because Tull lived in a humid country. However, it may be mentioned that his farm consisted of a very poorchalk soil, so that the conditions under which he labored were morenearly those of an arid country than could ordinarily be found in acountry of abundant rainfall. While the practices of Jethro Tullwere in themselves very good and in general can be adopted to-day, yet his interpretation of the principles involved was wrong. In viewof the limited knowledge of his day, this was only to be expected. For instance, he believed so thoroughly in the value of cultivationof the soil, that he thought it would take the place of all othermethods of maintaining soil-fertility. In fact, he declareddistinctly that "tillage is manure, " which we are very certain atthis time is fallacious. Jethro Tull is one of the greatinvestigators of the world. In recognition of the fact that, thoughliving two hundred years ago in a humid country, he was able todevelop the fundamental practices of soil culture now used indry-farming, the honor has been done his memory of placing hisportrait as the frontispiece of this volume. 

CHAPTER XX

DRY-FARMING IN A NUTSHELL

Locate the dry-farm in a section with an annual precipitation ofmore than ten inches and, if possible, with small wind movement. Oneman with four horses and plenty of machinery cannot handle more thanfrom 160 to 200 acres. Farm fewer acres and farm them better. 

Select a clay loam soil. Other soils may be equally productive, butare cultivated properly with somewhat more difficulty. 

Make sure, with the help of the soil auger, that the soil is ofuniform structure to a depth of at least eight feet. If streaks ofloose gravel or layers of hardpan are near the surface, water may belost to the plant roots. 

After the land has been cleared and broken let it lie fallow withclean cultivation, for one year. The increase in the first and latercrops will pay for the waiting. 

Always plow the land early in the fall, unless abundant experienceshows that fall plowing is an unwise practice in the locality. Always plow deeply unless the subsoil is infertile, in which caseplow a little deeper each year until eight or ten inches are reachedPlow at least once for each crop. Spring plowing; if practiced, should be done as early as possible in the season. 

Follow the plow, whether in the fall or spring, with the disk andthat with the smoothing harrow, if crops are to be sown soonafterward. If the land plowed in the fall is to lie fallow for thewinter, leave it in the rough condition, except in localities wherethere is little or no snow and the winter temperature is high. 

Always disk the land in early spring, to prevent evaporation. Followthe disk with the harrow. Harrow, or in some other way stir thesurface of the soil after every rain. If crops are on the land, harrow as long as the plants will stand it. If hoed crops, like cornor potatoes, are grown, use the cultivator throughout the season. Adeep mulch or dry soil should cover the land as far as possiblethroughout the summer. Immediately after harvest disk the soilthoroughly. 

Destroy weeds as soon as they show themselves. A weedy dry-farm isdoomed to failure. 

Give the land an occasional rest, that is, a clean summer fallow. Under a rainfall of less than fifteen inches, the land should besummer fallowed every other year; under an annual rainfall offifteen to twenty inches, the summer fallow should occur every thirdor fourth year. Where the rainfall comes chiefly in the summer, thesummer fallow is less important in ordinary years than where thesummers are dry and the winters wet. Only an absolutely clean fallowshould be permitted. 

The fertility of dry-farm soils must be maintained. Return themanure; plow under green leguminous crops occasionally and practicerotation. On fertile soils plants mature with the least water. 

Sow only by the drill method. Wherever possible use fall varietiesof crops. Plant deeply--three or four inches for grain. Plant earlyin the fall, especially if the land has been summer fallowed. Useonly about one half as much seed as is recommended forhumid-farming. 

All the ordinary crops may be grown by dry-farming. Secure seed thathas been raised on dry-farms. Look out for new varieties, especiallyadapted for dry-farming, that may be brought in. Wheat is king indry-farming; corn a close second. Turkey wheat promises the best. 

Stock the dry-farm with the best modern machinery. Dry-farming ispossible only because of the modern plow, the disk, the drillseeder, the harvester, the header, and the thresher. 

Make a home on the dry-farm. Store the flood waters in a reservoir;or pump the underground waters, for irrigating the family garden. Set out trees, plant flowers, and keep some live stock. 

Learn to understand the reasons back of the principles ofdry-farming, apply the knowledge vigorously, and the crop cannotfail. 

Always farm as if a year of drouth were coming. 

Man, by his intelligence, compels the laws of nature to do hisbidding, and thus he achieves joy. 

"And God blessed them--and God said unto them, Be fruitful andmultiply and replenish the earth, and subdue it. "

CHAPTER XIX

THE YEAR OF DROUTH

The Shadow of the Year of Drouth still obscures the hope of many adry-farmer. From the magazine page and the public platform theprophet of evil, thinking himself a friend of humanity, solemnlywarns against the arid region and dry-farming, for the year ofdrouth, he says, is sure to come again and then will be repeated thedisasters of 1893-1895. Beware of the year of drouth. Evensuccessful dry-farmers who have obtained good crops every year for ageneration or more are half led to expect a dry year or one so drythat crops will fail in spite of all human effort. The question iscontinually asked, "Can crop yields reasonably be expected everyyear, through a succession of dry years, under semiarid conditions, if the best methods of dry-farming be practiced?" In answering thisquestion, it may be said at the very beginning, that when the yearof drouth is mentioned in connection with dry-farming, sad referenceis always made to the experience on the Great Plains in the earlyyears of the '90's. Now the fact of the matter is, that while theyears of 1893, 1894, and 1895 were dry years, the only completefailure came in 1894. In spite of the improper methods practiced bythe settlers, the willing soil failed to yield a crop only one year. Moreover, it should not be forgotten that hundreds of farmers in thedriest section during this dry period, who instinctively orotherwise farmed more nearly right, obtained good crops even in1894. The simple practice of summer fallowing, had it been practicedthe year before, would have insured satisfactory crops in the driestyear. Further, the settlers who did not take to their heels upon thearrival of the dry year are still living in large numbers on theirhomesteads and in numerous instances have accumulated comfortablefortunes from the land which has been held up so long as a warningagainst settlement beyond a humid climate. The failure of 1894 wasdue as much to a lack of proper agricultural information andpractice as to the occurrence of a dry year. 

Next, the statement is carelessly made that the recent success indry-farming is due to the fact that we are now living in a cycle ofwet years, but that as soon as the cycle of dry years strikes thecountry dry-farming will vanish as a dismal failure. Then, again, the theory is proposed that the climate is permanently changingtoward wetness or dryness and the past has no meaning in reading theriddle of the future. It is doubtless true that no man may safelypredict the weather for future generations; yet, so far as humanknowledge goes, there is no perceptible average change in theclimate from period to period within historical time; neither arethere protracted dry periods followed by protracted wet periods. Thefact is, dry and wet years alternate. A succession of somewhat wetyears may alternate with a succession of somewhat dry years, but theaverage precipitation from decade to decade is very nearly the same. True, there will always be a dry year, that is, the driest year of aseries of years, and this is the supposedly fearful and fateful yearof drouth. The business of the dry-farmer is always to farm so as tobe prepared for this driest year whenever it comes. If this be done, the farmer will always have a crop: in the wet years his crop willbe large; in the driest year it will be sufficient to sustain him. 

So persistent is the half-expressed fear that this driest year makesit impossible to rely upon dry-farming as a permanent system ofagriculture that a search has been made for reliable long records ofthe production of crops in arid and semiarid regions. Publicstatements have been made by many perfectly reliable men to theeffect that crops have been produced in diverse sections over longperiods of years, some as long as thirty-five or forty year's, without one failure having occurred. Most of these statements, however, have been general in their nature and not accompanied bythe exact yields from year to year. Only three satisfactory recordshave been found in a somewhat careful search. Others no doubt exist. 

The first record was made by Senator J. G. M. Barnes of Kaysville, Utah. Kaysville is located in the Great Salt Lake Valley, aboutfifteen miles north of Salt Lake City. The climate is semiarid; theprecipitation comes mainly in the winter and early spring; thesummers are dry, and the evaporation is large. Senator Barnespurchased ninety acres of land in the spring of 1887 and had itfarmed under his own supervision until 1906. He is engaged incommercial enterprises and did not, himself, do any of the work onthe farm, but employed men to do the necessary labor. However, hekept a close supervision of the farm and decided upon the practiceswhich should be followed. From seventy-eight to eighty-nine acreswere harvested for each crop, with the exception of 1902, when allbut about twenty acres was fired by sparks from the passing railroadtrain. The plowing, harrowing, and weeding were done very carefully. The complete record of the Barnes dry-farm from 1887 to 1905 isshown in the table on the following page. 

Record of the Barnes Dry-farm, Salt Lake Valley, Utah (90 acres)

Year Annual Yield When When Rainfall per Acre Plowed Sown (Inches) (Bu. )1887 11. 66 --- May Sept. 1888 13. 62 Failure May Sept. 1889 18. 46 22. 5 --- Volunteer+1890 10. 38 15. 5 --- ---1891 15. 92 Fallow May Fall1892 14. 08 19. 3 --- ---1893 17. 35 Fallow May Fall1894 15. 27 26. 0 --- ---1895 11. 95 Fallow May Aug. 1896 18. 42 22. 0 --- ---1897 16. 74 Fallow Spring Fall1898 16. 09 26. 0 --- ---1899 17. 57 Fallow May Fall1900 11. 53 23. 5 --- ---1901 16. 08 Fallow Spring Fall1902 11. 41 28. 9 Sept. Fall1903 14. 62 12. 5 --- ---1904 16. 31 Fallow Spring Fall1905 14. 23 25. 8 --- ---

+About four acres were sown on stubble. 

The first plowing was given the farm in May of 1887, and, with theexception of 1902, the land was invariably plowed in the spring. With fall plowing the yields would undoubtedly have been better. Thefirst sowing was made in the fall of 1887, and fall grain was grownduring the whole period of observation. The seed sown in the fall of1887 came up well, but was winter-killed. This is ascribed bySenator Barnes to the very dry winter, though it is probable thatthe soil was not sufficiently well stored with moisture to carry thecrop through. The farm was plowed again in the spring of 1888, andanother crop sown in September of the same year. In the summer of1889, 22-1/2 bushels of wheat were harvested to the acre. Encouragedby this good crop Mr. Barnes allowed a volunteer crop to grow thatfall and the next summer harvested as a result 15-1/2 bushels ofwheat to the acre. The table shows that only one crop smaller thanthis was harvested during the whole period of nineteen years, namely, in 1903, when the same thing was done, and one crop was madeto follow another without an intervening fallow period. Thisobservation is an evidence in favor of clean summer fallowing. Thelargest crop obtained, 28. 9 bushels per acre in 1902, was gatheredin a year when the next to the lowest rainfall of the whole periodoccurred, namely, 11. 41 inches. 

The precipitation varied during the nineteen years from 10. 33 inchesto 18. 46 inches. The variation in yield per acre was considerablyless than this, not counting the two crops that were grownimmediately after another crop. All in all, the unique record of theBarnes dry-farm shows that through a period of nineteen years, including dry and comparatively wet years, there was absolutely nosign of failure, except in the first year, when probably the soilhad not been put in proper condition to support crops. In passing itmaybe mentioned that, according to the records furnished by SenatorBarnes, the total cost of operating the farm during the nineteenyears was $4887. 69; the total income was $10, 144. 83. The difference, $5257. 14, is a very fair profit on the investment of $1800--theoriginal cost of the farm. 

The Indian Head farm

An equally instructive record is furnished by the experimental farmlocated at Indian Head in Saskatchewan, Canada, in the northern partof the Great Plains area. According to Alway, the country is inappearance very much like western Nebraska and Kansas; the climateis distinctly arid, and the precipitation comes mainly in the springand summer. It is the only experimental dry-farm in the Great Plainsarea with records that go back before the dry years of the early'90's. In 1882 the soil of this farm was broken, and it was farmedcontinuously until 1888, when it was made an experimental farm undergovernment supervision. The following table shows the yieldsobtained from the year 1891, when the precipitation records werefirst kept, to 1909:--

RECORD OF INDIAN HEAD EXPERIMENTAL FARM AND MOTHERWELL'S FARM, SASKATCHEWAN, CANADA

Year Annual Bushels of Wheat Bushels of Wheat Bushels of Wheat Rainfall per Acre per Acre per Acre (Inches)+ Experimental Experimental Motherwell's Farm Farm--Fallow Farm--Stubble1891 14. 03 35 32 301892 6. 92 28 21 281893 10. 11 35 22 341894 3. 90 17 9 241895 12. 28 41 22 261896 10. 59 39 29 311897 14. 62 33 26 351898 18. 03 32 --- 271899 9. 44 33 --- 331900 11. 74 17 5 251901 20. 22 49 38 511902 10. 73 38 22 281903 15. 55 35 15 311904 11. 96 40 29 351905 19. 17 42 18 361906 13. 21 26 13 381907 15. 03 18 18 151908 13. 17 29 14 161909 13. 96 28 15 23

+Snowfall not included. This has varied from 2. 3 to 1. 3 inches of water. 

The annual rainfall shown in the second column does not include thewater which fell in the form of snow. According to the records athand, the annual snow fall varied from 2. 3 to 1. 3 inches of water, which should be added to the rainfall given in the table. Even withthis addition the rainfall shows the district to be of a distinctlysemiarid character. It will be observed that the precipitationvaried from 3. 9 to 20. 22 inches, and that during the early '90'sseveral rather dry years occurred. In spite of this large variationgood crops have been obtained during the whole period of nineteenyears. Not one failure is recorded. The lowest yield of 17 bushelsper acre came during the very dry year of 1894 and during thesomewhat dry year of 1900. Some of the largest yields were obtainedin seasons when the rainfall was only near the average. As a recordshowing that the year of drouth need not be feared when dry-farmingis done right, this table is of very high interest. It may be noted, incidentally, that throughout the whole period wheat following afallow always yielded higher than wheat following the stubble. Forthe nineteen years, the difference was as 32. 4 bushels is to 20. 5bushels. 

The Mother well farm

In the last column of the table are shown the annual yields of wheatobtained on the farm of Commissioner Motherwell of the province ofSaskatchewan. This private farm is located some twenty-five milesaway from Indian Head, and the rainfall records of the experimentalfarm are, therefore, only approximately accurate for the Motherwellfarm. The results on this farm may well be compared to the Barnesresults of Utah, since they were obtained on a private farm. Duringthe period of nineteen years good crops were invariably obtained;even during the very dry year of 1894, a yield of twenty-fourbushels of wheat to the acre was obtained. Curiously enough, thelowest yields of fifteen and sixteen bushels to the acre wereobtained in 1907 and 1908 when the precipitation was fairly good, and must be ascribed to some other factor than that ofprecipitation. The record of this farm shows conclusively that withproper farming there is no need to fear the year of drouth. 

The Utah drouth of 1910

During the year of 1910 only 2. 7 inches of rain fell in Salt LakeCity from March 1 to the July harvest, and all of this in March, asagainst 7. 18 inches during the same period the preceding year. Inother parts of the state much less rain fell; in fact, in thesouthern part of the state the last rain fell during the last weekof December, 1909. The drouth remained unbroken until long after thewheat harvests. Great fear was expressed that the dry-farms couldnot survive so protracted a period of drouth. Agents, sent out overthe various dry-farm districts, reported late in June that whereverclean summer fallowing had been practiced the crops were inexcellent condition; but that wherever careless methods had beenpracticed, the crops were poor or killed. The reports of the harvestin July of 1910 showed that fully 85 per cent of an average crop wasobtained in spite of the protracted drouth wherever the soil cameinto the spring well stored with moisture, and in many instancesfull crops were obtained. 

Over the whole of the dry-farm territory of the United Statessimilar conditions of drouth occurred. After the harvest, however, every state reported that the crops were well up to the averagewherever correct methods of culture had been employed. 

These well-authenticated records from true semi-arid districts, covering the two chief types of winter and summer precipitation, prove that the year of drouth, or the driest year in a twenty-yearperiod, does not disturb agricultural conditions seriously inlocalities where the average annual precipitation is not too low, and where proper cultural methods arc followed. That dry-farming isa system of agricultural practice which requires the application ofhigh skill and intelligence is admitted; that it is precarious isdenied. The year of drouth is ordinarily the year in which the manfailed to do properly his share of the work. 

CHAPTER XVIII

THE PRESENT STATUS OF DRY-FARMING

It is difficult to obtain a correct view of the present status ofdry-farming, first, because dry-farm surveys are only beginning tobe made and, secondly, because the area under dry-farm cultivationis increasing daily by leaps and bounds. All arid and semiarid partsof the world are reaching out after methods of soil culture wherebyprofitable crops may be produced without irrigation, and thepractice of dry-farming, according to modern methods, is nowfollowed in many diverse countries. The United States undoubtedlyleads at present in the area actually under dry-farming, but, inview of the immense dry-farm districts in other parts of the world, it is doubtful if the United States will always maintain itssupremacy in dry-farm acreage. The leadership in the development ofa science of dry-farming will probably remain with the United Statesfor years, since the numerous experiment stations established forthe study of the problems of farming without irrigation have theirwork well under way, while, with the exception of one or twostations in Russia and Canada, no other countries have experimentstations for the study of dry-farming in full operation. The reportsof the Dry-farming Congress furnish practically the only generalinformation as to the status of dry-farming in the states andterritories of the United States and in the countries of the world. 

California

In the state of California dry-farming has been firmly establishedfor more than a generation. The chief crop of the Californiadry-farms is wheat, though the other grains, root crops, andvegetables are also grown without irrigation under a comparativelysmall rainfall. The chief dry-farm areas are found in the Sacramentoand the San Joaquin valleys. In the Sacramento Valley theprecipitation is fairly large, but in the San Joaquin Valley it isvery small. Some of the most successful dry-farms of California haveproduced well for a long succession of years under a rainfall of teninches and less. California offers a splendid example of the greatdanger that besets all dry-farm sections. For a generation wheat hasbeen produced on the fertile Californian soils without manuring ofany kind. As a consequence, the fertility of the soils has been sofar depleted that at present it is difficult to obtain paying cropswithout irrigation on soils that formerly yielded bountifully. Theliving problem of the dry-farms in California is the restoration ofthe fertility which has been removed from the soils by unwisecropping. All other dry-farm districts should take to heart thislesson, for, though crops may be produced on fertile soils for one, two, or even three generations without manuring, yet the time willcome when plant-food must be added to the soil in return for thatwhich has been removed by the crops. Meanwhile, California offers, also, an excellent example of the possibility of successfuldry-farming through long periods and under varying climaticconditions. In the Golden State dry-farming is a fully establishedpractice; it has long since passed the experimental stage. 

Columbia River Basin

The Columbia River Basin includes the state of Washington, most ofOregon, the northern and central part of Idaho, western Montana, andextends into British Columbia. It includes the section often calledthe Inland Empire, which alone covers some one hundred and fiftythousand square miles. The chief dry-farm crop of this region iswheat; in fact, western Washington or the "Palouse country" isfamous for its wheat-producing powers. The other grains, potatoes, roots, and vegetables are also grown without irrigation. In theparts of this dry-farm district where the rainfall is the highest, fruits of many kinds and of a high quality are grown withoutirrigation. It is estimated that at least two million acres arebeing dry-farmed in this district. Dry-farming is fully establishedin the Columbia River Basin. One farmer is reported to have raisedin one year on his own farm two hundred and fifty thousand bushelsof wheat. In one section of the district where the rainfall for thelast few years has been only about ten or eleven inches, wheat hasbeen produced successfully. This corroborates the experience ofCalifornia, that wheat may really be grown in localities where theannual rainfall is not above ten inches. The most modern methods ofdry-farming are followed by the farmers of the Columbia River Basin, but little attention has been given to soil-fertility, since soilsthat have been farmed for a generation still appear to retain theirhigh productive powers. Undoubtedly, however, in this district, asin California, the question of soil-fertility will be an importantone in the near future. This is one of the great dry-farm districtsof the world. 

The Great Basin

The Great Basin includes Nevada, the western half of Utah, a smallpart of southern Oregon and Idaho, and also a part of SouthernCalifornia. It is a great interior basin with all its riversdraining into salt lakes or dry sinks. In recent geological timesthe Great Basin was filled with water, forming the great LakeBonneville which drained into the Columbia River. In fact, the GreatBasin is made up of a series of great valleys, with very levelfloors, representing the old lake bottom. On the bench lands areseen, in many places, the effects of the wave action of the ancientlake. The chief dry-farm crop of this district is wheat, but theother grains, including corn, are also produced successfully. Othercrops have been tried with fair success, but not on a commercialscale. Grapevines have been made to grow quite successfully withoutirrigation on the bench lands. Several small orchards bearingluscious fruit are growing on the deep soils of the Great Basinwithout the artificial application of water. Though the firstdry-farming by modern peoples was probably practiced in the GreatBasin, yet the area at present under cultivation is not large, possibly a little more than four hundred thousand acres. 

Dry-farming, however, is well established. There are large areas, especially in Nevada, that receive less than ten inches of rainfallannually, and one of the leading problems before the dry-farmers ofthis district is the determination of the possibility of producingcrops upon such lands without irrigation. On the older dry-farms, which have existed in some cases from forty to fifty years, thereare no signs of diminution of soil-fertility. Undoubtedly, however, even under the conditions of extremely high fertility prevailing inthe Great Basin, the time will soon come when the dry-farmer mustmake provision for restoring to the soil some of the fertility takenaway by crops. There are millions of acres in the Great Basin yet tobe taken up and subjected to the will of the dry-farmer. 

Colorado and Rio Grande River Basins

The Colorado and Rio Grande River Basins include Arizona and thewestern part of New Mexico. The chief dry-farm crops of this drydistrict are wheat, corn, and beans. Other crops have also beengrown in small quantities and with some success. The area suitablefor dry-farming in this district has not yet been fully determinedand, therefore, the Arizona and New Mexico stations are undertakingdry-farm surveys of their respective states. In spite of the factthat Arizona is generally looked upon as one of the driest states ofthe Union, dry-farming is making considerable headway there. In NewMexico, five sixths of all the homestead applications during thelast year were for dry-farm lands; and, in fact, there are severalprosperous communities in New Mexico which are subsisting almostwholly on dry-farming. It is only fair to say, however, thatdry-farming is not yet well established in this district, but thatthe prospects are that the application of scientific principles willsoon make it possible to produce profitable crops without irrigationin large parts of the Colorado and Rio Grande River Basins. 

The mountain states

This district includes a part of Montana, nearly the whole ofWyoming and Colorado, and part of eastern Idaho. It is located alongthe backbone of the Rocky Mountains. The farms are located chieflyin valleys and on large rolling table-lands. The chief dry-farm cropis wheat, though the other crops which are grown elsewhere ondry-farms may be grown here also. In Montana there is a very largearea of land which has been demonstrated to be well adapted fordry-farm purposes. In Wyoming, especially on the eastern as well ason the far western side, dry-farming has been shown to besuccessful, but the area covered at the present time iscomparatively small. In Idaho, dry-farming is fairly wellestablished. In Colorado, likewise, the practice is very wellestablished and the area is tolerably large. All in all, throughoutthe mountain states dry-farming may be said to be well established, though there is a great opportunity for the extension of thepractice. The sparse population of the western states naturallymakes it impossible for more than a small fraction of the land to beproperly cultivated. 

The Great Plains Area

This area includes parts of Montana, North Dakota, South Dakota, Nebraska, Kansas, Wyoming, Colorado, New Mexico, Oklahoma, andTexas. It is the largest area of dry-farm land under approximatelyuniform conditions. Its drainage is into the Mississippi, and itcovers an area of not less than four hundred thousand square miles. Dry-farm crops grow well over the whole area; in fact, dry-farmingis well established in this district. In spite of the failures sowidely advertised during the dry season of 1894, the farmers whoremained on their farms and since that time have employed modernmethods have secured wealth from their labors. The importantquestion before the farmers of this district is that of methods forsecuring the best results. From the Dakotas to Texas the farmersbear the testimony that wherever the soil has been treated right, according to approved methods, there have been no crop failures. 

Canada

Dry-farming has been pushed vigorously in the semiarid portions ofCanada, and with great success. Dry-farming is now reclaiming largeareas of formerly worthless land, especially in Alberta, Saskatchewan, and the adjoining provinces. Dry-farming iscomparatively recent in Canada, yet here and there are semiaridlocalities where crops have been raised without irrigation forupwards of a quarter of a century. In Alberta and other places ithas been now practiced successfully for eight or ten years, and itmay be said that dry-farming is a well-established practice in thesemiarid regions of the Dominion of Canada. 

Mexico

In Mexico, likewise, dry-farming has been tried and found to besuccessful. The natives of Mexico have practiced farming withoutirrigation for centuries--and modern methods are now being appliedin the zone midway between the extremely dry and the extremely humidportions. The irregular distribution of the precipitation, the latespring and early fall frosts, and the fierce winds combine to makethe dry-farm problem somewhat difficult, yet the prospects are that, with government assistance, dry-farming in the near future willbecome an established practice in Mexico. In the opinion of the beststudents of Mexico it is the only method of agriculture that can bemade to reclaim a very large portion of the country. 

Brazil

Brazil, which is greater in area than the United States, also has alarge arid and semiarid territory which can be reclaimed only bydry-farm methods. Through the activity of leading citizensexperiments in behalf of the dry-farm movement have already beenordered. The dry-farm district of Brazil receives an annualprecipitation of about twenty-five inches, but irregularlydistributed and under a tropical sun. In the opinion of those whoare familiar with the conditions the methods of dry-farming may beso adapted as to make dry-farming successful in Brazil. 

Australia

Australia, larger than the continental United States, is vitallyinterested in dry-farming, for one third of its vast area is under arainfall of less than ten inches, and another third is under arainfall of between ten and twenty inches. Two thirds of the area ofAustralia, if reclaimed at all, must be reclaimed by dry-farming. The realization of this condition has led several Australians tovisit the United States for the purpose of learning the methodsemployed in dry-farming. The reports on dry-farming in America bySurveyor-General Strawbridge and Senator J. H. McColl have done muchto initiate a vigorous propaganda in behalf of dry-farming inAustralia. Investigation has shown that occasional farmers are foundin Australia, as in America, who have discovered for themselves manyof the methods of dry-farming and have succeeded in producing cropsprofitably. Undoubtedly, in time, Australia will be one of the greatdry-farming countries of the world. 

Africa

Up to the present, South Africa only has taken an active interest inthe dry-farm movement, due to the enthusiastic labors of Dr. WilliamMacdonald of the Transvaal. The Transvaal has an average annualprecipitation of twenty-three inches, with a large district thatreceives between thirteen and twenty inches. The rain comes in thesummer, making the conditions similar to those of the Great Plains. The success of dry-farming has already been practicallydemonstrated. The question before the Transvaal farmers is thedetermination of the best application of water conserving methodsunder the prevailing conditions. Under proper leadership theTransvaal and other portions of Africa will probably join the ranksof the larger dry-farming countries of the world. 

Russia

More than one fourth of the whole of Russia is so dry as to bereclaimable only by dry-farming. The arid area of southern EuropeanRussia has a climate very much like that of the Great Plains. Turkestan and middle Asiatic Russia have a climate more like that ofthe Great Basin. In a great number of localities in both Europeanand Asiatic Russia dry-farming has been practiced for a number ofyears. The methods employed have not been of the most refined kind, due, possibly, to the condition of the people constituting thefarming class. The government is now becoming interested in thematter and there is no doubt that dry-farming will also be practicedon a very large scale in Russia. 

Turkey

Turkey has also a large area of arid land and, due to Americanassistance, experiments in dry-farming are being carried on invarious parts of the country. It is interesting to learn that theexperiments there, up to date, have been eminently successful andthat the prospects now are that modern dry-farming will soon beconducted on a large scale in the Ottoman Empire. 

Palestine

The whole of Palestine is essentially arid and semi-arid anddry-farming there has been practiced for centuries. With theapplication of modern methods it should be more successful than everbefore. Dr. Aaronsohn states that the original wild wheat from whichthe present varieties of wheat have descended has been discovered tobe a native of Palestine. 

China

China is also interested in dry-farming. The climate of the drierportions of China is much like that of the Dakotas. Dry-farmingthere is of high antiquity, though, of course, the methods are notthose that have been developed in recent years. Under the influenceof the more modern methods dry-farming should spread extensivelythroughout China and become a great source of profit to the empire. The results of dry-farming in China are among the best. 

These countries have been mentioned simply because they have beenrepresented at the recent Dry-farming Congresses. Nearly all of thegreat countries of the world having extensive semiarid areas aredirectly interested in dry-farming. The map on pages 30 and 31 showsthat more than 55 per cent of the world's surface receives an annualrainfall of less than twenty inches. Dry-farming is a world problemand as such is being received by the nations.