Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: able crops. The land is usually plowed two or three times, at intervals, or plowed once and harrowed two or three times. This procedure keeps down the weeds and increases the moisture in the soil. According to .King, 203 tons more water was found on fallowed land per acre in the spring following the fallow, than on land that was not fallowed, and 179 tons more water was found on the fallowed field after a crop was harvested than on the other field.1 Fallowing increases the supply of available nitrogen as nitrates and in some sections fallowing is practiced for this reason. The yield of the crop following fallowing is increased but considerable humus is lost by being oxidized, and generally more nitrates are formed than can be used up by the crop following fallowing. Snyder has found by experiments that 590 pounds of nitrogen per acre were lost by two years of summer fallowing, or an amount sufficient for five wheat crops.2 At the Roth- amstead Experiment Station experiments show that considerable more nitrogen was lost from bare soils than from wheat land. On rich soils the losses are greater than on soils deficient in organic matter because the. oxidation of humus is more rapid. It is evident, then, that fallowing increases the production of crops at the expense of a reduction of humus. In sections of plentiful rainfall, fallowing is often injurious and it should only be practiced in the dry sections where there is not enough rainfall to carry away the nitrates and therefore not sufficient moisture for the continuous growing of crops. Other Ways Nitrogen is lost,—The washing away of nitrogen as nitrates is not the only way this element is lost, but considerable of this valuable constituent escapes in the form of gases. This loss as gas is occasioned by denitrification...