110 DRY LAND FARMING 



that which is furnished by crops while they are growing 

 or by vegetable matter in its decay on the soil which pro- 

 duced it. Sorghum in its growth, and especially in the 

 later stages of the same, furnishes a good illustration of 

 the former, and leaves from trees of the latter. The shade 

 thus furnished by sorghum in a considerable degree com- 

 pensates for the loss of moisture by transpiration through 

 the corn leaves. Such protection should be considered 

 when determining the crops that should be grown. Straw 

 from grain that is headed may furnish considerable shade, 

 and even the stubble from grain that has been harvested 

 may have an appreciable influence in reducing the loss 

 of moisture that falls upon them. Artificial shade is that 

 which comes from mulching, as by top dressing crops 

 with straw in the early stages of growth ; by top dressing, 

 especially pastures, with manure, or by using various 

 waste vegetable matters in covering the soil above the 

 roots of trees. Such measures, each in its place, may 

 render substantial service in reducing the loss of moisture 

 through evaporation. 



The seasonal use of moisture. What may be termed 

 the seasonal use of moisture considers adaptation in 

 plants: (1) to winter rainfall; (2) to spring or early sum- 

 mer rainfall, and (3) to rainfall conditions that are vari- 

 able. Close attention to such adaptation has an im- 

 portant bearing upon production in dry areas. 



When the precipitation occurs mainly in the winter, 

 it is important that such crops shall be grown as will 

 profit most by such winter rainfall. These crops include 

 wheat, winter rye, winter oats, winter vetch, winter bar- 

 ley, and to a less extent winter speltz. The crops which 

 are carried through the late autumn, winter and spring 

 months, are thus enabled to utilize the moisture that falls 

 in the seasons named, as spring sown crops could not util- 

 lize the same. Fortunately, these winter crops are chiefly 

 grown in climates, the severity of which does not preclude 



