378 FARMING IN REGIONS OF LIMITED RAINFALL 



above fifteen inches. In some sections twelve inches or less of 

 rainfall is sufficient for dry-farming. The amount of rainfall during 

 the growing season is a better criterion of crop production than the 

 annual rainfall. 



Soils in Dry-Farming Regions. — Soils in dry and semi-arid 

 cUmates are rich, because of the comparatively small amount 

 of leaching during past ages. A great variety of soils exist — 

 ranging from heavy clay and alluvial loam to fine sand and 

 coarse gravel, and varying in depth from a few inches to many 

 feet. A dry-farm soil should be intermediate in texture, uniform 

 and deep, and should support a good growth of natural vegetation, 

 preferably sagebrush. 



The success of dry-farming is determined in a large measure 

 by the deep, congenial subsoils so generally characteristic of arid 

 and semi-arid regions. This enables the roots of crops to pene- 

 trate deeply, thus enabling them to secure deep as well as 

 broad pasturage. 



Farming Methods.- — ^Many wrong ideas have prevailed con- 

 cerning dry-farming methods. Recent experiments, however, 

 seem to warrant the following statements:^ 



(a) No definite ^'system" of dry-farming has been or is likely 

 to be established that will apply generally to all or to any con- 

 siderable part of the dry-land area. 



(6) No hard and fast rules can be adopted to govern the 

 methods of tillage or of the time and depth of plowing. 



(c) Deep tilling does not necessarily increase the water-holding 

 capacity of the soil or facilitate root development. 



(d) Alternate cropping and summer tillage can not be relied 

 upon as a safe basis for a permanent agriculture or to overcome 

 the effect of severe and long-continued droughts. 



(e) The farmer can not be taught by given rules how to operate 

 a dry-land farm. 



Crops for Dry-Farming.^ — In dry-land farming the selection 

 of proper crops and their proper seeding, care and harvesting are 

 as important as choosing a Suitable soil and preparing it properly. 

 In general, crops cultivated in humid regions are also grown on 

 semi-arid lands. However, varieties especially adapted to dry- 

 farming conditions must be used. In some sections it is most 

 important to select those crops which will make most of their 



^ United States Department of Agriculture Yearbook, 19 U. 



