298 DRY-FARMING 



The persistent application of the proper cultural 

 methods of dry-farming will set free the most im- 

 portant plant-foods, and on well-cultivated farms 

 nitrogen is the only element likely to be absent in 

 serious amounts. 



The rotation of crops on dry-farms is usually 

 advocated in districts like the Great Plains area, 

 where the annual rainfall is over fifteen inches and 

 the major part of the precipitation comes in spring 

 and summer. The various rotations ordinarily 

 include one or more crops of small grains, a hoed 

 crop like corn or potatoes, a leguminous crop, and 

 sometimes a fallow year. The leguminous crop is 

 grown to secure a fresh supply of nitrogen ; the hoed 

 crop, to enable the air and sunshine to act thoroughly 

 on the soil grains and to liberate plant-food, such as 

 potash and phosphoric acid ; and the grain crops to 

 take up plant-food not reached by the root systems 

 of the other plants. The subject of proper rotation 

 of crops has always been a difficult one, and very 

 little information exists on it as practiced on dry- 

 farms. Chilcott has done considerable work on 

 rotations in the Great Plains district, but he frankly 

 admits that many years of trial will be necessar}- for 

 the elucidation of trustworthy principles. Some of 

 the best rotations found by Chilcott up to the present 

 are: — 



Corn — Wheat — Oats 



Barley — Oats — Corn 



Fallow — Wheat — Oats 



