soil moisture is conserved, while the seed bed is made smooth, view - 

 fine, and evn. Numerous small clods on the surface, how- 

 ever, may be of value in holding the snow on winter wheat 

 fields and in preventing or reducing soil washing. 



Deep plowing is not of general value and often seems to 

 affect the yield of straw more than the yield of grain. Plow- 

 ing from 4 to 6 inches deep is adequate, especially if the land 

 is in good tilth. Subsoiling is expensive and frequently 

 unprofitable in wheat culture. On friable and mellow soils 

 plowing is unneccessary if the land was well cultivated the 

 year before in connection with growing corn or other hoed crops. 

 On such land a seed bed can be prepared by disking or cultiv- 25 

 ating and harrowing. 



If the plowing is done when it is too wet the soil is likely to 

 harden or bake, and if done when too dry the ground remains 

 rough and lumpy. It should be remembered that in growing 

 wheat and other similar plants the tillage of the crop, as it 

 were, is performed before and at the time the seed is sown. In 

 the semiarid regions the success of the crop depends often 

 entirely upon the careful and thorough cultural treatment 



given the land. 



MANURING. 



The fertility of wheat land may be maintained and im- 

 proved by the use of barnyard manure, commercial fertilizers, 

 and green manures, and by proper crop rotations and fallowing. 

 No generally applicable rule for fertilizing wheat lands can be 

 laid down, but certain underlying principles are operative 

 everywhere. Wheat straw contains approximately 0.6 per 

 cent of nitrogen, 0.2 per cent of phosphoric acid, and 0.6 per 

 cent of potash, and the grain about 2 per cent of nitrogen, 

 0.85 per cent of phosphoric acid, and 0.55 per cent of potash. 

 This means that a ton of straw removes from the soil 12 

 pounds of nitrogen, 4 pounds of phosphoric acid, and 12 

 pounds of potash, and a ton of grain, or 33 J bushels, 40 pounds 

 of nitrogen, 17 pounds of phosphoric acid, and 11 pounds of 

 potash. These figures call attention to the importance of 

 returning at least the straw in the form of manure to the land 

 and also point to the fact that continued wheat growing for 

 the market must deplete the fertility of the soil. 



Barnyard manure is preferably applied to the corn crop 

 before wheat. When manure is directly applied to winter 

 wheat it should be spread and plowed under immediately 

 after the preceding crop is removed, in order that it may be- 

 come well embedded in the soil before the seed is sown. In 

 such cases the use of 10 tons per acre is sufficient and generally 

 27849 18 2 



