74 THE CEREALS IN AMERICA 



119. Rotations. — The rotation of crops has been shown to 

 be absolutely essential to the profitable use of commercial 

 fertilizers.* Rotations are greatly modified in different localities 

 both by the crop producing capacity of the soil and by economic 

 causes. Wheat is frequently grown because it cannot well be 

 omitted from certain otherwise successful rotations. In many 

 sections for seeding land to timothy and clover, no other crop 

 combines so many advantages. 



The five course rotation of maize, oats and wheat, each one 

 year, and timothy and clover two years, is considered standard in 

 many sections. In this rotation stable or farm yard manure is 

 applied to the land before plowing for maize at the rate of about 

 twenty loads per acre. On what is known as maize land, the 

 residual effect of this manuring is usually sufficient to grow a 

 good crop of wheat, provided other conditions, such as climate, 

 rainfall and insect enemies, are not unfavorable. On the more 

 tenacious light colored clay soils, a light application (say twenty- 

 five pounds) of phosphoric acid (P2O5) is applied at the time of 

 seeding the wheat. A slight modification of the above is the 

 four course rotation of maize, oats, wheat and clover, each one 

 year. A still further modification is the three course rotation of 

 maize, wheat and clover, each one year. This is in regions not 

 well adapted to oats on account of climatic conditions and on 

 soil in which wheat can be successfully raised after maize without 

 plowing. (128) Sometimes mammoth clover is used and treated 

 as a seed crop. One of the most satisfactory rotations in its 

 effect upon the yield of wheat is the three course rotation of 

 potatoes, v'heat and clover, each one year. Where stable or 

 farm yard manure is available it is applied to the clover immedi- 

 ately after cutting the second crop in order to stimulate the 

 growth of clover to be plowed under either in the late fall or 

 early spring. In many cases the land is quite heavily fertilized 

 with commercial fertilizers at the time th^ DOtatoes are plantf»d, 



>■ Ohio BuL no (1899), p. 68. 



