FERTILIZERS FOR CEREAL CROPS 2 19 



cereal crops, although they do not remove large 

 amounts of total nitrogen from the soil, require 

 special help in obtaining this element. There is, 

 however, a great difference among the cereals as to 

 power of assimilating nitrogen. Next to nitrogen 

 these crops stand most in need of phosphoric acid. 

 The humic phosphates are utilized by nearly all of 

 the cereals. 



296. Wheat. This crop is more exacting in its 

 food requirements than barley, oats, or rye. Wheat 

 is comparatively a weak feeding crop, and the soil 

 should be in a higher state of fertility than for other 

 grains. The extensive experiments of L,awes and 

 Gilbert have given valuable information regarding 

 the effects of manures on wheat. Their results are 

 given in the following table : 74 



AVERAGE YIELD OF WHEAT PER ACRE. 



Bushels. 

 No manure for 40 years ........................ 14 



Minerals alone for 32 years ..................... 15^ 



Nitrogen " " " " ..................... 23.1 



Farmyard manure for 32 years .................. 32f 



Minerals and nitrogen for 32 years 1 ............. 36^ 



1 86 pounds of nitrogen as sodium nitrate. 



2 86 " " " " ammonium salts. 



The food requirements of wheat are such that it 

 should be given a favored position in the rotation. It 

 may follow clover provided the clover sod is light 

 and is fall plowed. On some soils, however, wheat 

 does not thrive following a sod crop, as it takes nearly 

 a year for a heavy sod residue to get into suitable food 



