FERTILIZERS FOR CEREAL CROPS 221 



to nitrogenous manures. The experiments of Lawes 

 and Gilbert on the growth of barley are briefly sum- 

 marized in the following table. 75 



AVERAGE YIELD OF BARLEY PER ACRE FOR 34 YEARS. 



Bushels. 



No manure 17! 



Superphosphate alone 23^ 



Mixed minerals 24^ 



Nitrogen alone 3o| 



Nitrogen and superphosphate 45 



Farmyard manures .... 49*- 



298. Oats. Oats are capable of obtaining food un- 

 der more adverse conditions than either barley or 

 wheat. They are also less exacting as to the physical 

 condition of the soil. The oat plant will adapt itself 

 to either sandy or clay soil, and will thrive in the 

 presence of alkaline matter or humic acid where 

 wheat would be destroyed. In a rotation, oats usually 

 occupy a position less favored by manures. Oats are, 

 however, greatly benefited by fertilizers particularly 

 by those of a nitrogenous nature. 



299. Corn. Experiments with corn indicate that 

 under ordinary conditions it requires most help in ob- 

 taining phosphoric acid. Corn removes a large amount 

 of gross fertility but its habits of growth are such that 

 it generally leaves an average soil in better condition 

 for succeeding crops. Corn is not injured as are many 

 grain crops by heavy applications of stable manure. 

 It does not, like flax, produce waste products which 

 are destructive to itself. Rich prairie soils when 

 newly broken give better results for wheat culture 



