FIKLD EXPERIMENTS WITH FERTII^IZERS. 



141 



last two columns of Table 72. The small benefit derived from 

 nitrogenous fertilizers is in striking contrast to the results ob- 

 tained with corn, as may be seen by comparing these figures 

 with those in corresponding columns of Table 68. 



Table 72. 



special nitrogen experiments on soy bean seed. 



Percentages and pounds per acre of dry matter and ofprotei?i. 



*The average of the yields on plots 6a and 6b is here taken as 100 for comparison. 

 SOIL TEST WITH SOY BEANS. 



The soil test of 1901 is the twelfth in a series that was begun 

 in i8go and has been continued year by year upon the same 

 plots, but with a four year rotation of crops, namely, corn, 

 potatoes, oats and either cow peas or S05' beans. The purpose 

 of the experiment is to study the deficiencies of the soil and the 

 demands of different crops for the different ingredients of fer- 

 tilizers. The general plan consists in dividing a field into 

 parallel plots, applying on the different plots fertilizers which 

 will supply nitrogen, phosphoric acid and potash singly and in 

 different combinations, and growing the same crop on all the 

 plots. The kinds and amounts of fertilizers per acre are nitrate 



