276 



Proceedings of Indiana Academy of Science 



was reached on July 15. The incubated samples with ammonium sul- 

 phate showed much higher nitrification than those without, indicating 

 a deficiency in available nitrogenous materials in the soil. 



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6 



Fig. 1. Average fresh nitrates of the various crops. 



Comparison of the Averages of the Various Croi-s. 



The fresh nitrate content of the soils fiom all the plots in the 

 same crop were averaged for each date of sampling. The accompanying 

 graph shows these averages for the four crops. 



