274 



Proceedings of Indiana Academy of Science 



Discussion of Series 2 West (Corn, Wheat, Clover and Timothy). 



(Table IV.) 



The clover and timothy soil showed a low fresh nitrate content, 

 being especially low in May and the early part of June. The highest 

 point was reached immediately after the harvesting of the crop. In 

 comparing the incubated samples, it can be seen that the addition of 

 ammonium sulphate materially increased nitrification, which fact seems 

 to show that there was a deficiency of ea.sily available nitrogenous 

 materials. 



The corn plot reached its high point on July 15, and stayed rather 

 uniformly high until October 1. The addition of ammonium sulphate to 

 the incubated samples did not show much of an increase. This condition 

 may have been due, no doubt, to the fact that clover sod had been plowed 

 under, and there was, therefore, a fairly large supply of easily avail- 

 able nitrogen present. The ability of the nitrifying organisms to 

 change organic matter into nitrates was also probably enhanced about 

 this period. 



The fresh nitrates of the wheat soil were low in May and early 

 June, reached their highest points in July and early August, and then 

 fell off gradually. The presence of the clover in the stubble probably 

 caused the fresh nitrates to fall sooner than they otherwise would have 

 done. The addition of ammonium sulphate caused a marked increase 

 in the nitrification in the incubated samples, indicating a deficiency in 

 easily available nitrogenous materials. 



TABLE v.— Series 3 East 



Discussion of Series 3 East (Continuous Wheat). (Table V.) 



The two plots in this series have been in continuous wheat since 

 1889. Since 1911, plot 14 has received an application of lime every four 

 years, while plot 13 has received nothing. The fre.sh nitrate content 

 of both ran close during the whole season. The limed plot was slightly 



