Soil Nitrate Studies 



277 



By reference to figure 1 it will be noticed that the fresh nitrate 

 content of the corn soil was highest of all soils throughout the season. 

 The highest point of nearly 25 parts per million was reached on July 

 15, after which date the nitrate content dropped off until the end of 



E: / w " 2 C Zw JL 3v^ 



Comparison of the effects of the various rotations on nitrification. 



the season. The increases on August 26 and September 23 can be ex- 

 plained by virtue of the rain immediately preceding those dates. 



The soil from the wheat plots was low in nitrates during May and 

 early June, but went up materially during latter June and early July, 

 reaching the highest point on July 15 as the corn soil did. The depres- 

 sion on August 12 was probably due to the extremely dry weather im- 

 mediately preceding that date. 



