AVAILABLE NITROGEN OP' THE SOIL. 



285 



TABLE m. 



TOTAJ- ASSIMILABLE NITROGEN (OF AMMONIA AND NITRIC ACID). 



From the first Table we gather that the quantity of 

 ammonia, which was considerable in the spring, dimin- 

 ished, especially in a porous (sifted) soil until September. 

 In the compnct earth of tlie uncultivated path, its diminu- 

 tion was less rapid and less complete. The amount of 

 nitric acid (nitrates), on the other hand, increased, though 

 not alike in any two cr.ses. It attained its maximum in 

 the hot weather of June, and thence fell off until, at the 

 close of the experiments, it was completely wanting save 

 in a single instance. 



The figures in the second Table do not represent the 

 absolute quantities of nitric acid that existed in the soil 



