426 



T. L. HILLS 



TABLE 3 



Ammonia and nitrate in untreated, heated, and heated and reinoculated soils 



As expected the ammonia content in the untreated soil re- 

 mained quite constant while the nitrate increased. In the heated 

 soil where the nitrifying bacteria and the protozoa were absent, 

 the ammonia increased and the nitrate content remained prac- 

 tically the same. A part of the initial increase of ammonia 

 in the heated and in the heated and reinoculated soils is undoubt- 

 edly due to the heating alone. The bacteria surviving this 

 treatment cause some increase in ammonia as seen by the re- 

 sults obtained. But in the heated soil which was subsequently 

 reinoculated with 1 per cent normal soil the ammonia decreased, 

 due no doubt to its oxidation by the nitrifying bacteria, and the 

 nitrate nitrogen increased. In the latter instance the protozoa 

 were present, a factor which Russell and Hutchinson claim is 

 detrimental to bacterial activity. The nitrifying bacteria were 

 also present and active. 



The following table compiled in the same manner as table 2 



TABLE 4 



Total ammonia and nitrate nitrogen in the untreated, heated, and heated and 



reinoculated soils 



