1912] KeJIey: Biological Transformations of Nitrogen in Soils 43 



Table II. Effects of Calcium and Magnesium Carbonates on the 

 Ammonification op Dried Blood 



Ammonia nitrogen 

 Treatment mgs. 



None 81.4 



1 Gram Calcium Carbonate 84.3 



2 Gram Calcium Carbonate 8-5.0 



4 Gram Calcium Carbonate 91.0 



6 Gram Calcium Carbonate 91.0 



8 Gram Calcium Carbonate 87.8 



12 Gram Calcium Carbonate 87.8 



1 Gram Magnesium Carbonate 53.2 



2 Gram Magnesium Carbonate 53.9 



4 Gram Magnesium Carbonate 50.0 



These data, as all others submitted iu this paper, represent 

 averages of closely agreeing duplicates. In examining the above 

 data we note a slight stimulation in ammonia formation from the 

 use of the several amounts of calcium carbonate employed, the 

 maximum stimulation being reached with from 4 to 6 grams per 

 100 grams of soil. With the use of magnesium carbonate a marked 

 depression in ammonia accumulation occurred, there having been 

 found to be a falling off of approximately one-third as compared 

 with the amounts found without the use of carbonate. It is also 

 noteworthy that one gram of magnesium carbonate proved to be 

 about as toxic to ammonification as larger amounts. 



A second series was prepared with the use of still smaller 

 amounts of magnesium carbonate for the purpose of determining 

 the concentration at which toxic effects begin and also to deter- 

 mine the minimum amount of this carbonate necessary to produce 

 maximum toxicity. The results follow. 



Table III. Ammonification of Dried Blood as Affected by Small 

 Amounts of Magnesium Carbonate 



Ammonia nitrogen 

 Treatment mgs. 



None - 93.1 



0.1 Gram Magnesium Carbonate 77.4 



0.2 Gram Magnesium Carbonate 70.6 



0.4 Gram Magnesium Carbonate 65.6 



0.6 Gram Magnesium Carbonate 65.2 



0.8 Gram Magnesium Carbonate 64.6 



1.0 Gram Magnesium Carbonate 62.0 



