44 University of California Publications in Agricultural Sciences [Vol. 1 



These data are instructive as showing the marked depression 

 of ammoniflcation in the soil employed, even with the small 

 amount of .1 per cent of magnesium carbonate. The toxicity in- 

 creased with greater amounts of the magnesium carbonate added 

 reaching a practical maximum with from 0.8 to 1 gram per 100 

 grams of soil. 



According to Loew the toxic effects of an excess of magnesia 

 in soils can be overcome or antagonized by the application of 

 lime. "\Miile this theory was proposed and held for the higher 

 plants, it was thought to be of some interest to study the question 

 with reference to the ammoniflcation process. Accordingly the 

 following series of experiments was arranged. In these trials one 

 gram of magnesium carbonate per 100 grams of soil was used 

 throughout, this quantity having been found to l)e the lowest 

 that produced maximum toxicity. 



Table IV. AMiioNiFiCATioN of Dried Blood in the Presence of Both 



CaCo and MgCo 



3 3 



Ammonia nitrogen 

 Treatment mgs. 



1 Gram Calcium Carbonate 84..S 



1 Gram Magnesium Carbonate 53.9 



1 Gram Magnesium Carbonate + Of) Grams Calcium Carbonate 51.1 



1 Gram Magnesium Carbonate + 1. Grams Calcium Carbonate 53.9 



1 Gram Magnesium Carbonate + 2. Grams Calcium Carbonate 53.2 



1 Gram Magnesium Carbonate + 3. Grams Calcium Carbonate 50.6 



1 Gram Magnesium Carbonate + 4. Grams Calcium Carbonate 51.1 



1 Gram Magnesium Carbonate + 5. Grams Calcium Carbonate 50.7 



1 Gram Magnesium Carbonate + 6. Grams Calcium Carbonate 50.3 



1 Gram Magnesium Carbonate + 8. Grams Calcium Carbonate 50.7 



1 Gram Magnesium Carbonate + 12. Grams Calcium Carbonate 50.4 



From these data it is at once seen that no antagonism was 

 produced. Even the very large amount of 12 grams of calcium 

 carbonate in no way reduced the toxic effects produced by one 

 gram of magnesium carbonate. The results, therefore, are in 

 harmony with the observations made by Dr. C. B. Lipman^ in his 

 studies on the physiology of B. suhfilis. 



8 Loc. cit. 



