1914] Lipman-Burgess : Ammonification in Soils by Pure Cultures 165 



there are but ten organisms which can accomplish that task, and 

 but seven such in the case of fish-guano nitrogen. 



From the point of view of availability by pure cultures 

 therefore in the sandy soil the four nitrogenous fertilizers are 

 to be rated as follows: cottonseed meal, tankage, dried blood, and 

 fish guano. The first two are nearly alike and are far superior 

 to the last two, which are nearly alike, but much more different 

 from each other than the first two. 



The greatest efficiency at ammonification manifested by any 

 organism in the sandy soil is that of B. mesentericus with tankage 

 nitrogen, which transforms 32.52 per cent of the nitrogen present 

 into ammonia in twelve days. It should be noted in this con- 

 nection also that absolutely higher amounts of ammonia are 

 produced from tankage nitrogen than from any other form in 

 the sandy soil, even if there are fewer organisms which attack 

 it readily than there are in the ease of the cottonseed meal. 



TJie Clay-Loam Soil 



Conditions are evidently entirely different for ammonification 

 in this soil. Not only is the ammonia production very low so 

 far as all the fertilizers are concerned, but they no longer bear 

 to one another the relation which obtained between them in the 

 sandy soil. There are thus but few organisms which possess the 

 power of transforming 10 per cent or more of the total nitrogen 

 in any of the four fertilizers into ammonia in twelve days. In 

 fact, there are none such in the case of the dried blood, only two 

 such each in the cases of cottonseed meal and fish guano, and 

 seven such in the case of the tankage. No organism attains to 

 the production of ammonia equivalent to 13 per cent of the total 

 amount present in the clay-loam soil regardless of the kind of 

 fertilizer at its disposal. 



The tankage, however, is superior to the cottonseed meal in 

 the clay loam and distinctly so as above indicated. The cotton- 

 seed meal takes second place, the fish guano third place, and the 

 dried blood is by far the poorest. Indeed, no organism was 

 capable of producing an amount of ammonia in excess of 6.91 



