446 SOILS: PROPERTIES AND MANAGEMENT 



conditions that are likely to result in its loss from the 



soil. 



366. Ammonification. — Decay and putrefaction may 

 be considered as the beginning of the process of ammoni- 

 fication. Ammonification (see Fig. 61), as its name 

 implies, is that stage of the process during which am- 

 monia is formed from the intermediate products. 



Like the other processes of decomposition, there are 

 many species of bacteria capable of forming ammonia 

 from nitrogenous organic substances. Different forms 

 display different abilities in converting nitrogen of the 

 same organic material into ammonia, some acting more 

 rapidly or more thoroughly than others. In tests by 

 certain investigators in which the same bacteria are used 

 on different substances, the order of their efficiency is 

 changed with the change of substance. It, seems likely, 

 therefore, that certain forms are most efficient when 

 acting on certain organic compounds; that, in other 

 words, each species is best adapted to the decom- 

 position of certain substances, while capable of attack- 

 ing others although less effectively. This characteristic 

 preference of a class of bacteria for the decomposition of 

 certain substances is made evident by the experiments 

 of Sackett, 1 who found that in some soils dried blood was 

 ammonified more rapidly than was cottonseed meal, while 

 in other soils the reverse was true. 



367. Bacteria and substances concerned in ammoni- 

 fication. — Among the bacteria producing ammonifica- 

 tion are B. mycoides, B. subtilis, B. mesentericus vul- 

 gatus, B. janthinus, and B. proteus vulgaris. Of these, 

 B. mycoides has been very carefully studied, and the 



1 Sackett, W. G. The Ammonifying Efficiency of Certain 

 Colorado Soils. Colorado Agr. Exp. Sta., Bui. 184. 1912. 



