DECOMPOSITION OF ORGANIC MATTER IN THE SOIL 383 



Hall concludes, therefore, that humus with a wide carbon-nitrogen 

 ratio is more valuable than humus with a narrow carbon-nitrogen ratio, 

 since the latter will be attacked more easily by the soil bacteria. Brown 

 and Allison indicate that there might be a possibility of applying ma- 

 terials of a wide carbon-nitrogen ratio to supply the deficiencies of 

 organic matter on the basis that the former may have the same or 

 better effect on bacterial activities such as azofication, or non-symbiotic 

 nitrogen fixation. 



THE TRANSFORMATION OF NITROGEN COMPOUNDS 



AMMONIFICATION. Experimental Study. By ammonification is 

 meant the production of ammonia by bacteria out of protein substances 

 or their cleavage products. That ammonia production in the soil is 

 a biological process was first demonstrated by Miintz and Coudon in 

 1893. These investigators showed that no ammonia is formed in sterile 

 soils. They also showed that ammonia may be produced out of nitro- 

 genous organic matter by molds as well as by bacteria. Marchal not 

 only confirmed these observations, but proved that various micro- 

 organisms differ markedly in their ability to produce ammonia. Of 

 the several species of bacteria tested by him, B. mycoides (one of the 

 common soil bacteria) proved itself particularly efficient in the breaking 

 down of nitrogenous materials and the production of ammonia. 



Since the publication of these experiments a large number of investi- 

 gators, both in Europe and America, have studied ammonia production 

 in culture solutions as well as in the soil itself. It has been shown that 

 under favorable conditions the breaking down of protein compounds and 

 the formation of ammonia may be very rapid; for instance, in some ex- 

 periments carried out by Lipman and his associates the following pro- 

 portions of nitrogen were transformed into ammonia in the course of 

 six days: 



Dried blood 16 . 74 per cent 



Concentrated tankage 56.66 per cent 



Ground fish 47. 16 per cent 



Cotton-seed meal ; 4-95 per cent 



Bone meal 16 . 65 per cent 



Cow manure, solid and liquid excreta 32 .60 per cent 



Cow manure, solid excreta 5-39 per cent 



The experiments were carried out in equal quantities of soil and with 

 equivalent quantities of nitrogen in the different substances. It will 



