Losses of Elementary Nitrogen 331 



The problem of the loss of nitrogen. — Numerous ex- 

 periments besides those already named may be cited 

 to show that such losses actually occur in liquid manure 

 when kept by itself in shallow vessels. Similar losses 

 are known to occur in culture solutions in the laboratory, 

 containing gelatin, peptone, or other nitrogenous or- 

 ganic substances. In the manure pile, however, where 

 the liquid manure is intimately mixed with the litter 

 and the solid excreta, the losses of ammonia are by no 

 means so extensive. The frequently large decrease in 

 the quantity of combined nitrogen must be attributed 

 to other causes. 



There are a considerable number of experiments on 

 record to indicate that, in many instances, the losses 

 of nitrogen from manure should be attributed largely 

 to the formation of free nitrogen gas in the course of 

 decay. We have already noted how the formation of 

 free nitrogen may occur in denitrification processes. 

 It has been pointed out, likewise, that in the manure 

 pile the losses of free nitrogen through denitrification 

 cannot be very large. 



There is, however, still another process through which 

 free nitrogen gas may be formed in the decomposition 

 of organic matter. It is the burning up of ammonia 

 with the formation of water, on the one hand, and of 

 elementary nitrogen on the other. Such burning up of 

 ammonia can take place only when the access of air 

 is very abundant, in other words, under pronounced 

 aerobic conditions. This process is contrary to denitr,i- 

 fication, the process whereby nitrates are destroyed 

 under conditions that are, for the most part, anaerobic. 



