^o. 4.] CHEMICAL AND FARM MANURES. 155 



Stable Manure, its Treatment and Application. 



Probably during no period of the century has so much 

 attention been paid to the investigation of stable manure 

 with special reference to the conservation of its nitrogen as 

 during the past two or three years. This has been largely 

 due to a prize offered by the German Agricultural Society 

 for the best investigation in this line. Owing to some of the 

 striking conclusions arrived at by certain German investi- 

 gators, Deherain in France and a large number of bacteriol- 

 ogists in various countries have also lent their aid to the 

 solution of this problem. The limits of several papers 

 •would be required to give the successive steps and details 

 of these investigations, so that only the briefest reference 

 can be made here to some of the main features and to the 

 practical outcome of the investigations. 



The losses of nitrogen from stable manure are essentially 

 due to two causes : — 



1. To the formation of ammonium carbonate in the proc- 

 ess of decomposition, and, finally, the escape of this ammo- 

 nia into the air in gaseous form. 



2. To a reduction of the nitrates and nitrites formed as a 

 result of the more or less complete nitrification of the ammo- 

 nia, by which nitrogen is evolved into the atmosphere in a 

 gaseous state. 



Early in the investigation of this question evidence was 

 brought forward indicating that the chief loss actually occurs 

 in the form of nitrogen gas as a result of the so-called proc- 

 ess of denitrification. Subsequent discussion and observa- 

 tion indicate however, that the losses as ammonia are more 

 serious. The losses in the first category were especially 

 studied by Professor Wagner and others, who found that 

 when manure was applied to the soil but little effect was 

 produced l)y the nitrogen, and, furthermore, it was found 

 that it even caused the denitrification and loss of the nitrogen 

 applied in connection with it as nitrates. It was quite gen- 

 erally supposed at that time that this was due to the presence 

 of unusual numbers of the denitrifying organisms in the 

 manure. Straw was subsequently found to cause the same 

 destruction, and was also looked upon as a bearer of these 



