THE DAIRY HERD 103 



Losses Through Fermentation. Manure is a medium 

 exceedingly rich in bacterial* life. Many species of bac- 

 teria are at work decomposing the organic matter, break- 

 ing up higher compounds into lower compounds and 

 accomplishing what is ordinarily designated the rotting 

 of the manure. In the fermentation or rotting process 

 the nitrogen compounds are broken up into ammonia, 

 which readily escapes from the manure pile. Evidence 

 of such escape is found in the ammoniacal odors that 

 emanate from loosely packed manure, such, for example, 

 as that procured from horses. 



This ammoniacal fermentation can be largely reduced 

 by packing the manure tight so as to exclude the air 

 as much as possible. Most of the bacteria concerned in 

 the liberation of ammonia must have air for their devel- 

 opment, and hence their action is reduced in proportion 

 as the air is excluded from the manure heap. 



On the other hand, some species of bacteria con- 

 cerned in the liberation of nitrogen, namely, the denit- 

 rifying bacteria, require no air for their growth and 

 development. Yet the loss from this class of bacteria 

 is relatively so small that, while the exclusion of air 

 favors their development, every effort should be made to 

 keep the manure heap as air-tight as possible, so as to 

 minimize the loss from the air-loving bacteria. 



Ammonia or Nitrogen "Fixers." While the loss of 

 ammonia from the manure heap can be materially reduced 

 by tight packing, more or less of it is bound to be formed 

 under the best packing possible. To prevent the escape 

 of this ammonia it is necessary to add to the manure 

 something which will "fix" or hold the ammonia. Mate- 

 rials used for this purpose are known as nitrogen or am- 



* For definition of bacteria, see page 146. 



