CHAPTER XXX 

 NITRIFICATION IN MANURES 



The formation of nitrates in the manure heap is 

 brought about by the same influences that lead to their 

 formation in the soil. In either case, the presence of 

 nitrogenous organic substance, and the presence of sufS- 

 cient moisture, warmth, and air is necessary. The pres- 

 ence, also, of some base Hke Ume, to combine with the 

 nitric acid formed by the bacteria, is required. Besides, 

 there must not be too great an excess of soluble or easily 

 decomposable organic matter, lest the nitrifying organ- 

 isms be injured thereby. 



These conditions are usually fulfilled in all culti- 

 vated soils. They are not fulfilled in the manure pile 

 until after the decay bacteria have partly accomplished 

 the decomposition of the manure. For this reason, 

 the formation of nitrates does not take place in fresh 

 manure, notwithstanding the presence of nitrifying 

 bacteria in the air and in the soil. Moreover, conditions 

 may be created favorable to the nitrification in the upper 

 layers of the heap, but unfavorable to it in the lower 

 layers. Under such circumstances, the nitrates may be 

 washed downward and reduced in the interior of the 

 heap. 



Nitrification in manure. — The early experience gained 



V (337) 



