Loss in the Pile 309 



mentation is variable and is influenced by the compo- 

 sition of the manure as well as by the manner of storing. 

 When the manure is stored loosely, the aerobic bacteria 

 are favored in their growth. Their activities may be- 

 come so intense as to cause a rapid oxidation, that is, 

 a rapid burning up of the organic matter. Under such 

 circumstances, the temperature of the manure is raised 

 to a perceptible extent, frequently giving rise to fire- 

 fanging. Oxidation is mpre intense in the upper layers 

 of the manure on account of the more ready access of 

 oxygen to them. It has been demonstrated by actual 

 measurements that the temperature is highest near the 

 surface and lowest near the bottom of the pile. 



By compacting the manure and by largely excluding 

 thereby the access of air, the aerobic bacteria are sup- 

 pressed, and the anaerobic favored in their growth. 

 The decomposition then proceeds more slowly, the char- 

 acter of the chemical products is modified to a consid- 

 erable extent, and the losses diminished. Under different 

 conditions of storing, the losses of organic matter from 

 the manure pile in three or four months may range from 

 15 or 20 per cent to 40 or 50 per cent of the initial quan- 

 tity. Obviously, then, the value of manure as humus- 

 forming material is greater when it is kept well com- 

 pacted than it is when stored loosely. 



On light, sandy soils, in which the quantity of humus 

 is so important a factor in the maintenance of proper 

 moisture conditions, this difference is significant. To 

 take a concrete example, ten tons of fresh manure and 

 litter, containing 4,250 pounds of organic matter, may 

 be made to contain at the end of four months about 



