598 SOILS: properties and management 



It is to be noted that the organic matter of the food 

 has sustained an average loss of about 55 per cent, while 

 the loss of nitrogen and of minerals has been 13 per cent 

 and 2 per cent, respectively. The loss of the organic 

 matter is especially serious, although it can be replaced by 

 using green manures and the practicing of a proper rotation. 

 The loss of nitrogen can be replaced only by the growing 

 of legumes or by the addition of a nitrogenous fertilizer. 



503. Losses due to leaching and fermentation. — As 

 about one-half of the nitrogen and two-thirds of the potash 

 in farm manures is in a soluble condition, the possibility 

 of loss by leaching is very great, especially where the 

 manure is exposed to heavy rainfall. The loss of phos- 

 phorus is also of some consequence. In addition, the 

 fermentation, especially that of an aerobic nature, will 

 cause the formation of ammonia, which may be lost in 

 large quantities if steps are not taken to control such 

 action. It is evident that losses by leaching may be 

 checked considerably by protecting the manures from 

 excessive rainfall and by providing tight floors in the 

 stable or an impervious bottom in the manure pit or 

 under the manure pile. Packing and moistening the 

 manure will change the aerobic fermentation to anaerobic, 

 thus reducing very markedly the production of ammonia 

 w y hile allowing a simplification of the manurial compounds 

 to proceed steadily. All wise methods of handling and 

 storing manures provide against these losses through 

 leaching and fermentation by protecting the manure from 

 rain and by controlling fermentation through moisten- 

 ing and compacting. 



It is very difficult, in quoting figures for w^aste of 

 manure, to separate the losses due to leaching from those 

 due to fermentation. The two processes go on simul- 



