MANURE 287 



If the heap is too loosely built, the fermentation is too rapid, and 

 large losses of nitrogen will occur. 



Moisture, by lowering the temperature and excluding air, re- 

 tards fermentation ; loss of manure is decreased by keeping the 

 manure properly moistened. Alternate wetting and drying is 

 also bad. 



Manure decreases rapidly in bulk during fermentation, the 

 substances of which it is composed being decomposed partly into 

 carbon dioxide and water. When the fermentation is not 

 properly controlled, nitrogen may escape as free gas or as am- 

 monia. The coarse materials are gradually decomposed and are 

 to a considerable extent dissolved in the black liquid which oozes 

 out of the manure heap. The mineral matter is also rendered 

 more soluble. 



The nitrogen in the liquid excrement is mostly present as urea 

 or hippuric acid. These undergo fermentation rapidly, especially 

 in a warm climate, producing ammonium carbonate, and con- 

 siderable amounts of ammonia may escape into the air. Ammonia 

 is produced in fermenting manure, and if the manure is 

 allowed to dry out, or is too freely exposed to the air, consider- 

 able losses of ammonia take place. 



Fermentation is controlled by keeping the manure heap com- 

 pact and moist, and by the use of preservatives. Sprinkling the 

 mass with water or liquid manure excludes air and prevents loss 

 of ammonia. If the mass dries out, nitrogen is lost. Gypsum 

 (land plaster), kainit, and acid phosphate are preservatives re- 

 commended to prevent loss of manure during fermentation, but 

 it is doubtful whether they have any appreciable effect. 



Methods of Saving Manure. The following are some methods 

 of saving manure: 



(i) Grlgnon Method. This method is used extensively in 

 France. The manure is piled upon a stone or cement pavement 

 in the farm courtyard, in flat, well packed layers. The liquid 

 manure, and the drainage from the manure pile runs into a stone 

 cistern. From time to time the liquid manure is pumped over the 

 pile of solids. The object of this is to keep the manure moist 



