181 



and the loss of leachings. 

 fig. 1. 



The system here described is illustrated in 



ft**; \3Sk •' 



F.a 1. 



The French method of keeping manure. 



It has been questioned whether the construction of expensive cisterns 

 for collecting the manure leachings repays the cost, but it is obviously 

 desirable from what has been said regarding the value of the liquid 

 manure and the desirability of promoting regular and uniform fermen- 

 tation of the manure, that the leachings should be saved and added to 

 the manure heap by some means. Stored separately, the liquid part 

 rapidly deteriorates and the solid part, from lack of moisture, is liable 

 to undergo " fire-fanging," or harmful fermentation. 



The nature and extent of fermentation in manure also depends to 

 Bonie extent on the composition of the manure, more particularly upon 

 the amount of nitrogen in a soluble form which it contains. The greater 

 the amount of soluble nitrogen the more rapid the fermentation. Urine, 

 as we have already seen, is rich in soluble nitrogenous compounds, and 

 this explains why it decomposes so rapidly. 



By fermentation manure decreases rapidly in bulk. The substance 

 of which it is composed are converted largely into water and gases, 

 principally carbonic acid gas, and where fermentation is not properly 

 controlled, nitrogen may escape either in the free gaseous state or aa 

 ammonia. The coarse materials of the manure are gradually decom- 

 posed and are dissolved to a considerable extent in the black liquid 

 which oozes out of the manure heap. The mineral matter (the phos- 

 phates, potash, etc.) is also rendered more soluble. When properly 

 controlled, therefere, fermentation is a valuable means of increasing 

 the availability of the fertilising constituents of manure, although it 

 decreases the bulk ; but when not properly controlled it seriously 

 reduces the value of the manure. 



Leaching of Manure. 



Leaching is the second cause of deterioration of manure. When 

 manure is exposed to the action of the elements and the leachings 

 allowed to drain away it rapidly decreases in value. Both the organic 

 and the mineral constituents originally present or which have been 

 made soluble by fermentation are carried off and lost. Experiments at 

 the New York Cornell Experiment Station indicated " that horse 

 manure thrown in a loose pile and subjected to the action of the ele- 



