"8 THE MANURE HEAP AND SEWAGE 
soit ground, large amounts of this are completely lost by draining 
away or soaking into the ground. If the manure is left exposed to 
rains this loss is greatly increased. As a result the ordinary ma- 
nure heap decreases very much in value during the weeks or months 
that it is stored in the pile. This part of the loss can be entirely 
prevented by storing the manure where the liquids will not leach 
into the soil. (2) By fermentation. This subject requires a more 
extended consideration. 
THE FERMENTATIONS OF MANURE 
Destructive.—The first chemical changes which go on are 
those of general decomposition. An ammoniacal fermentation is 
universal. The liquid manure is most rapidly decomposed by this 
fermentation, the substance undergoing in a very few days, some- 
times in a few hours, a reduction into ammonia compounds, as 
already mentioned above. Eventually the nitrogenous com- 
pounds in the solid manure will also undergo ammoniacal fermen- 
tation. The starches, sugars, cellulose and woody tissue undergo 
a decomposition by which COs is set free and various other sub- 
stances are left. The fats and fatty acids are also decomposed, 
liberating CO with other less known bodies. The decomposition 
of the proteids liberates sulphur, commonly as HS, and this 
may unite with water to form sulphuric acid. The sulphuric acid 
may combine with the ammonia to form ammonium sulphate, or 
the ammonia may combine with the carbon to form carbonates. 
A large quantity of material is lost from the manure during these 
changes. The loss includes carbon in large amount, a matter of 
no significance, however, as it has simply gone into the air from 
which it can readily be reclaimed by plants. But the loss includes 
much nitrogen, and this is a misfortune, since it is the nitrogen that 
the farmer desires to keep. 
This loss occurs in several ways. (1) Liberation of ammonia. 
Since the ammonia resulting from decomposition is a gas, it will, to 
a considerable extent, dissipate itself at once into the atmosphere. 
