179 



Fertilising constituents in one ton of litter. 







Phosphoric 



Potash. 





Nitrogen. 



acid. 



, 







Pounds. 



Pounds. 



Pounds. 



Dead leaves 



16 



6 



6 



Straw 



8 to 12 



4 to 6 



12 to 32 



Peat moss 



16 



Trace. 



Trace. 



Sawdust 



4 to 14 



6 



14 



Spent tan 



10 to 20 







Peat 



20 to 40 







The use of litter therefore tends to dilute manure rather than improve 

 its chemical composition, but it absorbs and hold the valuable liquid 

 parts and reduces the loss of ammonia. 



MANAGEMENT OF MANURE. 



We have seen that barnyard manure is a material which rapidly 

 undergoes change. Where it is practical to haul the manure from the 

 stalls and pan and spread it on the field at frequent intervals the losses 

 of valuable constituents need not be very great, but when (as in winter) 

 the manure must be stored for some time the difficulties of preservation 

 become greatly increased. 



Under these conditions, deterioration of manure results from two 

 chief causes, (I) Fermentation, whereby a certain amount of the nitro- 

 gen is lost, and (2) weathering or leaching, which involves a loss of 

 the soluble fertilising constituents, including potash and phosphoric 

 acid as well as nitrogen. 



Fermentation of Manure. 



The fermentation of manure is due to the action of minute micro- 

 scopic organisms which belong to two great classes, (1) those which 

 require an abundant supply of air (oxygen) and which die when de- 

 prived of oxygen — known as aerobic ferments ; (2) those which grow 

 without oxygen and die when exposed to it — known as anaerobic fer- 

 ments. 



The decomposition observed in the manure heap is due as a rule to the 

 combined action of these two classes of ferments. On the outer surface 

 of the heap, where the air circulates freely, the first class (aerobic) is 

 active, while in the interior of the heap, where the supply of air is 

 limited, the fermentation is due to the anaerobic ferments. The latter 

 soon run their course and cease to exist. Their functions seems to be 

 principally to break up the more complex substances of th9 manure and 

 prepare them for the further action of the aerobic ferments which finally 

 convert them into simpler compounds such as water, carbonic-acid gas, 

 and marsh gas. « 



Where the manure is compacted (as in deep stalls for instance) the 

 carbonic acid gas formed by fermentation soon permeates the mass so 

 completely as to entirely exclude the air, thus arresting fermentation. 

 In loose heaps into which air is freely admitted fermentation of the 

 aerobic form may go on indefinitely. 



