264 FARM MANURE 



formed by the decomposition of organic compounds of 

 potassium and other alkalies, including some ammonium 

 carbonate. Rain leaches out these soluble compounds as 

 well as soluble phosphates. There is consequently a decided 

 loss of potassium and phosphorus by leaching; of nitrogen 

 by volatilization as free nitrogen and as ammonia; and a 

 decrease in amount of organic matter due to volatilization 

 of carbon dioxide, hydrogen, and methane, and to leaching 

 away of humus compounds. The most serious loss, however, 

 is that of nitrogen, phosphorus, and potassium, and amounts 

 under such conditions to more than half of the original 

 content of these elements. Moreover, they are in the best 

 form, being soluble and available to plants. 



204. Prevention of Loss. — From the preceding discussion, 

 it can be seen that the greatest loss of nitrogen occurs under 

 aerobic conditions, while the loss of phosphorus and potas- 

 sium and some of the nitrogen occurs only when leaching 

 takes place. Since it is possible to retain a large part of the 

 volatile ammonia by chemical means as well as by producing 

 anaerobic conditions, methods of preventing loss of the 

 fertilizing constituents can be grouped under two general 

 heads: Mechanical and chemical. 



(a) Mechanical. — Since phosphorus and potassium in the 

 solid excrement, after being rendered soluble under either 

 aerobic or anaerobic conditions, are only lost by being 

 washed out of the manure pile, it is sufficient only to prevent 

 leaching by keeping the pile under cover, or in a water-tight 

 receptacle; or piled in such a way that leaching is reduced 

 to a minimum. This may be accomplished by making the 

 pile decidedly concave on top to hold the water that falls, 

 and building the sides vertical. 



Since a large part of the potassium and nitrogen are in the 

 urine and hence soluble, it is necessary to take precautions 

 which will prevent the urine from running off. Litter 

 accomplishes this purpose if employed in sufficient quantities, 

 and particularly if cut into short pieces — a practice which 

 increases the absorptive capacity of straw two or three times. 

 Rock phosphate sprinkled in the stalls before adding the 

 bedding also makes an excellent absorbent material. This 



