54 FERTILIZERS 



High temperatures produce rapid decomposition, 

 especially in a loose heap, so that the rate of decay 

 maybe regulated by compacting the heap and sprink- 

 ling with water to exclude the air and reduce the 

 temperature. If compacted too tightly, decomposi- 

 tion may be too slow. Moderate fermentation is the 

 object desired. Loss of nitrogen, as ammonia, may 

 be detected by the strong odor arising, from the heap. 



If it is desired to obtain the benefits of the plant 

 food in manure quickly, it should be stored under 

 cover to prevent loss by leaching, and the tempera- 

 ture kept down by frequent wetting, and air ex- 

 cluded by settling the heap : decomposition may 

 thus take place with a minimum loss of ammonia. 

 If from one to two pounds of either gypsum, or sul- 

 phate of potash be sprinkled on the heap each day 

 as it accumulates from one or two animals, the am- 

 monia is converted to the sulphate form and thus 

 prevented from escaping. The gypsum must be 

 moist for this use to be effective. 



If, however, it is not desired to get the benefits of 

 plant food quickly, the manure had better be applied 

 fresh and incorporated with the soil at once. Decom- 

 position may be slower in such cases, but loss of 

 ammonia is surely prevented and a much better 

 mulch obtained. This is the most practical method. 



GREEN MANURING. 



82. The object of sowing the leguminous, or pod- 

 bearing plants is chiefly four-fold. 



1. For humus, which is always necessary for any 

 form of crop because of its various functions in the 

 soil, such as : (a) nitrification ; (b) Rendering insol- 

 uble forms of plant food available by the process of 



