114 AGRICULTURE 



the nitrogen and some of the phosphoric acid and potash. Its 

 loss may be prevented by the use of the proper quantity and 

 kind of absorbents, such as straw or leaves, to catch and retain it. 



Second: Manure loses by exposure to rain. The liquid and 

 some of the elements of the solid matter are leached and washed 

 out. In manure exposed for several months to the weather, 

 the loss of nitrogen and potash may amount to more than one 

 half. When it is not desired to apply manure at once, it should 

 be piled under cover or composted and kept moist. 



Third: Manure loses through the escape of gases in fermenta- 

 tion, or ' heating ' as it is called from the heat produced and 

 given off in the process of decay. Fermentation is caused by 

 the action of bacteria. If they are allowed to work unchecked, 

 they set free in gases the most valuable elements of the manure. 

 The process of fermentation can be checked by mixing the manure 

 of different kinds of animals and by keeping the mass moist 

 and well packed. When it is kept moist, the heat, instead of 

 causing fermentation, is spent in evaporation; when it is well 

 packed and trampled, fermentation is checked by lack of air. 

 Manure is improved by fermentation if it be protected against 

 loss of nitrogen. 



Composting Manure. Farmers often compost manure. This 

 is done by making a heap composed of alternate layers of manure 

 and of weeds, leaves, etc. The whole is put up in a cone-shaped 

 heap to protect it against rain, and covered with a layer of dry 

 earth to absorb gases. It needs to be occasionally repiled and 

 wet thoroughly to keep in check the process of fermentation. 



Where labor is scarce, it is often better to haul manure directly 

 to the field where it is to be used, and to scatter it upon the 

 land so as to let its fertilizing elements be embodied in the 

 surface soil. 



