200 SYSTEMS OF PERMANENT AGRICULTURE 



Thus, when pasture grasses containing one ton of dry matter 

 are eaten, only 580 pounds of the dry matter consumed will be re- 

 turned to the land in the droppings; and the manure made from 

 one ton of dry clover hay contains only 780 pounds of dry matter 

 instead of the 2000 pounds taken from the field. In other words, 

 a ton of clover plowed under will add nearly three times as much 

 organic matter to the soil as can possibly be recovered in the ma- 

 nure if the clover is fed. In the case of oat straw, about one half 

 is digested and one half recovered in the manure, while only one 

 tenth of the dry matter of corn is found in the manure. 



It must be kept in mind, furthermore, that to return even these 

 proportions of organic matter to the land requires that the manure 

 shall be applied to the soil before losses occur by fermentation and 

 decay. 



The Maryland Experiment Station allowed 80 tons of manure 

 to lie in an uncovered pile exposed to the weather for one year, 

 during which time the amount was reduced to 27 tons. 



Professor Shutt, Chief Chemist for the Experiment Stations of 

 the Dominion of Canada, exposed two tons of manure containing 

 1938 -pounds of organic matter, from April 29 to August 29, four 

 months, during which time the organic matter was reduced by 

 fermentation and decay to 655 pounds. During the same time the 

 nitrogen was reduced from 48.1 pounds to 27.7 pounds. 



In ordinary farm practice more or less loss of organic matter is 

 almost certain to occur unless the manure is applied to the soil 

 within a day or two after it is produced. 



Because the nitrogen of the soil is contained in the organic matter 

 and must be applied in that form in general farming, and because 

 the figures are available, the per cent of nitrogen digested is shown 

 in Table 27 for the common food stuffs named. The fact that 62 

 per cent of the nitrogen in red clover hay is digested means that 

 only 38 per cent of the nitrogen in the food consumed will be 

 recovered in the solid excrement. If the food ration consists of 

 equal parts of corn and clover hay, the solid excrement will contain 

 31 per cent, or less than one third, of the nitrogen in the food. 

 Of the remaining 69 per cent, about one third will be retained by 

 the animal (or secreted in milk) and two thirds excreted in the 

 liquid manure, as a general average in live-stock farming for animal 



