162 



SOIL PHYSICS AND MANAGEMENT 



by-products of the farm; however, sufficient manure cannot be 

 produced from the crops grown on the farm to maintain the supply 

 of organic matter. This is due to the fact that a large amount of 

 the organic matter is destroyed during the process of digestion. 



Average Digestibility of Some Common Feeds l 



From the above table it is seen that in feeding hay about 40 per 

 cent of the organic matter, or 800 pounds per ton of hay fed, is 

 recovered in the manure, while with pasture grasses an average of 

 32 per cent, or 640 pounds per ton, is recovered. In the feeding of 

 straw, shock corn or even ensilage, the animals leave a considerable 

 amount, so that somewhat more organic matter is recovered than 

 indicated by the figures. 



The amount and composition of manure produced by different 

 animals vary quite widely. The following table gives the amount: 



Amount and Value of Manure, Solid and Liquid, Excreted by Various Farm 

 Animals per 1000 Pounds of Live Weight 



Tn connection with this, attention is called to the next table, 

 which gives the composition of the manure: 



