FARM MANURES 



581 



ents thev decompose so slowly as to make them somewhat 

 objectionable on light soils. Leaves decompose readily, 

 but add little fertility. Oat straw carries no more nitro- 

 gen than does average manure, and this nitrogen, like 

 that of peat or muck, is not readily available as plant- 

 food. Litter, however, is of such extreme importance as 

 an adsorbent that the resistant qualities of even such 

 materials as shavings can be to a degree ignored. Be- 

 cause of the influence of the bedding on composition, 

 manure should never be bought unless this phase has 

 been carefully looked into. 



484. Class of animal. — The second factor causing 

 radical variation in the composition of farm manure is 

 the class of animal by which it is produced. The following 

 figures,^ compiled from Ohio, Connecticut, and New York 

 (at Cornell University), illustrate this point clearly: — 





Pjercentagb op 





H20 



N 



P 



K 



Horse manure with straw 

 Cow manure with straw 



62.80 

 78.00 



0.57 

 0.46 



0.12 

 0,13 



0.54 

 0.36 



A working horse on maintenance ration will return in 

 the manure almost all the nitrogen and minerals taken 

 as food. In other words, the building-up and the break- 

 ing-down, or elimination, processes are about equal. 

 A young fattening pig, on the other hand, will return only 

 about 85 per cent of the nitrogen received as food and 96 

 per cent of the mineral material, and a milking cow 75 

 per cent and 89 per cent, respectively. 



1 Thorne, C. E. Farm Manures, p. 89. New York. 1914. 



