FARM MANURES 



581 



ents they 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, 1 compiled from Ohio, Connecticut, and New York 

 (at Cornell University), illustrate this point clearly: 



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. 



