350 SOILS 



other kinds and are relatively poorer in plant 

 food, especially in nitrogen. An average sample 

 of either contains about 4 per cent, of nitro- 

 gen, 2 per cent, of phosphoric acid, and 5 per 

 cent, of potash. 



Sheep manure is commonly richer than the 

 manure of any other farm animal, except poultry. 

 It is comparatively dry and since it is usually al- 

 lowed to accumulate in pens, where it is tramped 

 hard by the animals, it is less apt to suffer a loss of 

 plant food than other kinds. Ordinarily it con- 

 tains about 8 per cent, of nitrogen, 2 per cent, of 

 phosphoric acid, and 7 per cent, of potash. 



Poultry manure is the richest of farm manures, 

 largely because it contains the semi-solid urine, 

 and mere is little waste. It is especially rich in 

 nitrogen and phosphoric acid. An average sample 

 contains 12 per cent, of nitrogen, 9 per cent, of 

 phosphoric acid and 6 per cent of potash. 



Average values for different manures are : Sheep 

 manure, $4.20 per ton; mixed farmyard manure, 

 $2.25 per ton; hen manure, $6.50 per ton; hog 

 manure, $3.20 per ton; livery-stable manure, $2.45 

 per ton; cow manure, $2.43 per ton. These figures 

 are based solely on their plant food content and do 

 not consider the value of the manure for improving 

 the soil in other ways. 



THE QUALITY OF MANURE 



The age and the condition of the animal influence 

 the quality of manure. Manure from young ani- 

 mals is not as rich as that from full grown animals, 

 because the former digest a larger proportion of 

 their food than the latter. Cows in milk return 

 only about 65 to 75 per cent, of the manurial value 



