142 



SOILS AND FERTILIZERS 



tains about 75 per cent, of water. The nitrogen va- 

 ries from 0.4 to 0.9 per cent. , according to the nature of 

 the food and the extent to which other factors have af- 

 fected the composition. In general, animals consu- 

 ming liberal amounts of coarse fodders produce manure 



-4. £.1-3. 4.2.1.3. 



Fig. 24. Average composition of Fig. 25. Manure after six 



fresh manure. months' exposure. 



1. Nitrogen. 2. Phosphoric acid. 

 3. Potash. 



with a higher per cent, of potash than of phosphoric 

 acid. This is because the potash in the food exceeds 

 the phosphoric acid. The average composition of 

 mixed stable manure is about as follows : 



Average. 

 Per cent. 



Nitrogen 0.50 



Phosphoric acid 0.35 



Potash 0.50 



Range. 

 Per ceut. 



0.4 to 0.8 



0.2 to 0.5 



0.3 to 0.9 



111 calculating the amount of fertility in manures, it 

 is more satisfactory to compute the value from the food 

 consumed and the care which the manure has received, 

 than to use figures expressing average composition. 



