FEESH AND KOTTEN MANUKE. 37 



and phosphoric acid, calculated to (95 per cent) nitrate 

 of soda, and (97 per cent) sulphate of ammonia, and 

 (25 per cent) superphosphate, give respectively 57.25 

 to 96 Ib. nitrate of soda, 45 to 75 Ib. sulphate of 

 ammonia, and 35 to 79 Ib. superphosphate. That is, 

 in order to apply as much nitrogen to the soil as is 

 contained in one ton of nitrate of soda, we should 

 require to use from 23 to 41 tons of farmyard manure ; 

 similarly one tori of sulphate of ammonia contains as 

 much nitrogen as 30 to 50 tons farmyard manure. In 

 the same way one ton superphosphate of lime contains 

 as much phosphoric acid as 28 to 64 tons farmyard 

 manure. 



The value of rotten manure is, weight for weight, 

 greater than that of fresh manure. This is due to the 

 fact that, while the water increases in amount, the loss 

 of organic matter of a non-nitrogenous nature more 

 than counterbalances the increase in water ; the man- 

 ure, therefore, becomes more concentrated in quality. 

 The loss on the total weight, according to Wolff, in 

 the rotting of farmyard manure, should not exceed in 

 two or three months' time 16 to 20 per cent viz., a 

 sixth to a fifth of its entire weight. Not only, how- 

 ever, does the manure become richer in manurial in- 

 gredients, but the forms in which the manurial ingre- 

 dients are present in rotten manure are more valuable, 

 as they are more soluble. These statements must 

 not be taken as proving that it is more economical 

 to apply farmyard manure in a rotten condition than 



