216 



Fertilisers 



[PT. Ill 



Thus for the first 400 lbs. of ammonium salts each 

 100 lbs. gives an additional 4| bushels of wheat and 

 5 cwts. of straw, together worth about 405. : the dressing 

 has therefore been profitable : when more ammonium salts 

 are added the increase given by each lOOlbs. is worth only 



A = Superphosphate. 



B = Mineral phosphate. 



C = Potash salts. 



D= Basic slag. 



E= Nitrate of soda. 



F = Sulphate of ammonia. 



G=: Potash salts (as pure 

 potash). 



H= Artificial nitrogenous 

 manures (nitrohm, 

 nitrate of lime), 



I = Peruvian guano. 



I I I 



Fig. 40. The world's annual consumption of artificial fertilisers (from 

 Production et Consommation dcs Engrais CImniques, Institut Inter- 

 national d' Agriculture, Rome, 1914). 



Each of the above columns is to be read from the base hne. 



about 205, which is less profitable and in pre-war daj^s un- 

 profitable. On other soils the point of diminishing profit 

 may come somewhere else, but there always is such a 

 point, and the farmer must be careful not to pass it. 



Application of artificial manures. The following points 

 are to be remembered : 



