PRINCIPLES OF MANURING 111 



With a possible choice of at least four 

 nitrogenous manures, varying somewhat in 

 composition and in price, it becomes of 

 importance that farmers should be able 

 intelligently to select the particular sub- 

 stance best adapted for their special require- 

 ments. Up to the present the choice has 

 lain almost exclusively between nitrate of 

 soda and sulphate of ammonia, and on the 

 basis of equal quantities of nitrogen there are 

 special circumstances that point to the one 

 rather than the other as being best suited for 

 any particular case. Something depends upon 

 the crop to which the manure is to be applied. 

 Speaking generally, nitrate of soda acts better 

 than sulphate of ammonia as a top-dressing, 

 partly because when one top-dresses a crop 

 one desires immediate action, and this is got 

 from nitrate of soda, and partly because it 

 sinks more quickly and more deeply into the 

 ground and so comes more effectively 

 within the range of the roots of the plants. 

 Moreover, when a crop already occupies ground 

 to which manure is applied, chances of 

 waste are reduced to a minimum, and this is a 

 consideration of greater importance in regard 

 to nitrate of soda than to any other manure 

 except nitrate of lime. Sulphate of ammonia, 

 on the other hand, is " fixed " or " absorbed " 



