USE OF CONCENTEATED FERTILIZERS. 129 



four pounds of phosphoric acid ; its agricultural value, as a 

 general rule, stands higher than any commercial artificial fer- 

 tilizers, containing these sul3stances in the proportion previ- 

 ously stated ; for stable manure does not only add plant- 

 food ; it acts, also, beneficially on the physical condition of 

 the soil. 



The only serious objection which can be urged against the 

 exclusive use of stable manure for fertilizing purposes in a 

 mixed general farm manasrement consists in the fact that it 

 usually becomes, sooner or later, an incomplete manure for 

 the crops under cultivation, in consequence of the more or 

 less general practice of selling various kinds of farm produce, 

 without restoring in some suitable form to the soil, at least 

 their ash constituents. 



There are two ways by which barn-yard manure may be 

 made a complete fertilizer for any farming system, and they 

 are : to restore either the soil constituents, sold in the farm 

 produce, by buying rich food in addition to the fodder-crops 

 raised, or by securing an efficient amount of a suitable com- 

 mercial concentrated fertilizer. "VVh'ch of these two courses 

 will be the most economical, cannot be well decided on mere 

 general principles beyond the statement that, the first course, 

 the buying of strong food, seems to be the safest and most 

 efficient, in general farm management; whilst the second 

 course, the buying of concentrated commercial fertilizers, de- 

 serves quite frequently especial recommendation for the culti- 

 vation of certain industrial crops. 



Having within the previous pages thus attempted to render 

 somewhat more prominent the character and the value of 

 our home resources of nitrogenous fertilizers, I conclude with 

 a short enumeration of the cases, for which the application of 

 economical concentrated fertilizers is usually urged. 



To aid indirectly in a speedy production of an efficient 

 quantity of home fertilizer ; 



To render new land soon fertile ; 



To restore the fertility of exhausted lands with the least 

 delay ; 



To bring fertile lands to their maximum yield ; 



To correct the peculiar effects produced by a frequent culti- 

 17 



