346 THE PRINCIPLES OF SOIL MANAGEMENT 



The number of pounds of each constituent per ton 

 of fertilizer is then found thus: 



Nitrogen as nitrate 4X20= 80 pounds per ton 



Nitrogen in fine bone 3X20= 60 pounds per ton 



Phosphoric acid, available. . . . 6X20 = 120 pounds per ton 

 Phosphoric acid, insoluble . . .22X20 = 440 pounds per ton 

 Potash, muriate 10X20 = 200 pounds per ton 



The trade values, as published by the fertilizer in- 

 spection authorities, are then applied to the several 

 constituents. 



Nitrogen, as nitrates 80 X. 185 = $14 80 



Nitrogen in fine bone 60 X .205 = 12 30 



Phosphoric acid, available 120 X .045 = 5 40 



Phosphoric acid, insoluble 40 X .040= 1 60 



Potash, muriate 200 X .045 = 9 00 



$43 10 



The computed value may then be compared with the 

 market price. It must be remembered that this is the 

 commercial value, and not necessarily the agricultural 

 value, which is determined by the profits from its use, 

 and will depend upon many other factors. For instance, 

 a soil markedly deficient in nitrogen will not respond to a 

 phosphate fertilizer alone to an extent which would 

 justify its use. 



214. Mixing fertilizers on the farm. It has been 

 shown by several of the Experiment Stations that the 

 raw materials may be purchased from the manufacturers 

 and mixed on the farm at a considerably lower cost than 

 they can be bought in fertilizer mixtures, and that the 

 results obtained from them are fully as satisfactory. 



