We have the required percentages of Nitrogen, available Food for 



phosphoric acid, and potash, but instead of i ton of 2,000 ! 



pounds we have only 1,273^ pounds of materials. We ^^ 

 may add 721^/ pounds of land plaster, peat, coal ashes, or 

 loam to make up the ton. 



This formula illustrates the question often raised by 

 farmers: "Why does the sum of the fertilizing constituents 

 in the analysis of a fertilizer amount to so much less than 

 the total weight of the fertilizer, and what is used by the 

 manufacturer to make up the difference.^" We find that 

 when the percentages of Nitrogen, total phosphoric acid, and 

 potash are added together, the sum of thei-r weights range 

 between 16 and 30 per cent, of the total weight, and that in 

 each ton of iertilizer there is from 70 to 84 per cent, of 

 something else. This great difference is not due to dishon- 

 esty on the part of manufacturers or dealers in agricultural 

 chemicals. The essential elements are always combined 

 with other substances which often are of no use whatever to 

 growing crops. Thus, in 100 pounds of Nitrate of Soda 

 we have only 15.75 pounds of Nitrogen and 84.25 pounds of 

 sodium, oxygen, and moisture, and so it is with all other 

 constituents of fertilizers — the greater part of the weight is 

 made up of moisture, dirt, etc. In many States of the 

 Union there is much greater protection against fraud in 

 buying commercial fertilizers than in the purchase of food 



or clothinor. 



... . . . / 



But commercial fertilizers or raw materials, for mixing, 



should never be bought except upon guaranteed analyses, 

 and with strict regard to soil requirements and the character 

 of the crop to be fed. 



In the above formula we might slightly change the per- 

 centages of fertilizing constituents, and probably get a better 

 crop effect by the change. We might drop out the muriate 

 of potash and reduce the sulphate of potash to 50 pounds, 

 and then substitute 821 i pounds of unleached wood ashes 

 for the sulphate and muriate of potash left out. In the 

 wood ashes there will be 45.21 pounds of potash and 

 15.20 pounds of phosphoric acid. Our formula would 

 then stand: 



