COMMERCIAL FERTILIZERS AND THEIR USE 243 



with the actual value secured in increased yield from 

 the use of the fertilizer. 



291. Home Mixing of Fertilizers. At the New 

 Jersey Experiment Station it was shown that "the 

 charges of the manufacturers and dealers for mixing, 

 bagging, shipping, and other expenses are on the aver- 

 age $8.50 per ton, and also that the average manu- 



/ 2 



FIG. 44. Composition of Fertilizers. 



factured fertilizer contains about 300 pounds of actual 

 fertilizing constituents per ton. These figures are prac- 

 tically true of other states, where large quantities of 

 commercial fertilizers are used." 72 In states where 

 smaller amounts are used the difference between the 

 estimated cost and selling price is greater than $8.50. 



These facts emphasize the* economy of home mixing. 

 The difference in price between the raw materials and 

 the product sold is frequently so great that it is an ad- 

 vantage for the farmer to purchase the raw materials, 

 as sulphate of potash, nitrate of soda, and acid phos- 



