252 AGRICULTURAL EXPERIMENT STATION. [Jan. 



that the particular brand of fertilizer in question actually 

 contains the guaranteed quantities and qualities of essential 

 articles of plant food at a reasonable cost, and that it con- 

 tains them in such form and such proportions as will best 

 meet existing circumstances and special wants. In some 

 cases it may be mainly either phosphoric acid or nitrogen or 

 potash ; in others, two of them ; and in others again, all 

 three. A remunerative use of commercial fertilizers can only 

 be secured by attending carefully to the above-stated con- 

 siderations. 



To assist farmers not yet familiar with the current mode 

 of determining the commercial value of manurial substances 

 offered for sale in our markets, some of the essential con- 

 siderations, which serve as a basis for their commercial 

 valuation, are once more stated within a few subsequent 

 pages. 



The hitherto customary valuation of manurial substances 

 is based on the average trade value of the essential fertil- 

 izing elements specilied by analysis. The money value of 

 the higher grades of agricultural chemicals and of the higher- 

 priced compound fertilizers depends, in the majority of cases, 

 on the amount and the particular form of two or three essen- 

 tial articles of plant food, i. e., phosphoric acid, nitrogen 

 and potash, which they contain. To ascertain by this mode 

 of valuation the approximate market value of a fertilizer 

 (i. e., the money worth of its essential fertilizing ingre- 

 dients), we multiply the pounds per ton of nitrogen, etc., 

 by the trade value per pound ; the same course is adopted 

 with reference to the various forms of phosphoric acid and 

 of potassium oxide. We thus get the values per ton of the 

 several ingredients, and, adding them together, we obtain 

 the total valuation per ton in case of cash payment at points 

 of general distribution. 



The market value of low-priced materials used for manurial 

 purposes, as salt, wood ashes, various kinds of lime, barn- 

 yard manure, factory refuse and waste materials of different 

 description, quite frequently does not stand in a close rela- 

 tion to the market value of the amount of essential articles 

 of plant food they contain. Their cost varies in different 

 localities. Local facilities for cheap transportation, and 



