1890.] PUBLIC DOCUMENT — No. 33. 233 



crop-producing value ; for the higher or lower market price 

 of difierent brands of fertilizers does not necessarily stand in 

 a direct relation to their particular fitness, without any 

 reference to the particular condition of the soil to be treated, 

 and the special wants of the crops to be raised by their 

 assistance. To select judiciously from among the various 

 brands of fertilizers offered for patronage, requires, in the 

 main, two kinds of information ; namely, we ought to feel 

 confident 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 contains them in such form and in 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 fertili- 

 zers can only be secured by attending carefully to the 

 above-stated considerations. 



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 valu- 

 ation, are once more stated within a few subsequent pages. 



The hitherto customary valuation of manurial substances 

 is based on the average trade value of essential fertilizing 

 elements specified 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 

 essential 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 

 ingredients), 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. 



