454 MISCELLANEOUS FARM SUBJECTS 



as already suggested, to accumulate in the surface soil, where they 

 may work great injury to the plant. 



These objections to muriate of potash do not apply to the sul- 

 phate. Therefore, if the two forms are equally available it would 

 be advisable in case of soils containing a limited supply of lime to 

 use the sulphate instead of the muriate. If the muriate of potash is 

 used liberally it should be accompanied by periodical applications 

 of lime. 



AGRICULTURAL VERSUS COMMERCIAL VALUE OF FERTILIZERS. 



The agricultural value of any of the fertilizer constituents is 

 measured by the value of the crop increase which its use may be ex- 

 pected to produce. Knowing the average composition of wheat, we 

 may easily calculate the agricultural value of any given quantity of 

 plant food as tending to produce, under suitable conditions, a certain 

 increase in the yield of grain. The agricultural value of plant food 

 is not a fixed quantity. It is a variable factor, depending upon the 

 availability of the constituent or constituents, as well as depending 

 upon the value of the crop produced. The availability of any con- 

 stituent is, in turn, dependent on its origin, on its treatment, and on 

 the conditions of soil and climate under which it is applied, while 

 the value of the crop produced is affected by its character, by the dis- 

 tance from the point of consumption, and by the conditions of de- 

 mand and supply. It is quite evident, for instance, that the agricul- 

 tural value of a pound of soluble phosphoric acid is likely to be 

 greater than that of a pound of insoluble phosphoric acid, when ap- 

 plied under the same conditions of soil and crop, since in the one case 

 the constituent is in its most available form, while in the other it 

 is but slightly available. Furthermore, the soluble phosphoric acid 

 in question may exert its full effect and lead to a large increase in the 

 yield of certain crops without leading at the same time to increased 

 profits. In other words, the increase produced by the application 

 of the fertilizer may possess a value smaller than the cost of the 

 latter. On the other hand the same fertilizer when used in con- 

 nection with a crop possessing a greater market value may prove 

 highly profitable, since the monetary return secured from the crop 

 increase is much greater than the cost of the fertilizer. Hence it 

 should be remembered that slowly available materials can not be 

 expected to give profitable returns, particularly upon crops with a 

 short growing season, and that expensive materials can not yield 

 returns that are as remunerative with crops of relatively low value 

 as they are with crops of relatively high value. 



The agricultural value should not be confused with what is 

 termed commercial value or cost in market. The latter is deter- 

 mined by market and trade conditions, as the cost of the crude ma- 

 terials, the methods of their subsequent treatment, etc. Since there 

 is no strict relation between agricultural and commercial value, it fre- 

 quently happens that a constituent in its most available form, and 

 possessing under suitable conditions a high agricultural value, costs 

 less in the market than the same constituent in forms less available 

 and possessing a slighter agricultural value. It is clear, therefore, 



