46 FERTILIZERS 



The sulphate and muriate of potash will analyze 

 in round numbers about 50% actual potash (some- 

 times expressed as K2O). In other words it takes 

 two pounds of sulphate or muriate of potash to 

 make one pound of actual potash (K2O). When an 

 analysis states : "Sulphate of potash 8%, actual 

 potash 4%," it means simply that there is only 4% 

 of actual potash in the ton, or 80 pounds, and that 

 the manufacturers used 8% or 160 pounds of sul- 

 phate of potash to get it. The actual potash is 

 worth about six cents per pound, while the sulphate 

 is worth only three cents per pound. 



When both terms are used in stating the analysis, 

 only one of them should be included in the estimate 

 of the value of a ton. 



COMMERCIAL VS. AGRICULTURAL VALUE. 



67. Farmers frequently confound the agricultural 

 and commercial value of a fertilizer. If one is high 

 it does not necessarily imply that the other must be. 



The commercial value of any commodity is its 

 market price, its purchase price, and depends entirely 

 upon "supply and demand." 



The agricultural value of a fertilizer is its ability 

 to improve the fertility of the soil and the condition 

 of the crop in question. 



As an illustration, suppose a steady, long-lived 

 food were wanted for some perennials as an orchard, 

 blood would answer the purpose while nitrate of 

 soda would be soon exhausted or lost by leaching. 

 Now, if the price of both nitrate and blood is about 

 the same, the agricultural value of blood is far 

 greater. If a quickly acting manure was wanted, 

 the nitrate of soda would have the higher agricul- 

 tural value. 



