No. 4.] COMMERCIAL FERTILIZERS. 123 



This is also an evidence that plants in their growth remove 

 from the soil a considerable portion of this compound. 

 Potash, however, differs from the other constituents men- 

 tioned in that the form in which it exists does not measure 

 its rate of availability, as is the case of nitrogen and phos- 

 ])horic acid, but has a greater bearing upon the effect upon 

 the soil and the quality of the produce. That is, potash 

 exists in practically two forms — chlorides and sulphates. 

 Muriate of potash is a chloride; kainit contains a mixture 

 of sulphate combined with ])otash and chlorides containing 

 magnesia and soda, thus making it in its effect upon soils 

 quite similar in character to the muriates. The sulphate, 

 however, though not quite as soluble, does not possess any 

 qualities which render its application to crops superior to 

 the other forms, so far as availability is concerned. It does, 

 however, possess qualities which make it superior to muriate 

 upon quality, for crops like potatoes, tobacco, sugar beets and 

 small fruits muriates should be eliminated as far as possible 

 because of their influence upon the quality of the product. 

 The benefits of potash free from muriates has been clearly 

 shown by the experiments conducted in your o\\'n State and 

 Connecticut. 



These facts, briefly stated, are the basis of our knowledge 

 concerning fertilizer materials, and measure what we under- 

 stand to be agricultural value. It does not follow that that 

 form of nitrogen, phos])horic acid or potash which is the 

 best is the cheapest in the market ; nor does it follow that the 

 cheapest is the best, — commercial values have absolutely no 

 bearing upon agricultural value. The agricultural value of 

 a fertilizer constituent is measured by the increase in crop 

 that may be derived from its use under well-known condi- 

 tions. Commercial value is based upon the business rela- 

 tions that surround the product, — the sources of supply, 

 cost of transportation, cost of manufacture, cost of delivery, 

 — all of these factors come in to fix the commercial value. 

 Many products of the higher value agriculturally are the 

 cheapest commercially and vice versa. Some of the ])oorest 

 products in the market, agriculturally, are selling at high 



