TRADE VALUES OF FERTILIZERS 47 



The following illustration shows a guarantee of the same mixed 

 fertilizer, on the basis of equivalents in combination, and on the basis 

 of actual constituents : 

 Guarantee on basis of equivalents in combination : 



Nitrogen (equivalent to ammonia), 2 to 3 per cent. 



Available phosphoric acid (equivalent to bone phosphate of lime), 16 to 20 



per cent. 

 Potash (equivalent to sulfate of potash), 6 to 8 per cent. 



Guarantee on basis of actual constituents : 



Nitrogen (total) 1.65 to 2.50 per cent. 



Phosphoric acid (available) 7.00 to 9.00 per cent. 



Potash (actual) 3.25 to 4.25 per cent. 



It will be observed that the guarantee in the one case means the same 

 as in the other. Different methods of stating guarantees should not 

 mislead those who will familiarize themselves with the terms used, and 

 with the conversion factors. 



In the case of the mixed fertilizers, the percentage of the constituent 

 elements that are given on the basis of equivalents represents the 

 amounts when they exist in combination with other elements, viz., 

 nitrogen, as ammonia; phosphoric acid, as bone phosphate; and 

 potash, as sulfate. 



Methods of Computing Trade Value of Fertilizers 

 Trade-values of plant-food elements in raw materials and chemicals, 1910. 



The trade-values in the following schedule have been agreed 

 upon by the Experiment Stations of Massachusetts, Rhode Island, 

 Connecticut, New York, New Jersey, and Vermont, as a result of 

 study of the prices actually prevailing in the large markets of these 

 states. 



These trade-values represent, as nearly as can be estimated, the 

 average prices at which, during the six months preceding March, the 

 respective ingredients, in the form of unmixed raw materials, could be 

 bought at retail for cash in our large markets. These prices also corre- 

 spond (except in case of available phosphoric acid) to the average whole- 

 sale prices for the six months preceding March, plus about 20 per cent 

 in case of goods for which there are wholesale quotations. 



