654 



Report on Inspection Work of the 



the following proportions of available phosphoric acid and potash in 

 the different grades: 



Class op Fertilizers. 



Potash. 



Low-grade . . 



Medium-grade 



Medium high-grade 

 High-grade 



3.2 

 2.9 

 3.8 

 2.1 



This form of statement clearly brings out the fact that fertilizers of 

 different grades differ not only in respect to the amounts of plant-food 

 contained in them, but that the different elements of plant-food bear 

 a different ratio to each other in the different grades. Thus, it is seen 

 that, as the grade becomes higher, the proportion of phosphoric acid 

 to nitrogen grows less, or, stated another way, the proportion of 

 nitrogen to phosphoric acid increases. In low-grade fertilizers, the 

 amount of phosphoric acid is 8 times as much as that of nitrogen, 

 while in the high-grade class there is about twice as much. In the 

 case of potash, the variation of the ratio of nitrogen to potash, while 

 noticeable, is not as great as in the case of the ratio of nitrogen to 

 phosphoric acid. 



(5) The ratio of nitrogen, phosphoric acid and potash found in 

 high-grade fertilizers approximates much more closely the ratio found 

 in plants than does the ratio existing in the low-grade class. 



relation of selling price to commercial valuation. 



In the table below, we give the average actual selling price and the 

 average commercial valuation in the case of each class of fertilizers, 

 and also the excess of selling price over the commercial valuation. 

 Since the commercial valuation represents the average retail price of 

 the separate, unmixed materials contained in one ton of fertilizer at 

 the seaboard, the excess of selling price above commercial valua- 

 tion represents the cost of mixing, freight, profits and cost of business. 



In making the commercial valuations, the prices given in Bulletin 

 390 on page 492 are used, except that the available phosphoric acid 

 is valued at 4| cents a pound and the potash at 4| cents. 



