November, 1925] fertilizer inspection, 1925 5 



highest $71.00 per ton. The consumer can only protect 

 himself against such unjustifiable differences in price by 

 figuring the commercial value of a fertilizer for himself 

 before he agrees to purchase it. 



A summary of the prices at which some of the different 

 fertilizer materials were sold during the past year will 

 illustrate how a comparison of the relative value of different 

 grades may be computed. 



Four brands of 16 per cent acid phosphate were offered 

 at an average price of $27.75 per ton. One ton of 16 per 

 cent acid phosphate contains 320 pounds of phosphoric acid. 

 The cost per pound is $0.0867 and per unit $1,734. 



The average cost of muriate of potash containing 50 per 

 cent of water soluble potash was $52.50 per ton. One ton 

 contains 1000 pounds of potash. The cost per pound is 

 $0.0525 and per unit $1.05. 



The cost of nitrate of soda containing 15 per cent nitro- 

 gen was $78.00 per ton. One ton contains 300 pounds of 

 nitrogen. The cost per pound is $0.26 and per unit $5.20. 

 The average cost of tankage was $56.33 per ton. It con- 

 tained an average of 6.65 per cent nitrogen and 5.25 per 

 cent available phosphoric acid. The value of 5.25 units 

 of available phosphoric acid at $1.73 per unit is $9.08. The 

 nitrogen cost $56.33 less $9.08 or $47.25 for 6.65 units. The 

 cost per unit of nitrogen is $7.11 and per pound $0,355. 

 Assuming the complete fertilizers contain equal amounts 

 of organic and inorganic nitrogen the cost of nitrogen is 

 the average of $0.26 for the inorganic form and $0,355 

 for the organic form or $0,307 per pound and $6.14 per 

 unit. 



Using the above values for nitrogen, phosphoric acid and 

 potash in the unmixed materials the calculated value per 

 ton of the different grades of mixed fertilizers as compared 

 with the retail price per ton is shown in Table IL Only 

 those grades are included on which two or more retail 

 quotations were available. 



