New York Agricultural Experiment Station. 397 



ous other special names. For some years these fertiUzers have 

 been popular with many farmers. As they contain no nitrogen, 

 they can be sold at prices that look cheap in comparison with the 

 prices of complete fertilizers. Many farmers consider cost only 

 and not composition in purchasing fertilizers. 



In 1902 we found in the market 58 different brands of this kind 

 of fertilizer. In average composition, these mixtures contained 

 II. 10 per ct. of available phosphoric acid and 4 per ct. of potash. 

 The selling price varied from $13.50 tO' $26 a ton, averaging 

 $19.17, while the commercial valuation varied from $4.60 to 

 $19.01, averaging $14.50. The average selling price exceeded 

 the average commercial valuation $4.67 a ton; in one case, the 

 difference was as great as $13.40. The cost of one pound of 

 available phosphoric acid varied from 4.3 cents to 19.5 cents and 

 averaged 6.6 cents. The cost of one pound of potash varied 

 from 3.7 cents to 16.5 cents and averaged 5.6 cents. 



From the foregoing data, we conclude: 



(i) That, in cost of plant- food, the lowest prices compared 

 favorably with the lowest prices found in complete high-grade 

 mixtures, while the highest prices were greatly in excess even of 

 the highest prices found in low-grade complete fertilizers. The 

 average prices were somewhat above those found in medium 

 high-grade complete fertilizers. 



(2) That the selling prices of mixtures of acid phosphate and 

 potash salts are subject to much wider variations than in com- 

 plete goods and average dearer than complete high-grade goods. 



COST OF PLANT-FOOD IN THE FORM OF ACID PHOSPHATE. 



Most of the phosphoric acid in the market is dissolved rock, 

 no matter under what name sold, especially if it contains no 

 guaranteed nitrogen. Real dissolved bone and bone-black are 

 comparatively rare. In 1902 we collected 34 different brands of 

 goods contaming only phosphoric acid compounds. In these 

 brands, the available phosphoric acid varied from 11.42 to 17.10 

 per ct., averaging 14.56 per ct. The selling price varied from 

 $13 to $25 a ton and averaged $14.95. The commercial valua- 

 tion varied from $11.42 to $17.10 and averaged $14.56 a ton. 

 In one case, the selling price exceeded the commercial valuation 

 $13.58. The cost of one pound of available phosphoric acid 



