33 



terials. On the other hand, the present season (the fall of 1920) seems to 

 offer unusual opportunities to save on the fertilizer bill by the purchase of 

 unmixed materials, for the reason that the materials which make up the mixed 

 goods for the 1921 trade were bought on a high market and the curtailment 

 of European credits has caused a sharp decline in the price of many of the 

 crude stock materials which will have to be used in this country. These 

 products will no doubt be gradually absorbed by the fertilizer manufacturers, 

 which should result in more moderate prices for mixed goods another 

 season. 



It is not always good practice to buy mixed goods according to the trade 

 name alone, on accoimt of the large variety of formulas that are advocated 

 by the different manufacturers for the same crop. For instance, a study of 

 the tables of analysis for the season of 1920 shows that 36 different brands of 

 so-called potato fertilizers were sold in ^Massachusetts. These varied in 

 guaranteed composition so that 15 different grades were represented, as 

 follows : — ■ 



Grade 2-8-3, 11 brands. 



Grade 4-8-4, 9 brands. 



Grade 3-8-4,' 3 brands. 



Grade 2-8-2, 2 brands. 



The remaining grades had only one brand each, and varied in nitrogen from 

 2 to 5 per cent, in phosphoric acid from 6 to 10 per cent, and in potash from 

 1 to 7 per cent. 



An economical and intelligent selection of fertilizers can be made only after 

 a study of local conditions and of the fertilizer needs of the crops to be grown 

 on the various types of soil, and it should be remembered that every soil is 

 an individual problem. When it is ascertained what formula is needed it 

 should be purchased of the party who will furnish it for the least money, pro- 

 vided, of course, the purchaser has full confidence in the manufacturer. As 

 a rule, the prices for the same grade of goods put out by the large manufac- 

 turers do not vary to any considerable extent when figured on the same basis 

 of payment and tonnage. The same formula put out by different firms may, 

 however, vary more or less in its general make-up. Some brands may con- 

 tain a larger proportion of mineral nitrogen than do others, or possibly a 

 grade of organic nitrogen which in part may be of inferior quality, or the 

 phosphoric acid may be more available in one case than in another. These 

 points can usually be determined by a study of the annual fertilizer bulletins 

 from season to season. 



