1180 EARLE V. HARDENBURG 



The percentages shown in table 22 indicate that on Long Island, nitrate 

 of soda and tankage are used almost universally as the sources of nitrogen 

 in home-mixed fertilizers. As is typical of coast regions, much fish scrap 

 also is used for its nitrogen content. Acid phosphate is the principal 

 source of phosphoric acid, altho ten per cent of the growers who mix their 

 own fertilizers on Long Island use bone meal, and an equal number use 

 raw rock phosphate, for the phosphoric acid supply. Of the potash supply 

 95 per cent comes from muriate of potash, and the remaining 5 per cent 

 comes in the sulfate form. 



In Steuben County, nitrate of soda and dried blood used together was 

 the main source of nitrogen, no tankage being used by the five per cent of 

 growers who mixed their own fertilizer. Phosphoric acid was obtained by 

 eighty-four per cent of these growers from acid phosphate, and five per cent 

 obtained it from bone meal. More sulfate of potash was used in this 

 region than in any of the other regions surveyed, altho 62 per cent of all 

 the potash was obtained in the muriate form. 



One-tenth of the growers visited in Monroe County mix their own 

 fertilizer. About an equal number of these growers obtained their nitro- 

 gen supply from dried blood and from tankage. A few used nitrate of 

 soda. All of these growers obtained their phosphoric acid from acid 

 phosphate. Muriate of potash was used by eighty-seven per cent of the 

 growers, v/hile thirteen per cent used the sulfate form for potash. 



Only one per cent of the growers in Franklin and Clinton Counties 

 practiced home mixing. These men used only nitrate of soda for nitrogen 

 and muriate of potash for potash. Acid phosphate was the principal 

 source of phosphoric acid, altho a little bone meal was used. 



Summarizing for the four regions, it is seen that nitrate of soda is the 

 commonest source of nitrogen. Generally, however, there is a tendency 

 to mix nitrate of soda with either dried blood or tankage to furnish nitrogen 

 in both a quickly and a slowly available form. Acid phosphate and 

 muriate of potash are the principal sources of phosphoric acid and potash, 

 respectively. 



Quantity and value of fertilizer 



The optimum amount of fertilizer for any crop necessarily depends 

 on three principal factors: the available supply of plant food in the soil, 

 the feeding requirements of the crop, and the net return per unit invested 

 in fertilizer. Of these, the first two are usually measured by the yield 

 per acre, regardless of cost, while the last is too often neglected. Macoun 

 (1905) has shown, by a large number of analyses, that a 200-bushel yield 

 of potatoes (exclusive of the tops) removes an average of 40 pounds of 

 nitrogen, 20 pounds of phosphoric acid, and 70 pounds of potash, per acre 

 of soil. This is about the same amount of nitrogen and phosphoric acid, 

 but twice as much potash, as is removed by comparable yields of wheat 

 and corn. 



