38 THE POTATO 



the average gain from the use of a full application 

 of fertilizers was eighty bushels per acre. In Long 

 Island, N. Y., a fertilizer mixture containing 4 per 

 cent, nitrogen, 8 per cent, available phosphoric acid, 

 and 10 per cent, potash has proven satisfadlory. It 

 is used in amounts varying from 500 pounds to 2,000 

 pounds per acre, and in many cases more potash is ap- 

 plied than is profitable. The use of i ,000 pounds of 

 this fertilizer has given the greatest profit. Where 

 1,500 pounds or 2,000 pounds were used the cost of the 

 fertilizer was more than the market value of the in- 

 creased yield of potatoes. For some 3'ears I have used a 

 mixture of 100 pounds sulphate of ammonia, 400 to 600 

 pounds acid phosphate (16 to 17 per cent, available), 

 and 100 pounds muriate of potash with eight to ten 

 tons of partially rotted manure per acre on a medium 

 loam soil. At New Hampshire Experiment Station' 

 300 pounds muriate of potash per acre gave the best 

 results when compared with none, 150 pounds, and 450 

 pounds per acre. 



The above mixtures merely show quantities used by 

 certain individuals ; each farmer must work out a mix- 

 ture suited to his needs. There are other conditions 

 than the application of fertilizers. As Dr. W. H. Jordan' 

 pithily puts it: "It is clearly evident that a large 

 supply of plant-food does not necessarily insure a 

 satisfactory crop. Other conditions which largely per- 

 tain to culture — such as texture, humus, and water- 

 supply — exercise a controlling influence, and when 

 these conditions are unfavorable their effedl is not over- 

 come by heavy applications of fertilizer. ' ' 



' N. H. Bui. Ill, p. 115. « (N. Y.) Geueva Bui. iSy, p. 215. 



