50 Report of the Department of Agronomy of the 



but derived principally from sandy clays and shales, and resembling 

 very closely the hill-land soils of southern New York. At Strongs- 

 ville, Ohio, the experiments are located on a level clay loam soil 

 very similar in formation and general characteristics to the lake 

 front lands of New York State. At both places in Ohio the entire 

 experiments are carried out each year on each of five different fields, 

 and in Pennsylvania on four different fields. 



Results in accord with these Ohio and Pennsylvania experiments 

 as to the comparative value of nitrogen, phosphorus and potassium 

 on general farm crops have been obtained at a number of other state 

 experiment stations in eastern United States. No important experi- 

 ments conducted on extensive soil types in our eastern states and with 

 general farm crops have brought out any radically different results. 

 ' The term " general farm crops " as used above will include many 

 others not included in the Ohio and Pennsylvania experiments. 

 It will include probably all grain and forage crops, and even alfalfa 

 and potatoes. 



Fertilizing potatoes.— A study of all available data will snow that 

 potatoes, which are commonly supposed to require a fertilizer high 

 in potassium, will, on the contrary, give greater returns from a phos- 

 phorus fertilizer than from either nitrogen or potassium. In fact, 

 potassium is more often used on potatoes at a dead loss. As evidence 

 on this point we have the results of fertilizer tests with potato- 

 growing on Long Island, conducted by this Station on four different 

 farms for three years each. A comparison was made between four 

 different fertilizer mixtures all containing the same amount of nitro- 

 gen and phosphorus, but varying in potassium from nothing to 

 8.3 per ct. (10 per ct. K 2 0). All four were used at the rate of 

 pounds per acre. They varied in composition as follows: 



N. 



No. 

 No. 

 No. 



No. 



1. 

 2. 

 3. 

 4. 



4 

 4 

 4 

 4 



P. 

 3.5 

 3.5 

 3.5 

 3.5 



K 







2.9 



5.8 



8.3 J 



> or 



N. P 2 Oo 



4 



4 

 4 

 4 



8 

 8 

 8 

 8 



K2O. 

 

 3.5 



7 

 10 



The results of this test are given in the following table: 



Table IV.— Comparison of Varying Amounts of Potassium in Fertilizing 

 Potatoes on Long Island (1898-1899-1900). 



Number of Plats Averaged. 



S 



X 



s 



8 

 8 



Fertilizer mixture 



applied at the rate 



of 1,000 lbs. per acre, 



No fertilizer 



4-8-0 



4-8-3.5.... 



4-8-7 



4-8-10 



Average yield per 

 acre for 3 years 



(1898-1900) on four 

 different farms. 



89 bushels 

 123 bushels 



127 bushels 

 129 bushels 



128 bushels 



