20 The Bulletin. 



The experiments above were planned to test the effect on yield 

 of nitrogen (N), phosphoric acid (P), and potash (K) when ap- 

 plied singly; when two of the constituents were applied together, 

 as nitrogen and phosphoric acid (N P), nitrogen and potash (N K), 

 and phosphoric acid and potash (P K), and when all three of the 

 fertilizing constituents were applied to make a complete fertilizer 

 {Is P K). 



The results are shown in yields of hay in pounds or peas in 

 bushels per acre for the several years, average yields, average in- 

 creases over the unfertilized (O) plats, which represent the effect 

 of the fertilizer applications, the value of the increase, the cost 

 of the fertilizer, and the value of the increased yield over cost of 



fertilizer. 



EFFECT ON YIELDS OF HAY. 



Nitrogen, N (plats 1 and 1). From nitrogen alone in Field C 

 there were increased yields of hay in 1904 and 1905 and decreases 

 in 1906 and 1907 over the unfertilized plat (8), the average in- 

 crease being 475 pounds, while in 1908 in Field A the plat (1) 

 receiving nitrogen and the unfertilized plat (4) produced the same 

 yield. Plat 1 had had an application of nitrogen alone in corn and 

 cotton tests during the previous six years and plat 4 had had no 

 fertilizer during the same time. 



Phosphoric Acid, P (Plats 2 and 2). Phosphoric acid alone 

 produced increased yields in all of the five years on the plats in 

 both fields, the average for the first four years being 720 pounds of 

 hay, and for the fifth year in Field C 1,700 pounds, worth at $15 

 per ton i-espectively $4.20 and $11.55 over the cost of fertilizer. 



Potash, K (Plats 3 and 3). From potash alone in Field C the 

 yields increased in 1904, 1905, and 1907, and decreased in 1906, 

 the average annual increase being 340 pounds of hay. In Field A 

 there was no increase due to potash in 1908 and the fertilizer appli- 

 cation was a loss. 



Nitrogen and Phosphoric Acid, 'N P (Plats 4 and 5). Phosphoric 

 acid and nitrogen combined gave increased yields over the unferti- 

 lized plats in all five years oii the plats in both fields, the annual 

 average for the first four years in Field C being 460 pounds of hay 

 (less than for phosphoric acid alone, which was 720 pounds). For 

 the fifth year (1908) in Field A the increase was 2,200 pounds, or 

 100 pounds more than the phosphoric acid alone gave. 



Nitrogen and Potash, jST K (Plats 5 and 6). From the applica- 

 tion of nitrogen and potash combined the yields were increased in 

 three years and gave the same yield in one year in Field C, the aver- 

 age increase for the four years being 292 pounds of hay, the smallest 

 increase from any of the applications in the test. In Field A in 1908 

 there was a gain of 500 pounds of hay, due to potash and nitrogen. 



