The Bulletin 



67 



Nitrogen and Phosphoric acid, IST P (Plats 1 and 1). Nitrogen 

 and phosphoric acid alone gave increased yields over the unfertilized 

 plats for all eight years on the plats in the two fields, the average annual 

 increase for five years in Field A being 326.1 pounds seed cotton per 

 acre, and for the three years in Field B being 504.1 pounds seed cotton, 

 or an average annual increase for eight years in the two fields of 415.1 

 pounds per acre, worth $15.14 over the cost of the fertilizer applied. 



Nitrogen and Potash, N K (Plats 2 and 2). From an application 

 of nitrogen and potash combined there were small average increased 



Fig. VIII. Cotton on plats at Central Farm. Plat 12, unfertilized (O) in center; Plat 11, 

 high phojphatic fertilization with normal amounts of nitrogen and potash (NP3K) 

 on right; and Plat 13, low potassic fertilization with normal amounts of phosphoric 

 acid and nitrogen (NPKy2) on left. NP3K plat yielded more than nine times and 

 NPK% more than seven times as much seed cotton as the unfertilized (O) plat. 



yields on the plats of the two fields, the average for the five years being 

 166.2 pounds seed cotton for Field A, and 173.6 pounds as an average of 3 

 years for Field B, or an average annual increase for both fields of 169.9 

 pounds of seed cotton per acre, worth $4.84 over the cost of fertilizer used. 



Phosphoric Acid and Potash, P K (Plats 3 and 3). Phosphoric 

 acid and potash combined gave increased yields on all the plats in the 

 two fields, the average annual increase for five years in Field A being 

 297.6 pounds and for three years in Field B 631.2 pounds; or an average 

 for the eight years in the two fields of 464.4 pounds, worth $19.17 

 over cost of fertilizer. 



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

 These three materials combined in a complete fertilizer gave increased 

 yields in all the tests on all the plats in tAvo fields, the average annual 

 increase for five years in Field A being 387.5 pounds of seed cotton per 



