48 



The Bulletin. 



Table V— 

 AVERAGE RESULTS FOR 5 YEARS 



*Soil better than other plats; yields too liigh. fThree times normal quantity of fertilizer 

 apphed this year, 3(NPK). JThis average is for years 1904, 1905, 1906, 1907 and 1909. 



Note.- — The check for plat 8, field A, has been obtained from plats 4 and 11; that for 

 plat 102, field B from plats 52 and 142, and for plats "3, 83, 93 and 103, field B, from plats 5» 

 and 143. It has been assumed that there is a uniform increase or decrease in the natural fertil- 

 ity between check plats, and a corrected check was figured on this basis for each treated plat be- 

 tween checks. 



EFFECT OF VARYING QUANTITIES OF FERTILIZER ON YIELDS. 



The experiments in Table V were planned to show the effect of 

 increasing and decreasing the normal (I^ P K equals 400 pounds of a 

 fertilizer mixture containing 7 per cent phosphoric acid, 2^/0 per cent 

 potash and 21/2 per cent nitrogen) fertilizer application on the yields. 

 The applications were at the rate of 200 pounds per acre (1/2 N P 

 K) ; 400 pounds per acre, N P K; 600 pounds per acre (II/2 ^ P 

 K) ; 800 pounds per acre (2 Is^ P K) ; 1,000 pounds per acre 

 (21/2 N P K)- The results on the several fields and the averages 

 of the three fields are quite uniform in showing increased yields and 

 increased profits for the several increases in the amounts of ferti- 

 lizer, the quantity of fertilizer per acre varying from 200 to 1,000 

 pounds. The largest yields, as well as the greatest profit, were 

 obtained from the 1,000-pound application. It is possible that the 

 limit of the most profitake fertilization for cotton on this soil has 



