36 The Bulletin. 



Effect of Varying Quantities of Fertilizer on Yields. 



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

 creasing and decreasing the normal (IST P K equals 400 pounds of a 

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

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

 The applications were at the rate of 200 pounds per acre (^ N P K) ; 

 400 pounds per acre (N P K) ; 600 pounds per acre (11/2 N P K) ; 800 

 pounds per acre (2 IST P K) ; and 1,000 pounds per acre (21/0 1^ P K) ; 

 The results on several fields and the averages of the two fields are quite 

 uniform in showing increased yields and increased profits for the several 

 increases in the amounts of fertilizer, 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 profitable fertilization for cotton on 

 this soil has not been reached, and that more than 1,000 pounds per acre 

 would give remunerative returns. It should be remembered, too, in this 

 connection, that the composition of this mixture is not especially adapted 

 to this soil, as shown by results in previous tables. A larger per cent of 

 nitrogen would certainly have increased the yields and very probably 

 the net profit. 



In addition to larger profits from heavy fertilization of the right kind, 

 the land is in all probability improving in productiveness and value. 

 Results on these plats and fields in after years will be most valuable in 

 throwing light on this most important phase of the proper fertilization 

 for immediate returns and for the permanent improvement of the soil. 

 This latter phase of farm practice is not given the thought and consid- 

 eration it should receive bv most farmers. 



