The Bulletin. 



31 



Continued. 



YEARS IN FIELDS A, B AND 0. 



there is a uniform increase or decrease in the natural fertility between check plats, and a cor- 

 rected check was figured on this basis for each treated plat between checks. 



respectively, on Fields B and C, the largest profits were obtained from 

 the plats receiving fertilizer application containing twice the normal 

 quantity of nitrogen in the mixture, or 20 pounds of nitrogen per acre. 



Taking the seven years' experiments together, the average results 

 show an average increased yield over unfertilized plats of 737 pounds 

 of seed cotton, worth $30.11 for the fertilizer application containing 

 one-half the normal quantity of nitrogen (N^/o P K), (this equals 5 

 pounds nitrogen per acre), and 777.5 pounds, worlJa $28.47 for the 

 fertilizer application containing twice the normal quantity of nitrogen 

 (N2 P ^)- (This equals 20 pounds nitrogen per acre.) 



These results indicate, as do those in the preceding table, that nitro- 

 gen is not the most important or controlling constituent for the pro- 

 duction of cotton on this soil. 



