24 The Bulletin. 



Effect of Yakting Quantities of Nitkogen. 



These tests (Table II) were planned to determine tlie effect on the 

 yield of cotton of varying quantities of nitrogen, leaving the phosphoric 

 acid and potash constant. On one j)lat the nitrogen was reduced to 

 one-half of the normal quantity, making the applicati:n 5 pounds of 

 nitrogen per acre or practically 1^ per cent in the ferUl'zer mixture. 

 On two of the plats it Avas increased by 2 and 3 times the riormal quan- 

 tity (10 pounds per acre), making the application 20 and 30 pounds 

 per acre respectively, or on basis of the fertilizer mixture 5 and 7^ 

 per cent. The average results for both fields show the largest yield and 

 profit from the fertilizer application containing three times normal or 

 the largest quantity of nitrogen in the several mixtures. The three 

 times normal application which represents a fertilizer analyzing 

 7 — 7^4 — '^/^ gave an average annual increase of 784 pounds of seed 

 cotton, a profit of $26.45 over the cost of fertilizer. With the exception 

 of the two and a half times normal application this represents the 

 largest profit. 



These results indicate as they do those with corn, that nitrogen is one 

 of the controlling constituents, if not the most important one for crop 

 production on this soil. 



