Nitrogen applications on cotton in the Mississippi Delta

Efficient resource use is economically sound and socially desirable. One of the primary nutrients used by cotton producers is nitrogen. Management decisions regarding nitrogen levels and methods of application integrate sound production practices with proven economic principles to optimize efficient allocation of resources. Essential to the decision-making process is knowledge of the manner in which the cotton plant responds to nitrogen so that costs and revenues may be applied and economic alternatives analyzed. The risk associated with uncertain weather patterns may be incorporated into the mathematical calculations in determining N levels which will optimize expected the net returns from alternative nitrogen procedures.;In this study data generated by the GOSSYM-COMAX simulator indicates a linear response with a yield plateau or LRP function. For each of three weather years and under both dryland and irrigated scenarios the LRP type was evident. Tables were created to display the alternative procedures and treatments with the associated predicted net returns under certainty and expected net returns under uncertainty for each weather year with and without irrigation.;The dryland results indicate that optimal levels of N under conditions of certainty and uncertainty generate higher yields and (expected) net returns with the greater concentration of N from mid-season UAN. Applications of late-season urea improve both net returns for all three weather patterns and expected net returns. The economically optimal treatment combines 25 pounds of N as AA with 125 pounds N as UAN and 10 pounds N as urea.;Under irrigated conditions the results indicate that nitrogen concentrated in the preplant AA form generates the highest net returns and expected net revenues. Late-season urea improves net returns for the normal and cold weather years but not the hot year. The optimal procedure suggests that 100 pounds of N as AA be combined with 75 pounds as UAN and 10 pounds as urea. Irrigation capabilities enable proper water management to increase production and economic efficiency of nitrogen use.