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ARS Home » Southeast Area » Auburn, Alabama » Soil Dynamics Research » Research » Publications at this Location » Publication #277335
Title: Estimating the economic optimal rate of nitrogen fertilizer: a battle of functional form

Author
item Duzy, Leah
item Balkcom, Kipling

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 11/2/2011
Publication Date: 5/1/2012
Citation: Duzy, L.M., Balkcom, K.S. 2012. Estimating the economic optimal rate of nitrogen fertilizer: a battle of functional form. In: Boyd, S., et al., editors. Proceedings of the National Cotton Council Beltwide Cotton Conference, January 2-6, 2012, Orlando, Florida. p. 445-450.

Interpretive Summary: Agricultural producers make fertilizer decisions based on recommendations from extension personnel and/or consultants established by the best available data; however, optimal nitrogen (N) recommendations can vary depending on the estimation of the crop response to N fertilizer. Applying too much or too little N fertilizer can negatively influence producer profits, as well as environmental conditions. The objective of this research is to evaluate cotton response to N fertilizer for cotton and compare the economically optimal rates of N fertilizer. The overall conclusion, when analyzed by year, is estimated crop response to N fertilizer depends on year. For 2006, 2007, and 2008, the crop response to N fertilizer was best described by as square root, linear, and quadratic, respectively. In the 2008, the difference in the expected revenue above N costs between the maximum yield and the economic optimal yield was approximately $1 per acre, demonstrating that, for this data, in 2008, there was little difference between the maximum and the economic optimal yield.

Technical Abstract: Agricultural producers make fertilizer decisions based on recommendations from extension personnel and/or consultants established by the best available data; however, optimal nitrogen (N) recommendations can vary depending on the functional form used to estimate yield response functions. Applying too much or too little N fertilizer can negatively influence producer profits, as well as environmental conditions. The objective of this research is to evaluate different crop response models for cotton and compare the resulting economically optimal rates of N fertilizer. The overall conclusion, when analyzed by year, is that the appropriate functional form differs by year. For 2006, 2007, and 2008, the preferred functional forms were the square root, linear, and quadratic functional forms, respectively. In the 2008, the difference in the expected revenue above N costs between the asymptotic maximum and the economic optimal was approximately $1 per acre, demonstrating that, for this data, in 2008, there was little difference between the asymptotic maximum and the economic optimal.