Tillage and Irrigation Management of Cotton in a Corn/Cotton Rotation

Authors: Hanks, James; Fisher, Daniel

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/12/2010
Publication Date: 1/12/2010
Citation: Hanks, J.E., Fisher, D.K. 2010. Tillage and Irrigation Management of Cotton in a Corn/Cotton Rotation. National Cotton Council Beltwide Cotton Conference. Vol. 1, pp. 1-4.

Interpretive Summary: Cotton cropping systems involving an annual corn-cotton rotation are becoming commonplace in the southeastern United States. Incorporation of conservation-tillage practices, to reduce input costs and address environmental concerns, and irrigation, to supplement rainfall, are increasing. A research study was undertaken to evaluate the yield of cotton in a corn-cotton rotation under varying tillage and irrigation practices. The objectives were to examine cotton yield under four irrigation/tillage treatments, ibncluding conventional and minimum tillage and irrigated and non-irrigated conditions. The five-year study showed that, in general, yields were higher under irrigated conditions, but these results varied depending on the season’s rainfall conditions. Average yields were slightly higher under conventional-tillage conditions, but differences between the conventional- and minimum-tillage treatments amounted to only 6%. While minimum-tillage production may not have increased yields, the difference in yields was minimal. This could affect profitability by decreasing input labor and cost without a significant decrease in yield. The study also pointed to the importance of taking soil type into account when analyzing treatment results. Highly variable soils, and resulting agronomic differences independent of imposed treatments, could significantly affect treatment outcomes, resulting in misleading interpretations.

Technical Abstract: A research study was undertaken to evaluate the yield of cotton in a corn-cotton rotation under two tillage treatments, conventional and minimum/conservation, and two irrigation treatments, irrigated and non-irrigated. Crops were grown under four treatments, irrigated-conventional tillage, irrigated-minimum tillage, nonirrigated-conventional tillage, and nonirrigated-minimum tillage, with each treatment subdivided into three plots. Maps of soil electrical-conductivity were developed using Veris soil-mapping equipment to quantify soil variability across the field. Soils were shown to be highly variable within each treatment and across the four treatments. In general, yields were higher under irrigated conditions, but these results varied depending on the season’s rainfall conditions. Average yields were slightly higher under conventional-tillage conditions, but differences between the conventional- and minimum-tillage treatments amounted to only 6%. While minimum-tillage production may not have increased yields, the difference in yields was minimal, which could affect profitability by decreasing input labor and cost without a significant decrease in yield. Results also highlighted the importance of taking soil type into account when analyzing treatment results. Yields were highly correlated with Veris measurements, and agronomic differences independent of imposed treatments made interpretation of treatment results difficult. Disregarding soil variability significantly affected the interpretation of treatment outcomes, resulting in misleading interpretations. By taking soil variability into account, interpretation of treatment results led to differing conclusions. Soil variability is an important factor which must be taken into consideration when researchers examine experimental results, and when producers put recommendations into practice.