James E. Hanks1, Steven W. Martin2, D.K. Fisher3, and J. Ray Williford3. (1) USDA Agricultural Research Service, 141 Experiment Station Road, Stoneville, MS 38776, (2) Delta Research and Extension Center, PO Box 69, Stoneville, MS 38776, (3) USDA-ARS APTRU, 141 Experiment Station Road, P.O. Box 36, Stoneville, MS 38776
Field studies were conducted at Stoneville, MS to investigate the effects of reducing inputs with conservation management practices in cotton production in a typical Mississippi Delta field with highly variable soils. Significant interest has developed to find ways of reducing production inputs without major reductions in yield that also minimize the environmental impact to the surrounding area. The objective of this study was to investigate the impact of varying soils on cotton produced with minimum-till and no-till conservation management practices. The study compared minimum-tillage practices with no-till for continuous cotton production and for cotton production in an alternate year rotation. Soils consisted of Bosket and Dundee very fine sandy loam; Dundee and Sharkey silty clay loam; and Sharkey and Tunica clay. Soil electrical conductivity (EC) which indicates increasing clay content as EC values increase was measured with a Veris Technologies 3100 Soil Mapping System. AGIS geographical information system (GIS) software was used for all geo-referenced processing and analyses. Furrow irrigation was used to supply supplemental water as needed. Average yields were 1068, 1127, 1138, and 1143 lint pounds per acre, respectively, for the no-till corn/cotton rotation, minimum-till continuous, no-till continuous and minimum-till corn/cotton rotation treatments. The average EC for the treatments indicated the highest productivity should be from the no-till continuous plots and the lowest from the corn/minimum-till plots. Therefore, linear regression analyses were used to develop projected yields based on soil EC and yield from previous studies. Projected yields based on soil EC were normalized to allow comparison of all treatments to yield of the minimum-till continuous cotton. Results of these comparisons indicated that when produced on soil with similar EC the no-till continuous treatment produced 10 percent less than the minimum-till continuous, no-till corn/cotton rotation produced 2 percent less than the minimum-till continuous, and the minimum-till corn/cotton rotation produced 9 percent more than the minimum-till continuous. Regardless of tillage method, corn/cotton rotation yielded 9 percent more than continuous cotton production. These results indicate reduction in the tillage input can be achieved with minimal change in cotton yield. Significant change in production practices would require varying degrees of equipment changes; therefore, a case-by-case analysis of the environmental and economic factors will need to be considered carefully before making the change to a conservation management production system.