Economic analysis of residue management system in cotton

Cotton production generates the highest amount of farm-gate income among crop enterprises in Georgia. Economic viability and sustainability of cotton production in the Georgia Piedmont region are questionable due to continuous deterioration of soil quality with conventional tillage and chemical fertilizer application. Residue management systems comprising winter cover crops were analyzed as an alternative to the existing system comprising conventional tillage and chemical fertilizer using yield benefit, net revenue, and sustainability criteria.; Residue management systems improve soil structure due to increased soil organic matter. To find the effect of organic matter-induced yield efficiency, cotton yield was simulated at four levels of organic matter and ten levels of nitrogen using Erosion Productivity Impact Calculator (EPIC). Nitrogen was chosen because organic matter plays an important role in the cycling of nitrogen in soil. Nitrogen is also the most applied plant nutrient in cotton cultivation. The joint hypothesis test indicated that the Mitscherlich-Baule (MB) production function provides the best fit of the relationship between yield and nitrogen at different levels of organic matter. Applied nitrogen can be reduced when there is more organic matter in the soil to get the same yield compared to when the percentage of organic matter is low. The rate of yield response to nitrogen differed under different management systems for a given organic matter level.; A profitability index was calculated based on the organic matter development function. An organic matter accumulation function was simulated for four management systems each with a winter cover crop and a combination of either poultry litter or chemical fertilizer as a nutrient source and either conventional tillage or no-till as a cultivation method. Organic matter accumulation was found to be the highest in the system with poultry litter and no-till and lowest in the system with conventional tillage and chemical fertilizer.; Sustainability of systems was measured by using a total factor productivity index and a profitability index. The cost of maintaining organic matter at the existing level was calculated for each system. The system with no-till and poultry litter required the fewest years of cover crop planting compared to other management systems in order to maintain the existing level of organic matter. The role of alternative management practices in sustaining crop yield and net return has proven them profitable and sustainable.