Long-Term Effects of Different Cover Crops, Tillages, and Nitrogen Fertilization Rates on Soil Properties Under Continuous Cotton System of West Tennessee.

Conservation practices including no-tillage, are important components of sustainable row-crop production systems management. The long-term potential of no-tillage systems for improving soil quality can be enhanced through integration with best management practices such as the use of winter cover crops. The long-term effects of no-tillage and winter cover crops on soil properties may differ drastically from a region to another. For this study we sampled soils from a long-term tillage (till and no-till), cover crop (crimson clover-Trifolium incarnatum L., hairy vetch-Vicia villosaL. and winter wheat-Triticum aestivum L., and winter fallow), and nitrogen fertilization rates (0, 34, 67 and 101 kg N ha^-1) experiment. This study was initiated in 1981 under continuous cotton (Gossypium hirsutumL.)on a silt loam soil in west Tennessee. Samples were collected from 0-15 cm depth from each treatment and analyzed for dissolved organic carbon (DOC), wet aggregate stability (WAS), total organic carbon (TOC), permanganate oxidizable carbon (POxC), and total nitrogen (TN). Results showed higher TOC, WAS and TN under no-till compared to tillage, and under hairy vetch compared to a wheat cover crop. DOC was not significantly different among treatments. Laboratory analyses are currently underway, and the results will be presented at the conference.