Cover crops and no-tillage practices can promote the sustainability of soil resources. A field study conducted in 2002 to 2004 at Stoneville, MS, on a Dundee silt loam, evaluated the effects of cover crops (rye, hairy vetch, and none) and tillage [conventional (CT) and no-tillage (NT)], on soil chemical properties and soil enzyme activity (fluorescein diacetate hydrolysis, FDA activity). Cover crops were killed before soybean planting, incorporated into soils in CT plots, and left on soil surface in NT plots. Soil (0 to 5 cm depth) was sampled at planting, and three times following soybean planting. NT soils especially under cover crop management maintained the highest soil moisture content and the highest organic carbon content. Soils managed under a hairy vetch cover crop maintained two- to four-fold greater soil nitrate and higher electrical conductivity compared to no cover crop especially under CT. The greatest FDA activity was associated with NT plots, especially under cover crop management associated with greater moisture availability and higher organic matter content. Results from these studies indicate that cover crops especially under NT systems improve the sustainability and quality of soil under Mississippi Delta conditions.