Cover Crop Influence on Stored Soil Water Availability to Subsequent Crops.

With the increasing interest toward organic crop production, cover crops are gaining more importance as a sustainable practice to improve cropping system productivity and diversity, weed management, and soil health. However, producers are concerned that cover crops may reduce the amount of moisture in the soil that would be available to subsequent cash crops. The objective of this study was to evaluate the common cover crops in SC for soil moisture retention and biomass production. We evaluated seven cover crop treatments including grasses, legumes, and brassicas as single species or in mixtures, and compared them with two controls, a weed-free fallow and a weedy fallow, in an on-farm trial. Soil moisture content was measured at 10, 20, 30, 40, 60, and 100 cm depths at approximately biweekly intervals during cover crop season and at one month after termination (MAT). Biomass was measured at monthly intervals during the cover crop season. All cover crop treatments retained more or equal amounts of soil moisture compared to controls during the growing season and at 1 MAT. Rye, crimson clover, turnip+clover, oat+radish, and a mixture of five (Austrian winter pea+rye+ clover+hairy vetch+oat) retained maximum amount of soil moisture. Rye and the mixture of five were the best ‘ground covers’ in terms of stand count, and produced largest amount of biomass throughout the growing season. Crimson clover and turnip+clover had the lowest stand counts and least biomass production. Our results suggest , among the cover crops treatments evaluated in this study, rye and the mixture of five are the best in terms of saving soil moisture for the next cash crop, biomass production, and ground coverage. In addition, our results do not support the perception that cover crops, when compared to a fallow, will deplete soil moisture and cause water stress for the next cash crop.