Abstract
Cover crops can increase crop water productivity (CWP) and succeeding crop yield. However, cover crops adoption in the Southern High Plains of USA is slow due to limited water available for crop production. This study evaluated the effects of winter cover crops on soil water dynamics, corn silage yield and nutritive values, and corn silage CWP in a semi-arid irrigated condition. Three winter cover crop mixtures: grasses + brassicas + legumes (GBL), grasses + brassicas (GB), grasses + legumes (GL), and control or no cover crop (NCC) were evaluated for soil water storage, cover crop biomass, corn silage yield, nutritive values, and crop evapotranspiration (ET), and the cover crop-corn silage system water productivity (SWP) under a no-till irrigated corn silage production system. All cover crop treatments reduced soil water storage before their termination in both years. However, water storage was higher for all cover crop treatments than for NCC during corn growth. Average CWP for corn was improved by 14-29% with cover crop mixtures over the NCC. Corn silage yield among cover crop treatments was 9-26% higher than NCC. Nutritive value components of cover crops such as non-fat carbohydrates, relative forage quality, and Ca and Mg were higher in the GBL and GL mixtures than the GB in one of the two years. This study demonstrated increased corn silage yield and water productivity with cover cropping. Cover crops mixtures with legumes could offer a high-quality alternative forage for crop-cattle integrated systems, including dairy producers in the Southern High Plains region.