Efficient soil water management is crucial for sustaining agriculture in arid and semi-arid regions. Cover cropping and compost application are promoted for agricultural sustainability in dry areas, but how they affect soil water storage or loss has not been studied well. This study evaluated the effects of compost application and cover cropping on soil water content (SWC), evapotranspiration (ET), and crop water productivity (CWP) in sorghum (Sorghum bicolor (L.) Moench) production system of the semi-arid Southern High Plains of USA. Treatments included two cover crops- peas (Pisum sativum L.) and a six-species mixture (SSM) comprising peas, oats (Avena sativa L.), canola (Brassica napus L.), barley (Hordeum vulgare L.), hairy vetch (Vicia villosa Roth), and forage radish (Raphanus sativus L.)-as well as no cover crop (NCC) fallow as a control, and two levels of compost application (yes and no). Two years of field observations and simulations using the Root Zone Water Quality Model 2 (RZWQM2) showed that SSM initially depleted soil water among cover crops due to the higher water demand, but it conserved more water during the sorghum harvest. Compost addition increased SWC and CWP compared to no-compost, increasing sorghum yields by 22-29%. The RZWQM2 model could effectively replicate field observations, with root mean square error (RMSE) ranging from 0.02 to 0.05 cm(3) cm(-)(3) for soil water and 1.12-3.22 degrees C for soil temperature. Therefore, adding compost to cover crop-integrated rotations could enhance soil water retention, reduce ET, and increase sorghum productivity, improving water use efficiency in water-limited environments.