Soil–plant–water relations and water footprint of cover crop–based no‐till cotton and sorghum systems in a humid region

Tillage and cover cropping are known to affect soil water dynamics and crop evapotranspiration (ET), and consequently, water footprint (WF) of crop production and economic return. In this study, two tillage practices (conventional tillage [CT] and no‐tillage [NT]) and cover crop (CC) treatments (Austrian winter pea [ Pisum sativum ] CC and no‐CC [NC]) were investigated to quantify soil water balance, ET, and WF of yield and revenue for cotton ( Gossypium hirsutum ) and sorghum ( Sorghum bicolor ) production. Soil volumetric water content was measured from 0‐ to 120‐cm depth from May to October in 2020 and 2021. Runoff, deep percolation, and ET were modeled using the root zone water quality model (RZWQM2), and WF was determined as m 3 of water consumed per kg of yield or unit revenue. The RZWQM2 performance was acceptable, validated by low residual errors. Pooled across years, CT treatments depleted soil water storage by 9% and 7% over the season in cotton and sorghum, respectively, which was 6% and 7% for NT. No‐till reduced the runoff by 31% over CT when averaged across years and cash crops. The NTCC (no‐tillage, cover crop) minimized ET, compared to NTNC (no‐tillage, no cover crop) and CT treatments, particularly in sorghum. Tillage increased the WF of yield and revenue for cotton by 7% and 6% over NT treatments, respectively. In sorghum, neither tillage nor cover cropping altered the WF outcomes. Overall, cover cropping and conservation tillage could be used to complement each other to minimize the WF of cotton and sorghum production in the humid Lower Mississippi River Basin.