Synergistic water quality and soil organic carbon sequestration benefits of winter cover crops

Authors: Zhang, Xuesong; WANG, Y - Orise Fellow; LEE, S - University Of Seoul; LIANG, K - University Of Maryland; ZHAO, K - The Ohio State University; McCarty, Gregory; Alfieri, Joseph; MOGLEN, G - University Of North Carolina; HIVELY, W - Us Geological Survey (USGS); MYERS, D - Stroud Water Research Center; OVIEDO-VARGAS, D - Stroud Water Research Center; NGUYENG, T - Helmholtz Centre; Hinson, Audra

Submitted to: Journal of Environmental Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/25/2024
Publication Date: 10/31/2025
Citation: Zhang, X., Wang, Y., Lee, S., Liang, K., Zhao, K., Mccarty, G.W., Alfieri, J.G., Moglen, G.E., Hively, W.D., Myers, D., Oviedo-Vargas, D., Nguyeng, T.V., Hinson, A.L. 2025. Synergistic water quality and soil organic carbon sequestration benefits of winter cover crops. Journal of Environmental Management. 371. https://doi.org/10.1016/j.jenvman.2024.123104.
DOI: https://doi.org/10.1016/j.jenvman.2024.123104

Interpretive Summary: Although winter cover crops (WCCs) have been widely adopted in Maryland for water quality benefits, their soil organic carbon (SOC) sequestration impacts in agricultural fields remain largely unknown. Here, we applied the Soil and Water Assessment Tool -Carbon model to quantify the SOC sequestration benefits of six WCCs. In addition to significant reduction in nitrate leaching, we found that adoption of WCCs can sequester 0.45-0.92 MgC ha-1 yr-1, potentially contributing to 2.1-4.4% of Maryland’s 2030 Greenhouse Gases reduction goal. The modeling results also show that adding WCCs into existing crop rotations can increase evapotranspiration and decrease water availability, thereby having negative implications for aquatic ecosystem health and water supply. Sustainable adoption of WCCs requires carefully assessing tradeoffs between water quality, SOC sequestration and water availability.

Technical Abstract: Winter cover crops (WCCs) are promising best management practices for reducing nitrogen and sediment pollution and increasing soil organic carbon (SOC) sequestration in agricultural fields. Although previous watershed studies assessed the water quality benefits of growing WCCs in the Chesapeake Bay watershed, the SOC sequestration impacts remain largely unknown. Here, we designed six WCC scenarios in the Tuckahoe Watershed (TW) to understand potential synergies or tradeoffs between multiple impacts of WCCs. Besides corroborating the nitrate reduction benefits of WCCs that have been reported in previous studies, our results also demonstrated comparable reduction in sediment. We also found that the six WCC scenarios can sequester 0.45-0.92 MgC ha-1 yr-1, with early planted WCCs having more than 70% SOC sequestration benefits compared with their late planted counterparts. With a linear extrapolation to all the cropland in Maryland, WCCs hold potential to contribute to 2.1-4.4% of Maryland’s 2030 Greenhouse Gases reduction goal. Additionally, we showed that WCCs could noticeably increase evapotranspiration and decrease water yield and streamflow, which could negatively impact aquatic ecosystem health and water supply. Overall, this study highlights the potential synergistic water quality and SOC sequestration benefits of WCCs in the Chesapeake Bay watershed. Meanwhile sustainable adoption of WCCs into existing crop rotations will also require careful assessment of consequential water availability.