Modeling potential impact of agricultural management practices on soil organic carbon changes in US Midwest marginal croplands

Description

Abstract

Although advanced land management practices offer potential for enhancing Soil Organic Carbon (SOC) in marginal croplands, the effects of specific, targeted agricultural interventions on SOC dynamics in degraded soils are still poorly understood and uncertain. In this study, we integrated a high-resolution marginal cropland availability map with the process-based Terrestrial Ecosystem Model (TEM) to quantify SOC sequestration potentials in the US Midwest. We evaluated a comprehensive set of scenarios combining crop rotation, tillage, and fertilization intensities. Our simulations reveal that agricultural management is the primary determinant of the carbon budget on these lands. While conventional practices often led to carbon loss, the optimized strategy, specifically the corn-soybean rotation combined with no-tillage and fertilization, emerged as the most effective approach, achieving a sequestration rate of 2.1 t C ha⁻¹ yr⁻¹. This significantly outperformed continuous corn (0.9 t C ha⁻¹ yr⁻¹) and continuous soybean (0.2 t C ha⁻¹ yr⁻¹) under similar conservation management. Compared to the worst-case scenario (tillage with no fertilization), the best management practice resulted in a net SOC gain of approximately 3.4 t C ha⁻¹ yr⁻¹. These findings demonstrate that adopting integrated management strategies can transform Midwest marginal lands from a potential carbon source into a substantial sink, offering a viable pathway for simultaneously restoring soil fertility and achieving regional carbon sequestration goals.