A Preliminary Comparison of SOC Storage Between the Traditional Farmland and Well-Facilitated Farmland Management

Abstract

Soil organic carbon (SOC) is central to the global carbon cycle, yet unsustainable cultivation has resulted in a continuing SOC loss and has made it highly vulnerable to future climate change. In China, the Well-Facilitated Farmland Construction (WFC) initiative has sought to enhance soil conditions by integrating farmland management units (FMUs) and adopting improved practices, including optimized irrigation, straw incorporation, and targeted fertilization strategies. Since its launch in 2013, the WFC project has been implemented across more than 50 million hectares of farmland. However, its spatio-temporal impacts on SOC remain poorly understood. To address this gap, we focused on three representative regions, Shunyi, Rudong, and Dangtu, to examine the impact of farmland management unit integration. A total of 1,549 soil profiles were compiled to calibrate the CENTURY model and simulate long-term variations in topsoil (0–20 cm) SOC density (SOCD) across Chinese farmlands. Results show that, following the WFC project, farmland fragmentation decreased while SOCD increased, with strong negative correlations between fragmentation degree and SOCD. These findings indicate that farmland patch integration contributes significantly to SOC sequestration. According to the results of future simulation, the WFC practices would increase the farmland SOC storage under the SSP1-2.6 and SSP5-8.5 climate scenarios during the 2030–2100. This sustained increase reflects the CO₂ fertilization effect, enhanced crop productivity through optimized irrigation, greater organic inputs from straw incorporation, and reduced microbial decomposition under balanced nitrogen fertilization. In conclusion, WFC demonstrates a sustainable pathway toward more resilient and climate-smart food systems.