Synergistic effects of cover crops on productivity enhancement and carbon sequestration with emission reduction in multiple cropping systems of southern China

The southern part of China abounds in water and heat resources. Developing multiple cropping systems in this region has long been recognized as a crucial strategy for safeguarding national food security. The expansion of these systems has driven the rapid growth of cover crops, positioning the region as a key production area for cover crops in China. Recently, many studies have shown the critical role of cover crops in addressing challenges such as low resource use efficiency, high greenhouse gas emissions, and soil degradation in southern China’s intensive cropping systems. However, in the southern regions of China, the adoption of cover crops within complex multiple cropping systems is currently hindered by disorganized planting systems, rigid variety selection, and insufficient farmer incentives. While prior research has predominantly focused on single-factor or single-region analyses, the comprehensive effects of cover crops in the agroecological context of China's southern multiple cropping systems, along with their underlying mechanisms driving high-yield efficiency and carbon sequestration with emission mitigation, remain insufficiently elucidated. This review systematically examines the current status, challenges, and research advancements in cover crop integration within southern China’s multiple cropping systems. Key mechanisms by which cover crops enhance productivity and sustainability are analyzed, including: increasing exogenous organic matter input to improve soil physicochemical and biological properties; fostering synergistic interactions with primary crops under intercropping or rotation systems; and reducing agricultural inputs while optimizing resource use efficiency. Finally, in light of the issues currently present in the development of cover crops, we suggest that when implementing the cultivation of cover crops in this region, measures should be taken to suit local conditions and seasonal factors. Starting from the regional characteristics and integrating the actual cropping systems with the dominant cultivated crops, appropriate cover - crop varieties and planting patterns ought to be chosen. By elucidating the synergies between yield efficiency and soil carbon sequestration, this study aims to provide a theoretical foundation and practical insights to guide the green development and scalable adoption of cover crops in southern China’s agricultural systems.