Vegetation restoration promotes glomalin-related soil protein accumulation via mineral interactions in a Karst Region, southwest China

Abstract

Glomalin-related soil protein (GRSP), a key biomolecule regulating soil organic carbon (SOC) dynamics, plays a critical role in promoting SOC storage and stabilization. However, its response to vegetation restoration in high-mineral karst ecosystems remains poorly understood. This study investigated the effects of vegetation restoration (cropland, shrubland, and secondary forest) on GRSP accumulation and its contribution to SOC in a karst region of southwest China. Vegetation restoration significantly increased SOC and total GRSP contents, with secondary forest exhibiting 211.2 % higher SOC and 55.3 % higher total GRSP compared to cropland. Conversely, total GRSP's contribution to SOC decreased by 50.3 % in the secondary forest relative to cropland, likely due to the “dilution effect” from increased plant-derived carbon inputs. Random forest modeling showed that soil minerals (e.g., exchangeable Ca/Mg) and labile nitrogen were key factors in regulating total GRSP accumulation. This study highlights the pivotal role of soil minerals in mediating GRSP accumulation during vegetation restoration, providing new insights into microbial-controlled carbon sequestration mechanisms in karst ecosystems. These findings are crucial for optimizing ecological restoration strategies to enhance long-term soil carbon storage in mineral-rich environments.