Effects on soil organic carbon accumulation and mineralization of long-term vegetation restoration in Southwest China karst

Vegetation restoration significantly changes soil organic carbon (SOC) accumulation and mineralization, obvi-ously affects soil carbon pool. To clarifying effects of vegetation restoration on SOC accumulation and miner-alization is of great significance in reducing carbon emission and increasing carbon sequestration. In the present study, the effects on SOC accumulation and mineralization of four types of vegetation restoration engineering including seven species planting measures, all carried out for 28-31 years, were studied. Results showed the long-term vegetation restorations had significant effects on SOC accumulation and mineralization. Tree and vine forest construction measures significantly increased total SOC content and reserves, recalcitrant organic carbon content and proportion, and also obviously raised SOC mineralization rate and cumulative mineralization amount. Grassland construction measures significantly reduced total SOC content and reserves, obviously increased the proportion of soil active organic carbon, and also remarkably raised SOC cumulative mineraliza-tion proportion. In addition, the long-term vegetation restoration measures significantly changed the tempera-ture sensitivity of SOC mineralization. The long-term vegetation restoration has remarkable effects on SOC mineralization and accumulation in Southwest China karst area. In the restoration, tree and vine forest con-struction measures should be preferred, and grassland construction measures should not be implemented. The present study results provide theoretical bases for scientific vegetation restoration of degraded karst ecosystems in Southwest China Karst and are of great significances in reducing soil carbon emission and increasing soil carbon sequestration.