Backgrounds A large-scale ecological restoration project has been initiated since 1990s in southwest China, which is one of the largest areas of rocky desertification globally. However, the different influences and potential mechanisms of vegetation restoration on soil carbon(C) sequestration in karst and non-karst regions are still unclear.
Methods Based on field investigation and multi-source data synthesis, the mechanisms of soil C sequestration were investigated to determine the most important variables affecting the rate of soil C change (Rs) in southwest China.
Results Our results show significant differences in soil C sequestration between karst and non-karst regions with faster and longer C sequestration in karst regions, where Rs was approximately 31 % higher than in non-karst soils. And temperatures could be the primary factor inhibiting soil C sequestration without precipitation. The total effect of nitrogen (N) on Rs was positive in both karst and non-karst regions.
Conclusions Phosphorus was the dominant factor limiting the use of N in karst regions and then resulting in limitation of C sequestration. The results indicated that soil C storage could be led to intensify uneven increases due to combination of karst environment and climate change in southwest China in future.