To support targeted policy‑making for the Grain for Green Program (GFGP) in karst regions, taking Guangxi as an example, this study employs cropland utilization transfer matrices, ArcGIS spatial analysis, and centroid migration models to measure the spatial differentiation patterns and evolutionary characteristics of the carbon sequestration effects of the GFGP from 2000 to 2022. The results show that 1) carbon sequestration in project implementation areas increased significantly, with an average carbon sequestration increment of 393.92 gC/m². Spatially, it exhibited a dual-core agglomeration pattern of “central karst core area–southern coastal contiguous area”. The centroid of carbon sequestration shifted northward as the policy implementation gradually tilting towards ecologically fragile karst areas. 2) Carbon sequestration effects varied significantly among different GFGP conversion types. Conversion to shrubland emerged as the optimal pathway, with the highest average carbon sequestration increment of 483.74 gC/m². 3) Significant spatial differentiation in carbon sequestration effects existed between karst and non-karst areas. High-value carbon sequestration areas in non-karst regions were continuously distributed, while in karst regions, high-value areas were scattered and significantly constrained by site conditions. Shrub and grass restoration performed well in karst areas, whereas forest restoration exhibited a relatively weaker carbon sequestration effect due to geological limitations. Vegetation types for the GFGP should be configured according to local conditions, and differentiated management should be strengthened to enhance carbon sequestration benefits.

为实现喀斯特地区退耕还林工程的精准施策, 以广西为例, 采用耕地利用转移矩阵、ArcGIS空间分析与重心迁移模型, 测度2000—2022年退耕还林(草)的碳汇效应时空分异格局及演变特征, 得到以下结果。1) 工程实施区碳汇显著提升, 平均固碳增量达到393.92 gC/m², 空间分布呈“中部岩溶核心区–南部沿海连片区”双核集聚格局, 随着政策实施逐步向生态脆弱的岩溶区倾斜, 碳汇重心北移; 2) 不同退耕类型碳汇效应差异显著, 退耕还灌以483.74 gC/m² 的固碳增量均值成为最优路径; 3) 岩溶与非岩溶区碳汇效应空间分异显著, 非岩溶区碳汇高值区连片分布, 岩溶区高值区零散且受立地条件制约明显。还灌和还草在岩溶区表现良好, 还林受岩溶地质限制碳汇效应相对较弱。退耕还林应因地制宜地配置植被类型, 强化差异化管理, 以便提升碳汇增效水平。