南方红壤丘陵区退耕还林还草工程土壤保持效应评估

以南方红壤丘陵区为研究对象，应用修正通用土壤流失方程，根据2000年、2005年、2010年、2015年土地利用数据，识别出了近15年南方红壤丘陵区退耕还林还草的空间范围，并估算了退耕还林还草实际发生区的土壤保持效应。结果表明，2000—2015年，南方红壤丘陵区退耕还林还草面积约2 052.61 km²。期间土壤保持量增加9.18×10⁸ t，单位面积土壤保持量变化量为447 327.54 t/km²，土壤保持效应整体显著提升，但仍有部分区域出现负效益。此外，对提升土壤保持功能而言，将裸地转换为林地是效果最显著的土地利用变化方式。退耕还林还草的实施提高了区域的土壤保持功能。研究结果对南方红壤丘陵区退耕还林还草工程的实施及管理具有指导意义。

Soil Conservation Benefits of the Grain for Green Program in the Hilly Red Soil Region of Southern China

The soil erosion in hilly red soil region (HRSR) of southern China has a serious impact on the local ecological environment. The government has implemented a series of ecological projects to control soil erosion. However, there are few studies on the ecological effects of ecological projects such as the Grain for Green Program (GFGP) in the southern region. This paper selected the hilly red soil region of southern China as the research area. Based on the land use data in 2000, 2005, 2010, and 2015, we identified the spatial extent of the Grain for Green Program (GFGP) in HRSR. We also estimated the effect of soil conservation in areas where the GFGP actually occurred by the Revised Universal Soil Loss Equation (RUSLE). The results showed that from 2000 to 2015, the GFGP area in the HRSR was about 2 052.61 km². During this period, soil conservation quantity increased by 918 million tons, and the change in soil retention per unit area was 447 327.54 t/km². The overall soil conservation effect was significantly improved, but some areas still had negative benefits. In addition, the conversion of bare land into forest land was the most effective way of land use change for improving soil conservation services. The implementation of GFGP improved the regional soil retention function. This study has guiding significance for the implementation and management of the GFGP in hilly red soil region of southern China.