退耕还林工程建设对吴起县土地利用/覆被变化及其土壤侵蚀的影响

为研究退耕还林工程建设对吴起县土地利用/覆被变化及其土壤侵蚀的影响，基于3S技术与RUSLE土壤侵蚀模型，分析评价了该县退耕还林前后土地利用/覆被、土壤侵蚀的时空变化。结果表明:吴起县实施退耕还林后10 a来，各种土地利用类型之间发生了较为复杂的转化，耕地面积比退耕前减少66.51%，林地面积比退耕前增加了212.61%；水土流失控制效果明显，全县平均土壤侵蚀模数由退耕还林前的9 779 t/（km²·a）减少为退耕还林后的5 285 t/（km²·a），减少了45.96%，退耕还林后全县每年可减少土壤侵蚀量约1 704万t；土壤侵蚀与土地利用类型关系密切，未利用地的侵蚀最严重，其平均土壤侵蚀模数为19 513 t/（km²·a），为林地土壤侵蚀模数平均值856 t/（km²·a）的22.79倍；研究结果将对该区域水土流失控制及其土地资源的合理利用提供参考依据。

Effect of Conversion of Cropland to Forestland on Soil Water Erosion and Land Use/Cover in Wuqi County

To study the impact of conversion of cropland to forestland project on land use change/cover and soil erosion in Wuqi County in this paper, based on 3S technology and RUSLE soil erosion model, the analysis and evaluation of the county, returning farmland to forest and land use/cover, the temporal and spatial changes of soil erosion were carried out. The results showed that the implementation of returning farmland to forestland in Wuqi County after 10 years, various types of land use complex changes happened between cultivated land area, 66.51% less than before returning cultivated land, forest area increased by 212.61% than before project, soil erosion was obvious controlled effect, the average soil erosion modulus was 9 779 t/(km²·a) before the project, and it was 5 285 t/(km²·a) after the conversion of cropland to forestland, the reduction percentage was 45.96%, after conversion of cropland to forestland in the county to the annual reduction amount of soil erosion was about 1.704×10⁷ t. Soil erosion and land use types were closely related, the most serious erosion occured on unused land, the average soil erosion modulus was 19 513 t/(km²·a), which is 22.79 times of average modulus with 856 t/(km²·a) in forestland; the study results will provide reference to soil erosion control and rational use of land resources in this region.