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摘要 基于2000～2010年土地利用/覆被变化、植被覆盖度、坡耕地分布等数据，分析陕甘宁退耕还林/草工程区耕地转换为林地或草地状况、不同坡耕地退耕情况及退耕区植被覆盖度变化等，从而揭示该区域退耕還林/草工程的生态成效。结果表明：①2000～2010年，陕甘宁退耕还林/草工程区耕地面积减少了9 501.12 km2，减少比例占工程区总面积的1.41%，其中2 168.80 km2和6 753.48 km2分别转变为林地和草地，分别占减少耕地面积的22.83%和71.08%，以退耕还草为主说明工程实施过程中考虑了干旱/半干旱区水热条件限制。②2000～2010年，研究区地表植被覆盖度增加了8.37个百分点，呈现较明显的增长趋势，其中耕地转林地区域增加了14.63个百分点，耕地转草地区域增加了18.06个百分点，达到甚至超过了工程区林草覆盖率增加的规划目标。③2000～2010年，陕甘宁退耕还林/草工程区内大于15°坡耕地面积减少了1 800.02 km2，其中15°～25°坡耕地转换为林地和草地面积为408.68 km2和10 48.04 km2，大于25°坡耕地转为林地和草地面积分别为149.83 km2和152.36 km2。
关键词 陕甘宁地区；退耕还林/草；土地利用变化；植被覆盖度；生态成效
中图分类号 S725.7 文献标识码 A 文章编号 0517-6611（2014）17-05524-05
Abstract Based on data of land use/coverage change， vegetation coverage， slope land distribution during 2000-2010， the conversion of cropland to forest or grassland condition， the vegetation coverage change were analyzed， so as to reveal ecological effectiveness of GrainforGreen project in ShanxiGansuNingxia region. The results are shown as follows.① From 2000 to 2010， farmland in the ShanxiGansuNingxia Region decreased by 9 501.12 km2， with the reducing proportion of 1.41% accounted for the total area of the study area. Converted from farmland to forest and grassland were 2 168.80 km2 and 6 753.48 km2， which accounted for 22.83% and 71.08% of reduced farmland， respectively.②From 2000 to 2010， the vegetation coverage was improved progressively， the average coverage of the whole study area increased by 8.37 percentage points. Among them， the coverage of regions with farmland to forest increased by 14.63 percentage points， and the coverage of regions with farmland to grassland increased by 18.06 percentage points.③In resent ten years， the area of farmland with slope greater than 15°decreased by 1 800.02 km2. In which， farmland with slops between 15°-25° slope， 408.68 km2 and 1 048.04 km2 were converted to forest and grassland respectively. The farmland with slops more than 25°， with 149.83 km2 and 152.36 km2 transferred to forest and grassland respectively.
Key words ShanxiGansuNingxia Region； Grain for Green Program； Land use change； Vegetation coverage； Ecological effectiveness
黄土高原是我国水土流失最严重的区域，超过60%的土地存在土壤质量退化问题，年平均土壤流失量为2 000～2 500 t/km2，土质山坡道路路面土壤侵蚀模数高达3.49万～9.02万t2/km2 [1-2]。地形破碎、土壤疏松、植被稀疏以及不合理的土地利用结构是黄土高原地区水土流失严重和生态环境退化的主要原因[3]。随着生态环境的日益恶化，土地资源的合理利用受到越来越多人们的重视[4]。从1999年开始，我国开始实施退耕还林还草工程，以此来减少水土流失和土壤侵蚀等生态环境问题[5-6]。陕甘宁地区的主体位于黄土高原中部丘陵沟壑区[7]，是我国退耕还林/草工程的典型区[8]。准确掌握退耕还林/草对区域生态环境的影响，对退耕还林还/草工程的可持续发展具有极其重要的意义。
关键词 陕甘宁地区；退耕还林/草；土地利用变化；植被覆盖度；生态成效
中图分类号 S725.7 文献标识码 A 文章编号 0517-6611（2014）17-05524-05
Abstract Based on data of land use/coverage change， vegetation coverage， slope land distribution during 2000-2010， the conversion of cropland to forest or grassland condition， the vegetation coverage change were analyzed， so as to reveal ecological effectiveness of GrainforGreen project in ShanxiGansuNingxia region. The results are shown as follows.① From 2000 to 2010， farmland in the ShanxiGansuNingxia Region decreased by 9 501.12 km2， with the reducing proportion of 1.41% accounted for the total area of the study area. Converted from farmland to forest and grassland were 2 168.80 km2 and 6 753.48 km2， which accounted for 22.83% and 71.08% of reduced farmland， respectively.②From 2000 to 2010， the vegetation coverage was improved progressively， the average coverage of the whole study area increased by 8.37 percentage points. Among them， the coverage of regions with farmland to forest increased by 14.63 percentage points， and the coverage of regions with farmland to grassland increased by 18.06 percentage points.③In resent ten years， the area of farmland with slope greater than 15°decreased by 1 800.02 km2. In which， farmland with slops between 15°-25° slope， 408.68 km2 and 1 048.04 km2 were converted to forest and grassland respectively. The farmland with slops more than 25°， with 149.83 km2 and 152.36 km2 transferred to forest and grassland respectively.
Key words ShanxiGansuNingxia Region； Grain for Green Program； Land use change； Vegetation coverage； Ecological effectiveness
黄土高原是我国水土流失最严重的区域，超过60%的土地存在土壤质量退化问题，年平均土壤流失量为2 000～2 500 t/km2，土质山坡道路路面土壤侵蚀模数高达3.49万～9.02万t2/km2 [1-2]。地形破碎、土壤疏松、植被稀疏以及不合理的土地利用结构是黄土高原地区水土流失严重和生态环境退化的主要原因[3]。随着生态环境的日益恶化，土地资源的合理利用受到越来越多人们的重视[4]。从1999年开始，我国开始实施退耕还林还草工程，以此来减少水土流失和土壤侵蚀等生态环境问题[5-6]。陕甘宁地区的主体位于黄土高原中部丘陵沟壑区[7]，是我国退耕还林/草工程的典型区[8]。准确掌握退耕还林/草对区域生态环境的影响，对退耕还林还/草工程的可持续发展具有极其重要的意义。