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生态退耕是调整陆地生态系统结构与功能以应对土地利用过度干扰的重要途径之一,因此科学掌握退耕格局与耕地格局演变对黄土高原生态环境治理与生态修复具有深远意义。本文以位于黄土高原的延安市为典型区,从生态退耕的整体特征、地形因素及区域差异等角度,探究生态退耕以来其耕地变化及退耕状况的空间分异特征。结果表明:生态退耕致使延安市耕地面积由2000年的11 752.80 km2减少为2013年的9149.93 km2,退耕面积为2756.85 km2,退耕指数为22.15%,且退耕耕地主要转化为林地、草地,占退耕面积的95.29%;耕地与退耕面积主要分布于6~15°、15~25°坡度及第II级(925~1115 m)、第III级(1115~1275 m),且2005-2013年的生态退耕速率均高于2000-2005年的生态退耕速率;县域退耕面积及退耕程度均呈现由北向南依次递减的分异特征,而退耕重心与耕地重心均在延安市几何中心以北的安塞县与宝塔区边界,且生态退耕的重心由东北向西南方向迁移,耕地重心则由北向南迁移。本文通过对延安市生态退耕的时空分异特征分析可为黄土高原更加科学合理地推进生态保育与生态文明建设提供参考。
Ecological restoration of cultivated land is one of the important ways to adjust the structure and function of terrestrial ecosystems to cope with excessive land use disturbance. Therefore, it is of great significance to grasp the pattern of returning farmland and the evolvement of cultivated land pattern to ecological environment and ecological restoration in the Loess Plateau. In this paper, Yan’an City, located in the Loess Plateau, is a typical area. From the perspectives of overall characteristics, topographical factors and regional differences of ecological restoration, the spatial heterogeneity of cultivated land changes and returning farmland to the environment is discussed. The results showed that the area of farmland in Yan’an decreased from 11 752.80 km2 in 2000 to 9149.93 km2 in 2013, with an area of 2756.85 km2 and a withdrawal index of 22.15%. The area of returned farmland was mainly converted into forest land and grassland, And 95.29% respectively. The area of cultivated land and area for returning cultivated land mainly distributed in slope of 6 ~ 15 °, 15 ~ 25 ° and grade II (925 ~ 1115 m), grade III (1115 ~ 1275 m) The rate of returning farmland to farmland and the degree of returning farmland all showed the characteristics of descending from north to south in descending order, while the center of gravity of returning farmland and the center of gravity of farmland all occurred in Ansai County, north of the geometric center of Yan’an City and Pagoda border, and the focus of ecological retreat from northeast to southwest migration, arable land center of gravity from north to south migration. In this paper, through analyzing the spatial and temporal differentiation characteristics of ecological restoration in Yan’an City, this paper can provide reference for the Loess Plateau to promote ecological conservation and ecological civilization more scientifically and reasonably.