多因素耦合驱动下黄土高原丘陵沟壑区耕地时空演变及机制分析——以延安市宝塔区为例

Spatio-Temporal Evolution and Mechanism Analysis of Cultivated Land in Hilly and Gully Regions of the Loess Plateau under Multi-Factor Coupling Drive—A Case Study of Baota District, Yan’an City

摘要: 黄土高原丘陵沟壑区是我国生态脆弱、人地矛盾突出的典型区域，厘清其耕地利用变化规律与驱动机制，对区域生态治理、粮食生产保障与农业可持续发展具有重要意义，也契合国家耕地保护与粮食生产保障的核心要求。本研究基于土地利用转型理论框架，以黄土高原“退耕还林(草)”与“治沟造地”两大工程典型示范区——延安市宝塔区为研究区，融合2000、2010、2020年三期Landsat遥感影像与2002~2020年社会经济统计数据，借助ArcGIS空间分析工具，系统解析多因素驱动下的耕地时空演变特征与内在机制。结果表明：1) 2002~2020年宝塔区耕地总量呈持续减少态势，累计净减少30,594公顷，其中新增耕地2119公顷，主要来源为荒地开垦；耕地流失32,749公顷，主导因素为生态退耕。2) 耕地变化呈现显著的两阶段特征：2002~2012年为快速缩减期，受退耕还林(草)政策与城镇化进程驱动，耕地面积大幅下降；2012~2020年为缓减稳控期，受治沟造地工程与粮食安全管控政策影响，耕地缩减趋势显著放缓。3) 以治沟造地典型示范区甘谷驿镇为例，耕地呈现由高海拔向中低海拔、陡坡向缓坡转移的空间重构特征，集中分布于900~1100米海拔区间、10˚~30˚坡度区间，河谷川道优质耕地受城镇建设占用影响显著。基于研究结果，从财政投入、政策引导、农业模式创新、监管机制完善四个方面提出耕地保护对策，可为黄土高原丘陵沟壑区耕地资源可持续利用提供参考。

Abstract: The hilly and gully region of the Loess Plateau is a typical area with fragile ecology and prominent human-land contradiction in China. Clarifying the change law and driving mechanism of its cultivated land use is of great significance for regional ecological governance, food security and sustainable agricultural development, and also meets the key requirements of the national cultivated land protection and food security strategy. Based on the theoretical framework of land use transition, this study takes Baota District of Yan’an City, a typical demonstration area of the “Grain for Green” project and the “Gully Land Consolidation” project on the Loess Plateau, as the research area. It integrates three phases of Landsat remote sensing images in 2000, 2010 and 2020, as well as socio-economic statistical data from 2002 to 2020, and systematically analyzes the spatio-temporal evolution characteristics and internal mechanism of cultivated land driven by the coupling of multiple factors with the help of ArcGIS spatial analysis tools. The results show that: 1) From 2002 to 2020, the total amount of cultivated land in Baota District showed a continuous decreasing trend, with a cumulative net decrease of 30,594 hectares. Among them, the newly increased cultivated land was 2119 hectares, the main source was wasteland reclamation; the lost cultivated land was 32,749 hectares, and the leading factor was ecological conversion. 2) The change of cultivated land presents significant two-stage characteristics: 2002~2012 is a rapid reduction period, driven by the Grain for Green policy and urbanization process, the area of cultivated land decreased significantly; 2012~2020 is a stable control period, affected by the Gully Land Consolidation project and food security control policy, the shrinking trend of cultivated land slowed down significantly. 3) Taking Ganguyi Town, a typical demonstration area of Gully Land Consolidation, as an example, the cultivated land presents a spatial reconstruction characteristic of shifting from high altitude to medium and low altitude, from steep slope to gentle slope, concentrated in the altitude range of 900~1100 m and the slope range of 10˚~30˚. The high-quality cultivated land in river valley is significantly affected by urban construction occupation. Based on the research results, countermeasures for cultivated land protection are put forward from four aspects: financial investment, policy guidance, agricultural model innovation and supervision mechanism improvement, which can provide reference for the sustainable utilization of cultivated land resources in the hilly and gully regions of the Loess Plateau.