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中国不同区域撂荒耕地的空间异质性和驱动机制分析

Spatiotemporal heterogeneity and driving mechanisms of cropland abandonment across different regions in China

  • 摘要: 耕地撂荒是全球普遍存在的土地利用变化问题,直接威胁粮食安全稳定与土地资源可持续发展。然而,我国耕地撂荒的长期演变规律、区域差异及驱动机制仍缺乏系统认识。该研究采用土地利用轨迹变化检测法,构建1995—2023年中国耕地撂荒的空间信息数据集,系统分析耕地撂荒的时空演变特征与空间集聚格局,并利用可解释机器学习模型揭示全国及不同农业区撂荒形成机制及其时序变化特征。结果表明:(1)1995—2023年中国耕地撂荒总体呈波动上升趋势,撂荒面积由7.59万km2增加至18.22万km2,撂荒率由4.33%上升至10.35%。其中,2000—2010年为快速扩张阶段,2010年后增速趋缓,2020—2023年出现小幅下降,但总体撂荒水平仍处于较高状态。(2)中国耕地撂荒具有明显空间集聚特征,高值区主要集中于黄土高原、内蒙古及长城沿线区和西南山区等生态脆弱、地形复杂区域,低值区则主要分布于东北平原、黄淮海平原和长江中下游平原等粮食主产区。南北方撂荒时长结构差异明显,南方农业区短期撂荒占比更高,持续时间普遍短于北方。(3)全国尺度上,地形、气候等自然条件是影响耕地撂荒的主导因子,自然因素总体强于经济社会因素。农业区间驱动机制存在显著差异,西北干旱区与东南区主要受气候条件影响,高原及山地区域以地形约束为主,而西南区和江南丘陵山区则更多受到经济社会因素驱动。2000—2023年间,人口密度与经济发展水平在部分农业区撂荒驱动中的重要性显著增强。研究结果有助于深化对我国耕地撂荒时空演变规律及驱动机制的认识,可为分区开展耕地保护、撂荒治理及土地资源优化配置提供科学依据。

     

    Abstract: Cropland abandonment is a widespread global land-use change issue that directly endangers food security and the sustainable utilization of land resources. Nevertheless, the long-term evolutionary patterns, regional disparities and driving mechanisms of cropland abandonment across China remain insufficiently understood systematically. This study addresses that gap by constructing a spatially explicit dataset of abandoned cropland across China for 1995–2023 and investigating spatiotemporal dynamics, spatial clustering, and driving mechanisms at national and agricultural sub-regional scales.Abandoned cropland was identified by integrating two complementary land-cover datasets: the China Land Cover Dataset (CLCD) at 30 m annual resolution, and the China Multi-period Land Use Remote Sensing Monitoring Dataset (CNLUCC) used as a cropland mask to constrain detection domain and reduce misclassification. A temporal consistency correction was applied to CLCD time series via a five-year sliding window to eliminate spurious land-cover transitions caused by classification errors or cloud contamination. A pixel-level land-use trajectory coding framework for the 1990–2023 sequence was adopted to identify cropland continuously converted to non-land for two or more consecutive years, the abandonment threshold matching China’s high-intensity farming conditions. We quantified abandonment for seven target years and classified plots into short-term (≤10 years), medium-term (10–20 years), and long-term (>20 years) groups by abandonment duration, which serves as a critical basis for differentiated reclamation planning. Based on 13 multi-dimensional variables covering terrain, climate, soil, population and economy, an interpretable XGBoost-SHAP framework was built to quantify factor importance and directional effects in 2000, 2010 and 2023, revealing temporal shifts of abandonment drivers nationwide and in sub-regions.The results showed abandoned cropland expanded from 75,900 km2 in 1995 to 182,200 km2 in 2023, with the abandonment rate rising from 4.33% to 10.35% in a fluctuating upward trend: abandonment expanded rapidly during 2000–2010, slowed after 2010, and slightly declined between 2020 and 2023 yet stayed at a high level. Obvious spatial clustering emerged: high-abandonment hotspots clustered along the Hu Huanyong Line, including the Loess Plateau, Inner Mongolia and Great Wall Fringe, and mountainous Southwest China, while low-abandonment cold spots concentrated in major grain-producing plains. Southern agricultural regions were dominated by short-term abandonment, whereas northern plateau and agro-pastoral transition zones held more medium and long-term abandoned land.Nationwide, topographic indicators and annual temperature served as dominant drivers, with natural constraints stronger than socioeconomic factors. Agricultural divisions presented divergent driving patterns: the arid Northwest and Southeast were climate-controlled with opposite temperature effects; the Loess Plateau, Inner Mongolia fringe, Huang-Huai-Hai and Middle-lower Yangtze zones were restricted by stable terrain and hydrothermal conditions; Northeast, Southwest and South Yangtze hilly areas were jointly shaped by natural conditions and rising population outflow. The Qinghai-Tibet Plateau was uniquely governed by elevation with nonlinear altitudinal effects, and regional economic development gained growing explanatory power. From 2000 to 2023, population density and economic level carried rising explanatory weight in most zones, reflecting stronger coupling between natural endowments, urbanization and labor migration.This research innovatively couples long-time-series trajectory detection with interpretable machine learning to distinguish abandonment duration gradients and compare zone-specific driving dynamics over nearly 20 years. It provides empirical evidence for differentiated abandoned cropland governance and hierarchical reclamation strategies.

     

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