2000—2024年黑土区退化耕地识别与时空变化特征

Identification and Spatiotemporal Variation Characteristics of Degraded Cultivated Land in Black Soil Region from 2000 to 2024

摘要:

黑土区是保障国家粮食安全的基石，由于过度利用和管护不当，黑土区耕地产生了退化问题。受限于数据获取难、处理流程复杂等问题，黑土区退化耕地时空变化特征尚未达成共识。本文基于SDG15.3.1框架，选取土地生产力、土地覆被、土壤有机碳指标，以2000年为基准期，运用Trends.Earth工具系统识别并分析了2005、2010、2015、2020、2024年黑土区退化耕地时空变化特征，并与黑土区退化评估相关研究进行对比验证。结果表明，2000—2024年，黑土地退化耕地持续下降，呈阶段性变化特征，从30.76%降至16.96%，降幅达13.80个百分点，区域耕地退化态势总体有所缓解，仍有16.96%的耕地存在退化问题，主要集中于松嫩平原区北部与中部、三江平原区东北部及大小兴安岭沿麓区西南部。从子指标来看，土地生产力退化耕地占比从19.16%降至4.21%，土地覆被指标从14.05%降至10.74%，而土壤有机碳退化耕地占比从1.44%升至8.85%。从退化趋势空间分布来看，保持稳定（53.54%）与恢复趋势（40.49%）耕地占主体，仅5.97%的耕地呈加剧退化趋势，退化耕地空间分布范围趋于收敛且重心整体向西南偏移。对比验证结果表明，识别结果与已有农田退化、土壤侵蚀、黑土层减薄及耕地质量退化研究结论基本一致，结果具有较好可靠性。总体而言，2000—2024年黑土区退化问题有所缓解，但仍有近五分之一耕地存在退化问题，局部区域退化风险依然突出。未来应立足黑土区耕地退化区域分异特征实施差异化治理，以保障黑土地可持续利用和粮食安全。

Abstract:

As a pillar of national food security, the black soil region faces cultivated land degradation from overuse and mismanagement, yet a consensus on its spatiotemporal dynamics remains elusive due to data and methodological constraints. Based on the SDG15.3.1 framework, the land productivity, land cover, and soil organic carbon were selected as indicators, taking the year of 2000 as the baseline period, and the Trends.Earth tool was used to systematically identify and analyze the spatiotemporal variation characteristics of degraded cultivated land in the black soil region in 2005, 2010, 2015, 2020, and 2024, and comparatively validated the results against relevant studies on degradation assessment in the black soil region. The results showed that: from 2000 to 2024, the proportion of degraded cultivated land declined from 30.76% to 16.96%, representing a decrease of 13.80 percentage points, although marked stage-specific variations were observed. The overall trend of cultivated land degradation in the region was alleviated to some extent, but 16.96% of the cultivated land still had degradation problems, mainly concentrated in the northern and central parts of the Songnen Plain, the northeastern part of the Sanjiang Plain, and the southwestern part of foothills of Greater and Lesser Khingan Mountains. From the perspective of sub-indicators, the proportion of degraded cultivated land in terms of land productivity was decreased from 19.16% to 4.21%, the proportion of degraded cultivated land in terms of land cover was decreased from 14.05% to 10.74%, and the proportion of degraded cultivated land in terms of soil organic carbon was increased from 1.44% to 8.85%. From the perspective of the spatial distribution of degradation trends, cultivated land with stable trends (53.54%) and recovery trends (40.49%) accounted for the majority, while only 5.97% of the cultivated land showed an aggravated degradation trend. The spatial distribution range of degraded cultivated land tended to converge, and the center of gravity shifted southwestward overall. Comparative validation showed that the identification results were generally consistent with previous findings on cultivated land degradation, soil erosion, black soil layer thinning, and cultivated land quality degradation, indicating good reliability. Overall, black soil degradation eased between 2000 and 2024, yet nearly one-fifth of cultivated land remained degraded with localized risks. Differentiated governance was thus required to safeguard black soil sustainability and food security.