黄土高原彬长矿区土壤侵蚀特征及其与环境变化的关系

    Spatiotemporal patterns of soil erosion and its relationship with environmental changes in the Binchang mining areas on the Loess Plateau of China

    • 摘要: 黄土高原矿区煤炭产量占全国70%以上,大规模开采活动导致区域内生态环境退化与土壤侵蚀加剧。然而,当前鲜有矿区土壤侵蚀时空特征及其与环境变化关系的定量研究,限制了煤矿区土地复垦与生态修复进展。为了探究矿区土壤侵蚀特征及其与环境变化的关系,为黄土高原煤矿区生态环境治理提供理论指导,该研究以彬长矿区为研究区,利用修订的通用土壤流失方程(revised universal soil loss equation,RUSLE)分别模拟了矿区全区2003—2019年及沉陷区2014—2019年土壤侵蚀速率,探究了矿区全区及沉陷区土壤侵蚀特征,定量研究了降雨、地形和植被对土壤侵蚀的影响。结果表明:1)2003—2019年间,彬长矿区土壤侵蚀速率整体呈显著上升趋势(P<0.05),年份间差异较大,2003年土壤侵蚀最为严重,侵蚀速率为85.56 t/(hm2·a),2009年侵蚀程度最低,侵蚀速率为15.54 t/(hm2·a)。微度、轻度侵蚀主要分布于城区、黄土塬和河流阶地等平坦地区,其空间分布在不同年份间基本保持一致,其余侵蚀类型主要分布于煤矿开采区、沟壑区及河道周边,且侵蚀强度空间异质性较大。2)2014—2019年间矿区全区及沉陷区土壤侵蚀速率表现出明显的季节周期性变化。春秋季节土壤侵蚀强度多表现为微度、轻度侵蚀,冬季侵蚀速率接近于0,夏季土壤侵蚀速率为一年中最高,是矿区水土流失治理的重点时段。3)彬长矿区土壤侵蚀速率与降雨量呈极显著正相关(P<0.01),沉陷区土壤侵蚀速率与降雨量、沉陷量及植被覆盖度均呈极显著正相关(P<0.01),降雨量是土壤侵蚀的主要影响因子,且开采沉陷加剧了土壤侵蚀,沉陷区的沉陷量不同,土壤侵蚀程度也不同。该研究方法探明了矿区的土壤侵蚀变化规律及环境变化对土壤侵蚀的影响,可为黄土高原煤矿区土壤侵蚀防治和生态环境恢复提供决策支持和科学依据。

       

      Abstract: The mining areas of Loess Plateau accounts for over 70% of the total coal production in China, while large-scale coal mining activities have led to seriousecological degradation and intensified soil erosion. However, few studies have quantitatively investigated the spatial pattern of soil erosion rates in mining areas and its relationship with environmental change, largely constraining the implementation of land reclamation and ecological restoration in coal mining areas. In order to provide a theoretical guidance for the eco-environmental management in coal mining areas, this study, taking the Binchang mining area as a study area, derived soil erosion rates of the whole mining area between 2003 and 2019 and the subsidence area between 2014 and 2019, respectively, using the revised universal soil loss equation (RUSLE). We also investigated the spatial pattern of soil erosion rates for the whole mine area and the subsidence area and quantitatively studied the effects of precipitation, topography and vegetation cover on soil erosion rates. Results showed that: 1) During 2003-2019, soil erosion rates in the Binchang mining area showed a significant upward trend (P<0.05), with the highest and lowest rates of 85.56 and 15.54 t/(hm2·a) emerging in 2003 and 2009 respectively. Slight and light erosion was mainly distributed in flat areas such as urban areas, loess tableland and river terraces, with a consistent spatial distribution, while other levels of soil erosion intensity were mainly distributed in the coal mining area, gully areas and areas around river channels and were of high spatial hetergeneous. 2) During 2014-2019, soil erosion rates of the whole mining area and the subsidence area changed between seasons. Slight and light erosion mostly occurred in spring and autumn, while erosion rate in winter was close to 0, and highest erosion rates occurred in summer . This demonstrated that soil erosion control should be primarily undertaken in Summer in the Binchang mining area. 3) Erosion rates in the Binchang mining area were significantly positively correlated with precipitation (P<0.01), while that in the subsidence area was significantly positively correlated with precipitation, height of subsidence, and vegetation cover (P<0.01). Precipitation was the main influencing factor of soil erosion in the Binchang mining area, while the surface subsidence caused by coal mining exacerbated soil erosion. Erosion rates also varied with changes in height of subsidence. This study revealed that the spatial pattern of erosion rates in the coal mining area and its relation with environmental change, which provided a useful reference for erosion control and ecological restoration in the coal mining area of the Loess Plateau.

       

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