内蒙古黄土高原土壤侵蚀时空分布特征及其影响因素分析

Characterization of Spatial and Temporal Distribution of Soil Erosion on the Loess Plateau of Inner Mongolia and Analysis of Its Influencing Factors

  • 摘要: 基于土壤侵蚀数据,对2001—2020年的土壤侵蚀变化状况进行了研究,结合来自自然、社会经济和地理区位的多源数据,运用随机森林回归模型,对所选的10个影响因素进行重要性排序,并对不同年份土壤侵蚀预测值和实际值进行比较。结果表明:内蒙古黄土高原从2001—2020年平均土壤侵蚀模数从1221.96 t/(km2·a)变为155.97 t/(km2·a),主要以微度和轻度侵蚀占比最大,20 a间微度侵蚀面积有所增加,轻度、中度和强烈侵蚀有所减少。根据模型结果显示,在内蒙古黄土高原地区影响土壤侵蚀发生显著的因素有5个,其中坡度是最显著影响土壤侵蚀发生的因素,其他显著因素的重要性排序为距居民点最近距离 > 距道路最近距离 > NDVI > 年均降水量;模型的R2=0.89,说明拟合结果较好,表明该模型适用于内蒙古黄土高原地区的土壤侵蚀量预测。通过绘制土壤侵蚀发生风险图,发现土壤侵蚀发生概率高的地方主要集中在内蒙古黄土高原北部、东北部的呼和浩特市和包头市以及西部的阿拉善左旗,这些地区受人类开发活动和自然因素共同作用比较明显。

     

    Abstract: Based on soil erosion data, the changing status of soil erosion was studied, combining multi-source data from nature, socio-economics and geographic location, applying a random forest regression model to rank the importance of the selected 10 influencing factors, and comparing the predicted and actual values of soil erosion in different years. The results indicated that the average soil erosion modulus on the Loess Plateau of Inner Mongolia changed from 1221.96 t/(km2·a) to 155.97 t/(km2·a) from 2001 to 2020, mainly with the largest proportion of slight and light erosion, and the area of slight erosion increased and the area of light, moderate and strong erosion decreased during 20 years. According to the model results, there are 5 factors that significantly affect the occurrence of soil erosion in the Loess Plateau area of Inner Mongolia. Among these factors, slope is the most significant factor that affects the occurrence of soil erosion. The other significant factors are ranked in order of importance: nearest distance to settlement > nearest distance to road > NDVI > average annual precipitation; R2 value of the model was 0.89, indicating a good fit and applicability to predicting soil erosion in the Loess Plateau region of Inner Mongolia. A risk map of soil erosion occurrence revealed that areas with high probability of soil erosion were mainly concentrated in the northern part of the Inner Mongolia Loess Plateau, Hohhot and Baotou in the northeast, and Alxa Left Banner in the west, which were more significantly affected by the combined effect of human development activities and natural factors.

     

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