沙漠化逆转过程中毛乌素沙地土壤风蚀可蚀性影响因子的变化特征

目的]揭示毛乌素沙地沙漠化逆转过程对土壤风蚀可蚀性的影响，为该区风蚀防治和生态重建提供科学参考。方法]选取1986—2021年共8期遥感影像，以ENVI 5.3和ArcGIS 10.7为平台对毛乌素沙地不同时期土地沙漠化进行反演，同时构建研究区2021年沙漠化差值指数(DDI),并按照自然断裂法将毛乌素沙地土地分为非、轻度、中度、重度和极重度5种沙漠化类型代表沙漠化逆转的不同阶段。根据反演结果，应用空间代替时间的方法，对不同沙漠化类型土壤进行样品采集，并对土壤机械组成、土壤有机质含量、土壤结皮、植被因子等土壤风蚀可蚀性影响因子进行测试分析。结果]毛乌素沙地1986—2021年沙漠化整体呈逆转趋势，沙漠化土地面积由1986年的47 877.81 km²缩减至2021年的45 914.06 km²,以56.11 km²/a的速率逆转。该区土地沙漠化可分为3个时期：1986—2001年为沙漠化发展期，土壤黏粒、粉粒百分含量、有机质含量呈降低趋势，土壤砂粒百分含量、结皮因子和植被因子值呈增加趋势；2001—2011年为沙漠...

Characteristics of Changes in Factors Influencing Wind Erosion and Erodibility of Soils in Mu Us Sandland During Desertification Reversal

Objective] The influences of the desertification reversal process on soil wind erosion in the Mu Us sandland were studied in order to provide a scientific reference for the prevention and control of wind erosion and for ecological reconstruction in this area. Methods] A total of eight remote sensing images were selected from 1986 to 2021, and ENVI 5.3 and ArcGIS 10.7 were used as the platform to invert the desertification of land in different periods in the Mu Us sandland. A desertification difference index (DDI) was constructed for the study area in 2021, and land in the Mu Us sandland was classified as non-, light, moderate, severe, and very severe desertification according to the natural fracture method. According to the inversion results, we applied the method of space instead of time to collect soil samples of different desertification types. We tested the soil samples and analyzed them for soil wind erosion erodibility influencing factors, such as soil mechanical composition, soil organic matter content, soil crust factor, and vegetation factors. Results] The overall desertification of the Mu Us sandland tended to decline from 1986 to 2021, and the desertified land area shrank from 47 877.81 km² in 1986 to 45 914.06 km² in 2021 (a reversal rate of 56.11 km²/a). Desertification could be divided into three periods:1986-2001 was the desertification development period that exhibited decreasing trends for soil clay, silt, and organic matter content, and increasing trends for soil sand content, soil crust factor, and vegetation factors; 2001-2011 was the period of significant desertification reversal; and 2011-2021 was the desertification stabilization period. During the reversal period, the percentage content of soil clay, silt, and organic matter showed an increasing trend, and the soil sand grain percentage content, soil crust factor, and vegetation factors showed a decreasing trend. The greater the degree of reversal, the faster the rate of change of the factors. As desertification degree weakened, the percentage content of soil clay, silt, and organic matter showed a linear increasing trend, with increasing rates of 1.55%, 7.08% and 1.98%, respectively. The values of soil sand grain percentage, crust factor, and vegetation factors showed a linear decreasing trend, with decreasing rates of 8.62%, 0.13% and 0.23%, respectively. Conclusion] The reversal process of desertification in the Mu Us sandland caused soil structure to become finer, crusts to develop, vegetation to increase, and soil erosion resistance to increase, thereby significantly inhibiting wind erosion of soil.