【摘要】 【目的】为解决干旱区风沙土结构松散、保水能力弱及易受水力侵蚀等突出问题，以我国典型风沙区风沙土为研究对象，探讨膨润土与棉花秸秆纤维复配对其物理性质的改良效果及其水土保持意义。【方法】将风沙土与不同比例的膨润土和棉花秸秆纤维混合，采用环刀法测定土壤密度、毛管持水量、总孔隙度和饱和含水量；通过干湿循环试验分析土壤的保水性能与结构稳定性，在干燥过程中每日称量监测水分保持动态，并于第1次和第2次干燥后测定土壤硬度；同时利用扫描电镜（SEM）对改良土壤的微观结构进行观察分析。【结果】1）在膨润土添加比例相同条件下，随着棉花秸秆纤维添加量的增加，土壤密度降低14.66%～17.62%，毛管持水量、总孔隙度和饱和含水量分别提高20.96%～24.59%、5%～8.01%和25.72%～27.50%。2）棉花秸秆纤维显著提升风沙土的保水能力，细棉花秸秆纤维对保水性能的改善效果优于粗棉花秸秆纤维，添加比例为1.2%与1.5%时保水能力最佳。3）膨润土通过增强土粒间胶结作用提高土壤结构稳定性，使土壤硬度提高476.13%；但在第2次干湿循环后，土壤硬度显著降低，最大降幅达84.16%。4）扫描电镜结果发现，膨润土可通过包裹风沙土颗粒并填充间隙增强其紧实度，而棉花秸秆纤维的添加可以通过桥接作用进一步优化结构。【结论】膨润土和棉花秸秆纤维复配可以改善风沙土物理结构，显著提升其保水性和抗侵蚀能力，具有良好的生态适用性和工程潜力，可为干旱区边坡稳定、水土保持及生态修复工程提供技术支撑和理论依据。更多还原

【Abstract】 [Objective] To address the prominent problems of loose structure, weak water-retention capacity, and high susceptibility to hydraulic erosion in aeolian sandy soils of arid regions, aeolian sandy soil from a typical sandy area in China was selected as the research object. This study investigates the enhancing effects of combined application of bentonite and cotton straw fiber on the physical properties of aeolian sandy soil and its significance for soil and water conservation.[Methods] Aeolian sandy soil was mixed with different proportions of bentonite and cotton straw fiber. Soil bulk density, capillary water-holding capacity, total porosity, and saturated water content were determined using the cutting ring method. Soil water-retention performance and structural stability were evaluated through dry–wet cycle tests, during which water-retention dynamics were monitored by daily weighing in the drying process, and soil hardness was measured after the first and second drying stages. In addition, the microstructure of the amended soil was examined by scanning electron microscopy(SEM). [Results] 1) Under the same bentonite application rate, soil bulk density decreased by 14.66%–17.62% with increasing cotton straw fiber content, while the capillary water-holding capacity, total porosity, and saturated water content increased by 20.96%–24.59%, 5.00%–8.01%, and25.72%–27.50%, respectively. 2) Cotton straw fiber significantly enhanced the water-retention capacity of aeolian sandy soil, with fine cotton straw fiber exhibiting a stronger enhancing effect than coarse ones. The optimal water-retention performance was achieved at addition rates of 1.2% and 1.5%.3) Bentonite improved soil structural stability by enhancing interparticle bonding, resulting in an increase in soil hardness of 476.13%. However, after the second dry–wet cycle, soil hardness decreased significantly, with a maximum reduction of 84.16%. 4) SEM observations revealed that bentonite enhanced soil compactness by coating aeolian sandy soil particles and filling interparticle pores, while the addition of cotton straw fiber further optimized the soil structure through a bridging effect.[Conclusions] The combined application of bentonite and cotton straw fiber effectively improves the physical structure of aeolian sandy soil and significantly enhances its water-retention and erosionresistance capacities. This composite amendment demonstrates good ecological applicability and engineering potential, providing technical support and theoretical basis for slope stabilization, soil and water conservation, and ecological restoration projects in arid regions.更多还原