【摘要】 为探究雨滴击溅对表层土壤结构和入渗特征的影响，揭示土壤微结构与入渗间的深层关联，以黄土高原(土娄)土为对象，采用模拟降雨、同步辐射CT扫描和入渗试验，系统地分析了不同雨滴击溅作用下土壤结构变化与入渗速率间的关系。结果表明：(1)击溅土壤结构发生变化，团聚体数量和三维分形维数显著增加，孔隙体积和大孔隙率显著减小。雨滴直径越大，击溅后的团聚体破碎程度越强，孔隙堵塞率最高达46.40%。(2)雨滴击溅下，破碎的团聚体堵塞孔隙，在土壤表层形成致密低渗的结皮层，结皮强度随雨滴直径和击溅次数的增加逐渐增加。(3)土壤入渗速率随雨滴直径和击溅次数的增加逐渐减小，经过3次雨滴击溅后减渗效应最高可达91.81%。(4)土壤稳渗速率与雨滴直径和土壤结构特征参数呈显著指数关系变化。研究表明，雨滴直径显著影响表层土壤结构和入渗特征，雨滴直径越大，土壤结构越分散，土壤入渗能力越低。更多还原

【Abstract】 In order to investigate the effect of raindrop splash on the topsoil structure and its infiltration characteristics, and to reveal the deep relationship between soil microstructure and infiltration, simulated rainfall, synchrotron radiation CT scanning and infiltration tests were used to analyse the relationship between the soil structure and infiltration capacity of Lou soil on the Loess Plateau under different raindrop splashing conditions. The results show that:(1) The structure of the disturbed soil was altered, and the number of aggregates and the three-dimensional fractal dimension degree were significantly increased. At the same time, the pore volume and macro-porosity were significantly reduced. The larger the diameter of raindrop, the stronger the degree of fragmentation and the pore clogging rate reached as high as 46.40%;(2) Under the splash of raindrops, the broken aggregates blocked the pores, and thus a dense and low permeable crust was formed on the topsoil, the crust strength increased with the increase of raindrop diameter and splash frequencies;(3) With increasing splash frequencies and raindrop diameters, the infiltration rate decreased gradually. Three splashes later, the infiltration reduction effect reached 91.81%;(4) The steady infiltration rate changed significantly and exponentially with the raindrop′s diameter and soil structure parameters. The results showed that the raindrop diameter significantly affected the topsoil structure and infiltration characteristics. The larger the raindrop diameter was, the more dispersed the soil structure was, and the lower the infiltration capacity of soil was.更多还原