旱区不同层状结构土壤的水分运移过程与模拟

针对位于干旱-半干旱气候带的我国西北部矿区生态修复过程中重构层状土壤水分运移规律不清等问题，通过设置不同层状结构土壤进行水分运移入渗试验，监测土壤剖面水分变化，采用Hydrus-1D模拟降雨入渗过程，从土壤水分、水势和水通量3个方面揭示层状土壤水分运移特征，并基于优化后的模型进行情景模拟，探究夹层特征对浅层土壤水分运移的影响。研究结果表明，夹层明显改变了土壤水分的分配与运移过程，土壤水势在夹层界面连续分布，而土壤水分在夹层界面发生突变；虽然黄土夹层和风化砂岩夹层都阻滞了土壤水分的下渗，但其阻滞原理不同，前者表现为黏质夹层渗透性能差导致夹层以上土壤水分滞留，后者归因于粗质夹层土壤基质势小造成水分持留在上部黏质土壤中；根据不同夹层属性的情景模拟结果，提出在风积沙40 cm深度处设置20 cm厚的黄土夹层有利于提高夹层以上土壤水分以供植被利用。研究探明了风积沙区充填黄土对土壤水分运动的影响，并为土壤类型以风积沙和黄土为主的我国西北部矿区在生态修复中的土壤重构方式提供了参考依据。

Water transport process and simulation of layered soils with different configurations in an arid region

The mining area in northwest China is located in the arid and semi-arid zone, in which the surface water resource is sparse and the ecological environment is fragile. Coupled with the exploitation of mineral resources, the land has been degraded seriously. How to realize the efficient reclamation of soil and the effective utilization of soil water is an urgent scientific and technical problem. In this study, the layered soil with different configurations is set up for water transport and infiltration test to monitor the moisture changes in the soil profile. Hydrus-1D is used to simulate the rainfall infiltration process and reveal the water transport characteristics of layered soil from three aspects: soil moisture, water potential and water flux. The scenario simulation is conducted based on the optimized model to explore the effect of interlayer characteristics on shallow soil water. The results show that the interlayer significantly changes the distribution and transport of soil water, and the soil water potential is continuously distributed at the interlayer interface, while the soil water abruptly changes at the interlayer interface. Although loess interlayer and weathered sandstone interlayer both block the infiltration of soil water, the principle and the source of water increase are different. The former is the retention of soil water above the interlayer due to