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| Experimental and simulation study on water infiltration characteristics of layered red soil |
| TU Anguo1,2, NIE Xiaofei1,3, LI Ying1,2, LI Hongren1,2* |
| 1. Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention, Nanchang, Jiangxi 330029, China; 2. Jiangxi Institute of Soil and Water Conservation, Nanchang, Jiangxi 330029, China; 3. Research Center of Soil and Water Conservation and Ecological Environment, Chinese Academy of Sciences and Ministry of Education, Yangling, Shaanxi 712100, China |
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Abstract Analyzing the effect of soil structure on soil water transport is an important basis for improving soil water use efficiency and controlling non-point source pollution. In this paper, homogeneous soil with bulk density of 1.35 g/cm3 and 1.55 g/cm3 and its upper and lower tight layered soil structure are taken as the research objects to studied. The method of combining constant head water infiltration experiment by indoor soil columns and model simulation was used to analyze soil water infiltration process and water redistribution characteristics under different layer structure. The results show that the infiltration process of layered soil with soft top and dense bottom can be divided into upper infiltration stage and lower infiltration stage. Compared with homogeneous soil, the infiltration rate of the upper layer is reduced slightly and the initial rate of the lower layer is increases for layered soil, but has little effect on the stable infiltration rate of the lower layer. The layered soil can significantly improve the water content of the upper layer, and the water redistribution process has changed at the discontinuous mutation that occurs at the interface. When the HYDRUS-1D model is used to simulate soil moisture redistribution in the layered soil, the direct combination of homogeneous soil hydraulic parameters has poor simulation effect. If a satisfactory simulation result is needed, the parameters of the intake suction must be optimized. The research results can provide theoretical support for soil water management and pollution control in red soil areas.
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Received: 20 April 2020
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