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| DOI： |
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| Water Release Curves and Their Fitting for Soils in the Hills of the Three Gorges Reservoir |
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NIU Xiaotong , LIU Muxing, YI Jun, WU Siping， ZHANG Jun, YANG Yan
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College of Urban and Environmental Sciences, Central China Normal University, Wuhan 430079, China;.Key Laboratory for Geographical Process Analysis & Simulation of Hubei Province, Wuhan 430079, China
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| Abstract: |
| To unravel the mechanism of water holding capacity of soils and improve ecological system management in mountainous areas, we measured the water release curve of intact soil samples taken from Dalaoling and Yiling Mountainsin the Three Gorges of the Yangtze River. The soils examined included subalpine brown soil in temperate deciduous broad-leaved forest, mid-mountain yellow brown soil in the mixed broadleaf-conifer forest, soil intea garden, and low-mountain yellow soil in the warm coniferous forest. The water retention curves were measured using the centrifugation method. The results showed that with the increase in matric potential, the water content decreased quickly first and then gradually flattened. The waterholding capacity of the yellow soil in the warm coniferous forest was the lowest, and the yellow brown soil in the mixed broadleaf-conifer forest relative had the highest water holding capacity compared with other two woodland soils. The tea garden soils hold less water than the woodland soils. Pore-size analysis revealed that the number of large pores decreased with soil depth. All water release curves can be fitted to the van Genuchtenmodel with R2>0.95. The parameter n in the model was related to soil organic matter and silt, while parameters α was weaklyrelated to physical and chemical propertied of the soils. |
| Key words: mountain soil; soil water characteristic curve; model simulation; Three Gorges Reservoir Area |
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