Vol15 No.10: 2192-2206
【Title】Effects of seasonal water-level fluctuation on soil pore structure in the Three Gorges Reservoir, China
【Author】ZHANG Shu-juan1,2; TANG Qiang1,3; BAO Yu-hai1; HE Xiu-bin1*; TIAN Feng-xia1; LÜ Fa-you1; WANG Ming-feng1,2; Raheel ANJUM
【Addresses】1 Key Laboratory of Mountain Surface Process and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China; 2 University of Chinese Academy of Sciences, Beijing 100049, China; 3 Sustainable Agriculture Sciences Department, Rothamsted Research, North Wyke, Okehampton, Devon, EX20 2SB, UK; 4 Abdul Wali Khan University, Mardan 23200, Pakistan
【Corresponding author】HE Xiu-bin
【Citation】Zhang SJ, Tang Q, Bao YH, et al. (2018) Effects of seasonal water-level fluctuation on soil pore structure in the Three Gorges Reservoir, China. Journal of Mountain Science 15(10). https://doi.org/10.1007/s11629-018-5013-3
【Abstract】Inundation of the Three Gorges Reservoir has created a 30-m water-level fluctuation zone with seasonal hydrological alternations of submergence and exposure, which may greatly affect soil properties and bank stability. The aim of this study was to investigate the response of soil pore structure to seasonal water-level fluctuation in the reservoir, and particularly, the hydrological change of wetting and drying cycles. Soil pore structure was visualized with industrialX-ray computed tomography and digital image analysis techniques. The results showed that soil total porosity (˃ 100 mm), total pore number, total throat number, and mean throat surface area increased significantly under wetting and drying cycles. Soil porosity, pore number and throat number within each size class increased in the course of wetting and drying cycles. The coordination number, degree of anisotropy and fractal dimension were indicating an increase. In contrast, the mean shape factor, pore-throat ratio, and Euler-Poincaré number decreased due to wetting and drying cycles. These illustrated that the wetting and drying cycles made soil pore structure become more porous, continuous, heterogeneous and complex. It can thus be deduced that the water-level fluctuation would modify soil porosity, pore size distribution, and pore morphology in the Three Gorges Reservoir, which may have profound implications for soil processes, soil functions, and bank stability.
【Keywords】Soil pore structure; X-ray computed tomography; Image analysis; Wetting and drying cycles; Water-level fluctuation; Three Gorges Reservoir