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| DOI：10.13522/j.cnki.ggps.2017.0326 |
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| Stability of Soil Aggregates in Riparian Zone of the Three Gorges Reservoir Studied Using the Le Bissonnais Method |
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LU Zhuchou, BAO Xinyi, LIU Xiao, ZHANG Hailing, XIANG Hanyu, JIA Guomei
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College of Biological and Pharmaceutical Sciences, Three Gorges Univiersity, Yichang 443002, China; Pall Corporation, 25 Harbor Dr, Port Washington, NY, U.S.A, 11050; Hubei International Scientific and Technological Cooperation Center of Ecological Conservation and Management in Three Gorges Area, China Three Gorges University, Yichang 443002, China
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| Abstract: |
| 【Objective】 The stability of soil aggregate is an important indicator of soil erosion. The objective of this paper is to understand the mechanisms underlying soil aggregate destruction in the riparian zone of the Three Gorges Reservoir due to water rising and falling, aimed to provide baselines to help improve soil stability and the ecosystem service of the region. 【Method】 We took soil samples from the riparian zone at Tongzhuang and measured the stability of their aggregates and soil erodibility using the fast wetting (FW) and the slow wetting(SW) in the Le Bissonnais method. The investigated locations included a site 145~155 m above sea level subjected to long water inundation, a site 155~165 m above sea level with moderate water inundation, and a site 165~175 m above sea level with least inundation. The control was samples taken from an adjacent site 175~185 m above sea level outside the riparian zone. 【Result】 The aggregates on the site 155~165 m above the sea level had biggest mean diameter, while the aggregates on the site 145~155 m above sea level had the smallest mean diameter, with those in the control and the site 165~175 m above sea level between. The value of the erodibility parameter was the highest on the latitude of 145~155 m and the lowest on the altitude 155~165 m. The aggregate diameter distribution depended on the measurement methods. Most aggregates measured using the FM method was less than 1 mm in diameter, while those measured using the SM method was less than 2 mm in diameter. 【Conclusion】 The results revealed that prolonged inundation by water reduced aggregate stability and increased soil erodibility, and short wetting-drying cycles due to rising and falling of the water level in the reservoir has a destructive impact on aggregate stability. |
| Key words: soil aggregates; Le Bissonnais method; Hydro-Fluctuating Belt of Three Gorges Reservoir; water stability |
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