[1]ZHANG Shujuan,HE Xiubin,BAO Yuhai,et al.Change Characteristics of Soil Aggregates at Different Water Levels in the Water-Level Fluctuation Zone of the Three Gorges Reservoir[J].Research of Soil and Water Conservation,2021,28(01):25-30.
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Research of Soil and Water Conservation[ISSN 1005-3409/CN 61-1272/P] Volume:
28
Number of periods:
2021 01
Page number:
25-30
Column:
Public date:
2021-01-10
- Title:
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Change Characteristics of Soil Aggregates at Different Water Levels in the Water-Level Fluctuation Zone of the Three Gorges Reservoir
- Author(s):
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ZHANG Shujuan1,2, HE Xiubin1, BAO Yuhai1, TANG Qiang
1
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(1.Key Laboratory of Mountain Surface Processes 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)
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- Keywords:
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soil aggregate; stability; water level; water-level fluctuation zone; Three Gorges Reservoir
- CLC:
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S152.4
- DOI:
-
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- Abstract:
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In order to study the effects of the periodic water-level fluctuation on soil aggregate composition and stability in the Three Gorges Reservoir, the topsoil samples were collected at different water levels of 150 m, 155 m, 160 m, 165 m, 170 m and 175 m in the water-level fluctuation zone and at the elevation of 180 m from the bank uplands where soil was used as a control since it was not subjected to inundation. The present study used dry and wet sieving methods to analyze the composition and stability of soil aggregate. The results showed that:(1)the content of >0.25 mm air-dried aggregates and water-stable aggregates at seven water levels accounted for more than 95% and 63.60%, respectively; the content of >5 mm air-dried aggregates and water-stable aggregates significantly decreased with the decrease of water levels, and the maximum reductions were 19.71% and 85.20%, respectively; the content of <0.25 mm air-dried aggregates and water-stable aggregates significantly increased with the decrease of water levels, and the maximum increases were 289.97% and 402.97%, respectively;(2)the content of >0.25 mm water-stable aggregates decreased significantly with the decrease of water levels, decreasing gradually from 92.75% of 180 m to 63.60% of 150 m; mean weight diameter and geometric mean diameter decreased significantly with the decrease of water levels, and the decreased ranges were 3.31%~66.43% and 5.81%~81.35%, respectively; fractal dimension was between 2.41~2.73, which increased with the decrease of water levels; compared with soil at 180 m, the percentage of aggregate destruction in the water-level fluctuation zone increased by 4.73%, 24.49%, 54.22%, 78.55%, 169.26% and 463.51% with the decrease of water levels, respectively;(3)the aggregate stability indexes were significantly or extremely significantly related to soil particle composition, bulk density, and soil organic carbon; >0.25 mm water-stable aggregate content, mean weight diameter, and geometric mean diameter had the significantly positive correlation with soil organic carbon, while fractal dimension and the percentage of aggregate destruction were significantly negatively correlated with organic carbon. It can thus be deduced that the periodic water-level fluctuation of the Three Gorges Reservoir significantly changed aggregate composition and stability. With the decrease of water levels, soil aggregate stability decreased significantly. This research can provide a basis for the study of soil erosion in the water-level fluctuation zone of the Three Gorges Reservoir.