title: Soil stability characteristics of mulberry lands at hydro-fluctuation belt in the Three Gorges Reservoir area, China.
abstract: The hydro-fluctuation belt in the Three Gorges Reservoir area is a typical seasonal and artificial wetland system and ecologically fragile zone. Using the widely existing mulberry forest lands in the hydro-fluctuation belt as an example and the 180-m water-level forest land as a control, this paper analyzes the soil stability of mulberry forestlands at different water levels in the hydro-fluctuation belt by analyzing and comparing the changes between soil physical and mechanical properties. The results indicated that (1) water-level changes, such as rising, flooding, draining, and exposure, affect the soil structure in mulberry forestlands. The soil agglomeration statuses for the soil layers decreased from 180 > 175 > 170 > 165 m, and the soil agglomeration statuses at a depth of 0∼20 cm decreased by 43.79, 44.95, and 57.45% compared with the control. (2) The soil water stability index decreased as follows: 180 > 170 > 175 > 165 m, which only accounted for 50.00, 47.73, and 40.91% of the control. In addition, the soil water stability indexes for the topsoils at various water levels were 1.87 (180 m), 1.67 (175 m), 2.92 (170 m), and 1.86 (165 m) times greater than those of the subsoils; thus, the resistance to hydraulic dispersion and disintegration were greater in the topsoil than in the subsoil. (3) The soil aggregate stability index decreased from 180 > 165 > 170 > 175 m and by 22.75, 23.53, and 35.29% compared with the control. (4) The soil shear strengths (composed of the cohesive force C and the internal friction angle φ) of the topsoils at water levels of 175, 170, and 165 m were significantly lower than in the control, and the internal friction angles decreased by 10.52, 19.08, and 43.25% and the cohesive force decreased by 9.88, 16.36, and 27.51%, respectively. The stability of the soil structure was greatly influenced by the soil clay content, soil organic matter content, and waterlogging duration. The study results could provide scientific support for soil and water conservation in the hydro-fluctuation belt and for biological filter construction in the Three Gorges Reservoir area to control the transport of sediment and non-point source pollutants.
authors.affiliation: College of Resources and Environment, Institute of Soil and Water Conservation and Eco-environment, Southwest University, Chongqing, 400715, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Jiang
authors.affiliation: College of Resources and Environment, Institute of Soil and Water Conservation and Eco-environment, Southwest University, Chongqing, 400715, China. shidm_1970@126.com.
authors.forename: Dongmei
authors.initials: D
authors.lastname: Shi
authors.affiliation: Department of Medical Technology, Chongqing Medical and Pharmaceutical College, Chongqing, 401331, China.
authors.forename: Xueqin
authors.initials: X
authors.lastname: Hu
authors.affiliation: Institute of Sericulture and Systems Biology, Southwest University, Chongqing, 400715, China.
authors.forename: Xianzhi
authors.initials: X
authors.lastname: Huang
authors.affiliation: College of Resources and Environment, Institute of Soil and Water Conservation and Eco-environment, Southwest University, Chongqing, 400715, China.
authors.forename: Yexin
authors.initials: Y
authors.lastname: Li
authors.affiliation: College of Resources and Environment, Institute of Soil and Water Conservation and Eco-environment, Southwest University, Chongqing, 400715, China.
authors.forename: Tianlei
authors.initials: T
authors.lastname: Guo
mesh_terms: D002681:China; D003247:Conservation of Natural Resources / Q000379:methods*; D004463:Ecology; D004784:Environmental Monitoring / Q000379:methods*; D055868:Floods; D031625:Morus / Q000254:growth & development*; D045483:Rivers / Q000737:chemistry*; D012987:Soil / Q000737:chemistry / Q000592:standards; D014881:Water Supply
chemical_list: D012987:Soil
keywords: Aggregation stability; Hydro-fluctuation belt; Mulberry land; Soil shear strength; Three Gorges Reservoir area; Water level