| 三峡库区坡地表层风化特征研究 |
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| 作者姓名： | JIANG Hong-Tao XU Fei-Fei CAI Yi YANG Da-Yuan |
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| 作者单位： | [1]Department of Natural Resource Sciences, College of Natural Resource and Environmental Sciences, Zhejiang University,Huajiachi Campus, Hangzhou 310029 （China）. [2]University of Florida, Institute of Food and Agricultural Sciences, Indian River Research and Education Center, Fort Pierce, FL 34945-3138 （USA） |
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| 基金项目： | Project partly supported by the U.S. Environmental Protection Agency through a contract with the Nonpoint Source Management/Water Quality Standard Section of the Florida Department of Environmental Protection （No. WM746）. |
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| 摘 要： | Extractability and mobility of Cu and Zn and their relationships with 1） accumulation of Cu and Zn and 2） soil pH were studied in three sandy soils （Wabasso, Ankona, and Winder） from commercial citrus groves in Florida, USA. The soils, with a broad range of Cu and Zn concentrations, were fractionated by a modified procedure of Amacher, while Cu and Zn mobility were evaluated using column leaching. The extractability of Cu and Zn increased with decreasing soil pH. Also with increasing total soil Cu and Zn for extractable Cu in the Wabasso sand a threshold level, where the metal extraction rate increased, was noted at 100 mg kg^-1, whereas for extractable Zn in the Wabasso sand the threshold level was found at 60 mg kg^-1 and in the Ankona sand at 120 mg kg^-1. These results suggested that the release potential of Cu and Zn was greater in the Wabasso sand than in the Ankona sand. The column leaching experiment showed that at total soil Cu or Zn concentrations 〈 100 mg kg^-1 all leachates had low Cu and Zn concentrations. However at total concentrations 〉 200 mg kg^-1 for Cu and 〉 150 mg kg^-1 for Zn with decreasing soil pH, the concentrations of both Cu and Zn in the leachates increased exponentially. Also in these sandy soils soluble Cu and Zn mainly originated from the exchangeable fractions, and pH was a key factor controlling Cu and Zn extractability and mobility.
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| 关 键 词： | 砂土 萃取行为 迁移行为 铜 锌 |
| 收稿时间： | 2005-04-25 |
| 修稿时间： | 2005-08-29 |
Weathering characteristics of sloping fields in the Three Gorges Reservoir area, China |
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| JIANG Hong-Tao,XU Fei-Fei,CAI Yi,YANG Da-Yuan.Weathering characteristics of sloping fields in the Three Gorges Reservoir area, China[J].Pedosphere,2006,16(1):50-55. |
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| Authors: | JIANG Hong-Tao XU Fei-Fei CAI Yi and YANG Da-Yuan |
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| Institution: | Department of Urban and Resources Science, Nanjing University, Nanjing 210093 (China). E-mail: hongtaojiang@sina.com.cn;Department of Urban and Resources Science, Nanjing University, Nanjing 210093 (China). E-mail: hongtaojiang@sina.com.cn;Department of Earth Science, Nanjing University, Nanjing 210093 (China);Department of Urban and Resources Science, Nanjing University, Nanjing 210093 (China). E-mail: hongtaojiang@sina.com.cn |
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| Abstract: | For the purpose of understanding the weathering characteristics of surface layers in purple mudstone sloping fields of the Three Gorges Reservoir area of China, oxide content of major elements, composition of clay minerals, magnetic susceptibility, and difference in weathering characteristics of surface layers under different slope gradients were determined. The results showed that the oxide content of Si, Al, and Fe ranged from 60% to 75% and the weathering coefficient with depth showed no trend along the slope gradient. Also, for gentle (10° and 15°) and intermediate (25° and 40°) slopes the clay relative diffraction peak for kaolinite at the surface between 0-10 cm and 10-20 cm declined with an increase in slope gradient, while the relative diffraction peak for kaolinite in weathered layers on steep slopes (50° and 60°) disappeared altogether. Magnetic susceptibility decreased with increasing depth and, for a given depth layer, decreased with an increase in slope gradient. Analysis of the oxide content, weathering coefficients, clay minerals, and magnetic susceptibility showed that in the Three Gorges Reservoir area, the pedogenesis of the weathering layer in purple mudstone sloping fields was weak with weaker soil formation going from gentle slope to steep slope. |
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| Keywords: | copper extractability mobility water quality zinc |
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