| 零盐分效应点: 与巴西São Paulo州典型土壤的粘土矿物结构之间的关系 |
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| 作者姓名： | M. E. ALVES A. LAVORENTI |
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| 作者单位： | Departamento de Física e Informática, Institute de Física de São Carlos-IFSC/USP, São Carlos (SP) 13560-970 (Brazil). E-mail: mealves@ifsc.usp.br;Departamento de Ciências Exatas, Escola Superior de Agricultura 'Luiz de Queiroz'-ESALQ/USP, Piracicaba (SP)13419-980 (Brazil) |
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| 基金项目： | Project supported by the State of Sāo Paulo Research Foundation-FAPESP, Brazil （No. 98/01502-8）. |
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| 摘 要： | The point of zero salt effect （PZSE） is the soil pH value at which the magnitude of the variable surface charges is not changed due to variations in the ionic concentration of the soil solution. This property influences not only electrochemical phenomena occurring at the solid-solution interface but also the flocculation degree of the soil particles. In this study we investigated the relationships between the clay mineralogy and the PZSE values of representative soils of the Sāo Paulo State, Brazil. The results confirmed the usefulness of the difference between the soil pH values measured in 1 mol L^-1 KCl （pHKCl） and in water （pHH2O） （2 pHKCl-pHH2O） for estimating the PZSE of tropical soils, except for the ones rich in exchangeable Al; furthermore, the ApH index （pHKC1 - pHH2O） was highly correlated with the difference between the PZSE and pHH2O values, reiterating the △pH utility for estimating both the signal and the magnitude of the net surface charge of tropical soils. Finally, correlation and multiple regression analyses showed that the PZSE value of weathered non-allophanic tropical soils tends to increase and to equal the soil pH due to the weathering-induced kaolinite destabilization and concomitant Fe- and Al-oxide accumulation.
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| 关 键 词： | PZSE 土壤 pH值 巴西 电化学 |
| 收稿时间： | 2005-05-16 |
| 修稿时间： | 2005-06-24 |
Point of zero salt effect: Relationships with clay mineralogy of representative soils of the São Paulo State, Brazil |
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| M. E. ALVES,A. LAVORENTI.Point of zero salt effect: Relationships with clay mineralogy of representative soils of the São Paulo State, Brazil[J].Pedosphere,2005,15(5):545-553. |
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| Authors: | M E ALVES and A LAVORENTI |
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| Institution: | Departamento de Física e Informática, Institute de Física de São Carlos-IFSC/USP, São Carlos (SP) 13560-970 (Brazil). E-mail: mealves@ifsc.usp.br;Departamento de Ciências Exatas, Escola Superior de Agricultura 'Luiz de Queiroz'-ESALQ/USP, Piracicaba (SP)13419-980 (Brazil) |
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| Abstract: | The point of zero salt effect (PZSE) is the soil pH value at which the magnitude of the variable surface charges is not changed due to variations in the ionic concentration of the soil solution. This property influences not only electrochemical phenomena occurring at the solid-solution interface but also the flocculation degree of the soil particles. In this study we investigated the relationships between the clay mineralogy and the PZSE values of representative soils of the São Paulo State, Brazil. The results confirmed the usefulness of the difference between the soil pH values measured in 1 mol L-1 KCl (pHKCl) and in water (pHH2O) (2 pHKCl-pHH2O) for estimating the PZSE of tropical soils, except for the ones rich in exchangeable Al; furthermore, the ΔPH index (pHKCl-pHH2O) was highly correlated with the difference between the PZSE and pHH2O values, reiterating the ΔPH utility for estimating both the signal and the magnitude of the net surface charge of tropical soils. Finally, correlation and multiple regression analyses showed that the PZSE value of weathered non-allophanic tropical soils tends to increase and to equal the soil pH due to the weathering-induced kaolinite destabilization and concomitant Fe- and Al-oxide accumulation. |
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| Keywords: | electrochemical properties iron oxides kaolinite tropical soils weathered soils |
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