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用采自广东省徐闻县的一个铁铝土剖面研究了不同层次土壤的表面电荷特征及电荷的可变性。结果表明,该剖面C层以下土壤的CEC小于88 mmol kg-1,土壤游离氧化铁在140.9~220.3 g kg-1之间,为典型可变电荷土壤。土壤表面正电荷的数量及pH改变一个单位时表面正电荷的变化量均随土壤游离氧化铁含量的增加而增加。当pH<4.0时,土壤氧化铁对表面负电荷的贡献很小;但有机质的增加会使这一pH范围内土壤表面负电荷的可变性增加。该剖面土壤的PZSE高于PZNC,但两者均随土壤游离氧化铁含量的增加而增大。
The surface charge characteristics and charge variability of soils at different soil layers were studied using a ferroferric profile collected from Xuwen County, Guangdong Province. The results showed that the CEC of soils below C level in the profile was less than 88 mmol kg-1 and that of soil free iron oxide was between 140.9 and 220.3 g kg-1, which was a typical variable charge soil. The amount of positive charge on the soil surface and the change of the positive charge on the surface when the pH is changed by one unit all increase with the content of free iron oxide in the soil. At pH <4.0, soil iron oxide contributes little to the negative charge on the surface; however, an increase in organic matter increases the variability of negative charge on the soil surface in this pH range. The PZSE of soil in this section is higher than that of PZNC, but both of them increase with the content of free iron oxide in the soil.