墨黑土和氧化土一类土壤的表面电荷,随土壤溶液的pH和离子浓度而有较大的变化,故称为可变电荷。这些土壤中的可变电荷,是来自腐殖质、铁、铝、硅等的氧化物,氢氧化物以及非晶质铝硅酸盐等。另外,直到最近才从分子水平上明确了各物质电荷发生的机制及电荷的数量如何依赖于pH和离子浓度。但是,土壤是这些带可变电荷物质和带有永久电荷的层状硅酸盐矿物的混合物。为了研究土壤的可变电荷特性,分别测定可变和永久电荷是必要的。另外,从土壤“表观盐基吸收”现象,看不出各纯粹的可变电荷物质的性质。在本项研究中试图解决这类土壤 Soil black soil and oxide soil surface charge, with the soil solution pH and ion concentration and have a greater change, it is called variable charge. The variable charge in these soils is oxides, hydroxides and amorphous aluminosilicates from humus, iron, aluminum, silicon and the like. In addition, until recently it was clear at the molecular level how the charge-generating mechanism of each species and the amount of charge depend on pH and ion concentration. However, the soil is a mixture of these with a variable charge and a permanently charged phyllosilicate mineral. In order to study the variable charge characteristics of the soil, it is necessary to separately determine the variable and permanent charges. In addition, from the soil “apparent salt base absorption ” phenomenon, can not see the nature of the pure variable charge material. In this study we tried to solve this kind of soil