土壤表面电荷测定的两种方法之比较

用返滴定法和Mehlich法研究测定了我国不同地带土壤 (砖红壤、红壤、黄棕壤、暗棕壤、黑土 )无机胶体的表面电荷。结果表明 :( 1 )两者的测定结果有较大的差异 ,其主要的原因是返滴定法和Mehlich法分别基于不同的衡量标准 ,从不同的侧面反映了土壤表面的电荷性质 ;( 2 )返滴定法与Mehlich法各有其优点 ,但在具体的测定过程中都有些环节可能需要改进。

COMPARISON OF TWO METHODS FOR DETERMINING SURFACE CHARGE OF INORGANIC SOIL COLLOIDS

Surface charge of inorganic colloids in soils(brick red soil, red soil, brown yellow soil, dark brown soil, black soil) distributed in different latitudes of China was studied with the back-titration method and Mehlich method. Results show that: (1)a big difference exists between the two methods, mainly because they are based on different measuring units, but anyway they reflect surface charge of inorganic colloids from different sides; and (2)either has its own advantages. When used for determination of surface charge of inorganic colloids, however, both of them have to be modified in terms of practical procedure in determination.