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用电导法测定土壤可溶盐分总量,是国内外广泛应用的一种快速、简便和比较准确的方法。有些国家直接用电导率作土壤盐渍程度的指标;全国第二次土壤普查亦要求以25℃的电导率为指标,划分盐渍化等级标准。由于我国沿用以土壤含盐百分数为指标,且目前还没有以电导率为指标的统一标准。为此,采用电导法测定后,仍常需将电导率换算成含盐百分数后使用。比较严格的方法是先测定一批对比数据,经统计处理,绘制回归曲线,再通过回归方程进行计算。但一条回归曲线若想保持其足够的精密度,往往只能在不大的范围内使用。因此,使用比例系数换算虽比较粗放,但简便易行,还是很有实用价值的。
It is a fast, simple and accurate method widely used at home and abroad to determine the total soluble salt content by conductivity method. In some countries, conductivity is used as an indicator of the degree of soil salinity. The second national soil survey also requires the conductivity of 25 ℃ as an index to classify the salinity levels. As China’s use of soil salt percentage as an indicator, and there is no uniform conductivity as an indicator of the standard. To this end, the use of conductivity measurement, it is often necessary to convert the conductivity percentage salt used. More stringent method is to measure a number of comparative data, the statistical processing, drawing regression curve, and then through the regression equation to calculate. However, a regression curve can only be used to a lesser extent if it is to maintain its sufficient precision. Therefore, the use of scale factor conversion is more extensive, but simple, still very practical value.