土壤浸出液电导率测定的不确定度评定方法

The Evaluation Method of Measurement Uncertainty for Conductivity of Soil Extract

通过电导率仪对土壤浸出液中离子浓度的测定，本文提供了一个电导率测量不确定度的评定方法，并对测定过程中的注意事项作了讨论。土壤浸出液的电导率测量不确定度的主要来源是样品平行测定重复性、样品土壤浸出液的制备、电导率仪的校准结果、校正电导率仪的标准电导率溶液的制备等。对这些不确定度分量进行分析和合成，从而得到扩展不确定度值。以某农田的土壤浸出液为例，进行完整的电导率测量不确定度的评定，其结果为电导率平均值为114．5μS／cm，扩展不确定度值为5．5μS／cm。

An evaluation method of measurement uncertainty for soil conductivity was suggested using electrical conductivity meter to determine ion concentration in soil extract, and some matters needing attention in experimental process were discussed in this paper also. The major sources of measurement uncertainty have arisen from parallel determination repeatability for sample soil, preparation for soil extracts, indication error of an electrical conductivity meter past calibration, preparing standard solutions used for calibration of conductivity meter etc. These subcomponents then were analyzed and combined, so expanded uncertainty was obtained. On the basis of determined conductivity values of soil extract from a cropland soil we collected, the evaluation of conductivity was performed completely. Its average value was 114.5μS/cm and the expanded uncertainty was 3.5μS/cm