乙酸铵交换法测定土壤中阳离子交换量不确定度评价

Evaluation of uncertainty in determining soil cation exchange capacity by ammonium exchange method

对乙酸铵交换法测定土壤中的阳离子交换量进行了不确定度评价,并对测量过程中的不确定度来源进行了分析量化。结果表明,不确定度来源于样品前处理、硼砂标准溶液及标定过程和空白滴定、样品滴定、风干土换算成烘干土的水分换算系数和样品重复测定过程,其中,硼砂标准溶液及标定过程引入的不确定度所占比例较大。

The uncertainty in determining soil cation exchange capacity by ammonium exchange method is evaluated,and the uncertainty sources in the whole determining process are analyzed and quantified in details.The results show that the uncertainty comes from the procedures of samples pretreatment,sodium tetraborate standard solution and calibration,blank titration,sample titration,conversion coefficient of air-dried soil converted into oven-dried soil,repetitive titration.Thereinto,the procedure of sodium tetraborate standard solution and calibration cover a comparatively great proportion.