土壤含盐量对TDR含水率测试结果的影响及校正方法

利用多种TDR仪器测试不同盐分质量浓度条件下的含水率,与烘干法测得的结果进行比较,探讨了土壤盐分对各种TDR仪器的测量精度的影响。针对TDR100仪器,采用多种探头,分析不同长度、不同间距的探针对测试结果的影响。结果表明,所选5种仪器测试结果均受盐分影响,随盐分质量浓度的增加,测得的含水率值增大或是无法得出合理数值。TDR100所用探头,其探针越长、间距越宽受盐分影响越大。在含盐率较低的土体中,各仪器测试结果与烘干法测量结果变化趋势基本一致,可采用线性函数进行标定,R2均在0.94以上。试验结果可为野外试验的选点、测试和含水率校正提供参考。

The Impact of Soil Salinity on Measurement of Water Content by Using TDR and the Calibration Method

Five TDR instruments were used to measure soil water content under different soil salinity and compared with oven drying measurement.It is shown that soil salinity has significant affect on the measurement accuracy from different TDR instruments.The TDR100 measurement with different of probe length and spacing indicated that the water content measurement increases with increasing soil salinity and even a reasonable value could not come out for high soil salinity and water content.In the lower salinity,the measurement results of various instruments have a consistent trend with the oven drying measurements,and linear function could be used to calibrate the result with R2 above 0.94.