干密度和质量含水量对TDR法测量土壤体积含水量的影响

The Effect of Dry Density and Mass Moisture Content on Volumetric Water Content of TDR Measurement

试验采用TRIME-PIC032型TDR土壤水分计测量土壤体积含水量,由于该水分计测量土壤体积含水量时误差较大,因此使用之前需要对其进行标定。试验通过固定干密度以土样中水的质量分数为变量和固定土样中水的质量分数以干密度为变量的正交试验测得土样中水的体积分数,并以烘干法结果为标准对TDR进行标定。试验结果表明:对同一型号不同的TDR,在使用之前都应进行标定;相同土样中水的质量分数,干密度变化范围不大的情况下,干密度对TDR的影响可以忽略;相同干密度,土样中水的质量分数在8%~27%范围内,TDR测量误差总体上随土样中水的质量分数的增加呈现先增加而后减小的变化趋势,在土样中水的质量分数为19%时,测量误差达到最大。

The TRIME-PIC032 TDR soil moisture meter was used to measure the volumetric moisture content of the soil.Because the moisture meter used to measure the moisture content of the contaminated soil had a big measurement error,it was required to be calibrated before use.The volumetric moisture content of the soil sample was measured by the orthogonal test of the fixed dry density with water content as the variable and the fixed moisture content with the dry density as the variable,and the TDR was calibrated with the drying method result as the standard.The test results show that different TDRs of the same model should be calibrated before use.When the same water content and dry density do not vary greatly,In the case of the same dry density and different water content,the moisture content is in the range of 8%-27%.The TDR measurement error increases first and then decreases with the increase of soil moisture content.When the water content is 19%,the measurement error reaches the highest.