TDR测定不同湿度土壤含水量的精度比较研究

目的]探讨TDR测定土壤含水量的原理,找出TDR测量土壤含水量的适合范围.方法]用波兰TDR/MUX/mpts水分测定仪,对不同湿度土样的体积含水量进行测定,同时用烘干法和环刀法分别测量其质量含水量和容重,然后转化成体积含水量与TDR的测量值进行比较.结果]对于质量含水量为0～5％之间的干燥土壤和质量含水量为22％以上的湿润土壤,TDR的测量精度较低.与烘干法相比,绝对误差均大于2％,相对误差大于10％.对于质量含水量为5％ ～22％之间的土壤,TDR的测量精度较高.结论]在湿润或半湿润地区,TDR法测量土壤体积含水量有较高的精度.

A Comparative Study of Soil Moisture Measurement Accuracy under Different Humidity Using TDR

Objective] The research aimed to study the principle of TDR measurement of soil moisture,and find out the suitable range of the determination of soil moisture.Method] With Poland TDR/MUX/mpts moisture analyzer,the volumetric water content of soil samples was measured under different humidity in Yichang.With the drying method and the ring knife method,the quality of the soil water content and dry density of the same soil samples were measured respectively,then transferred into a volumetric water content and compared with the accuracy of the results using TDR.Result] For dry soil whose quality of the soil water content was 0-5％ and humid soil whose quality of the soil water content was above 22％,TDR measurement precision was low.Compared with the drying method,the absolute error was greater than 2％,and the relative error was greater than 10％.For the soil whose quality of the soil water content was 5％-22％,TDR measurement precision was high.Conclusion] At moist or semihumid area,the determination of soil volumetric water content with TDR method had a higher precision.