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.