Abstract:Dynamic information of soil water,temperature,thermal properties and other physical parameters is vital for de-scribing the physical,chemical,and biological processes in the vadose zone.Recent development of the thermo-Time Domain Reflectometry(Thermo-TDR) opens up an opportunity for such purposes.In this study,the Thermo-TDR technique is applied to simultaneously determine water content,electrical conductivity,heat capacity,thermal conductivity,and thermal diffusivity in soils of various textures.Soil bulk density,air-filled porosity,and degree of saturation are then obtained from the dependence of soil heat capacity on water content and bulk density.The results indicate that the Thermo-TDR measured soil water,electrical,and thermal properties,as well as other physical parameters,agree well with the results from theoretical models or gravimetric measurements.Further improvement in probe design,waveform interpretation,and determination of the effective probe length will increase the measurement accuracy of the Thermo-TDR technique.