[AGE43-04] Relationship between Soil Thermal Conductivity and Electrical Conductivity at Room Temperatures
★Invited Papers
キーワード：Soil physics, Heat conduction, Electricity conduction
Soil thermal conductivity and electrical conductivity are both affected by soil texture, water content, bulk density , and pore-size distribution. However, there is a lack of understanding about the quantitative relationship between thermal conductivity and electrical conductivity, and limited datasets and models are available for describing the dynamics of electrical conductivity under field conditions. In this study, we show that soil thermal conductivity and electrical conductivity curves are interrelated and can be described with a unified series-parallel model. When normalized thermal conductivity and electrical conductivity values are plotted against the degree of saturation, a “mirror image” is observed between the two curves. Based on this phenomenon, a normalized electrical conductivity model is developed from the Lu et al. (2007) thermal conductivity model, which estimates electrical conductivity from measurements of soil texture, bulk density, and water content. Experimental examination on three soils indicates that the predicted electrical conductivity values agree well with measured data with RMSEs lower than 0.098 dS m-1, and bias from -0.080 to 0.011 dS m-1. The model has important implications in studying coupled processes of heat, water and nutrients in the field.