Abstract:

The formation of the temperature field in the soil and the realization of heat transfer are related to  the change of the thermal properties of the soils. Thermal properties vary depending on climate factors  and soil properties. In this study, regression models were created between the thermal properties of  soils such as volumetric heat capacity, thermal diffusivity and thermal conductivity coefficients and  some physical and chemical soil properties (EC, OM, Clay, Silt, Sand, Db, θ ) that could be determined  more easily experimentally. The statistical significance level (p = 0.001) and regression coefficient (R2 =  0.76) of the regression model made between the volumetric heat capacity of soils and the properties  of EC, OM, Clay, Silt, Sand and Db were determined to be high. Adding volumetric moisture content  (θ ) to independent variables increased the performance of the models (R2 = 0.77-0.99) the statistical  significance level (p = 0.000) and the regression coefficient of the regression model including θ, EC,  OM, Clay, Silt, Sand, Db properties were found to be very high. The thermal diffusion coefficient of soils  and the regression models between EC, OM, Clay, Sand, Silt, Db, θ properties were determined as R2 =  0.76 and 0.79 (p = 0.000 and 0.002). The expression of regression models with polynomials including  the square, square root and product of soil properties increased the performance of the models the  model including Clay, θ, Clay2, θ, √OM , (EC·Db), √Clay , OM, OM2, Db soil properties showed high  level of statistical significance (p = 0.001) and was characterized by a higher regression coefficient (R2 =  0.90). The performance of the regression model between the thermal conductivity coefficient and Clay,  Silt, Sand, Db, θ soil properties is high (R2 = 0.71 p = 0.001) the performance of the model among the  parameters θ, Sand, Clay, Silt, Db, EC2, OM2, Db2, θ2 , EC, √OM, was determined to be very high (R2  = 0.91 p = 0.012). It seems possible that the regression models obtained can be applied in estimating  the thermal properties of soils.

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