Influence of Dielectric Relaxations of Soil Water on the Temperature Dependence of Soil Permittivity

Using a generalized refractive mixture dielectric model, the influence of the relative permittivity spectra of bound and unbound water in mineral soil on the nature of the temperature dependence of the relative permittivity of natural mineral soil, with a clay fraction content of 41.3%, was studied in the electromagnetic field frequency range from 50 MHz to 15 GHz. The causes of the emergence of intersections in the relative permittivity spectra of mineral soil, obtained at different temperatures but for a sample of the same moisture content, have been studied. It has been proved that the emergence of such an intersection point in the frequency range up to 1.5 GHz is due to the Maxwell–Wagner effect in bound water. The dependences of the frequency of the intersection point of the relative permittivity spectra of mineral soil on the temperature and volumetric content of bound and unbound water have been studied.