Estimation of Dielectric Properties of Clay Loam and Silty Soil With Different Salinity Levels Over Low Frequency Range

The dielectric properties of clay loam and silty soil moistened with various proportions of distilled water and saline solutions over the frequency range from 20 Hz to 2 MHz were estimated. It was observed that the dielectric constant ε ′ and dielectric loss ε ″ increased with increase in volumetric moisture content in the soils. Frequency-dependent dielectric constant ε ′ and dielectric loss ε ″ were found to decrease rapidly with increase in frequency. For moist soils, the dielectric loss increased more rapidly with increase in salinity compared to the corresponding dielectric constant. The complex impedance Z* (= Z ′–JZ ″) was also calculated from the measured values of ε ′ and ε ″ for the soils. The complex impedance plots (Z″ against Z ′) for clay loamy and silty soils with moisture content of distilled water and saline water solutions revealed that bulk resistance of the soil decreased with increase in salinity in the wet soil, indicating an increase in conductivity of the soil.