The Study Of Dielectric And Emissivity Measurement Of Alkaline Soil At Microwave Frequency

Abstract

This work presents an analysis of the dielectric and emissivity characteristics of different soils under different moisture conditions, and its impact on plant-soil interactions and for the monitoring of soils by active and passive microwave fields. Soil samples were collected from Jalna district, Maharashtra, India, and characterized physicochemically (pH, EC, organic carbon, and macronutrients N, P, K) as well as electrically based on complex dielectric permittivity for the microwave frequency range of C-, J-, and X-bands. Measurements were conducted in TE10 mode on a waveguide bench and two-point method was employed for extracting the real (ε’) and the imaginary (ε″) permittivity, and subsequently the emissivities for the horizontal and vertical polarization for incidence angles ranging from 0° to 90° were calculated using Fresnel equations. It was found that ε’ decreases with increasing frequency, while ε” is greatly affected by ionic content and moisture. The polarization dependence on emissivity trends was correlated with EC and pH. The results present essential dielectric data for alkalinized soils, which has important implications for better soil moisture estimation, satellite calibration and sustainable land management practice in semi-humid climates.