Dielectric Properties of Sodic Soils at C-Band: Analysis of Permittivity, Loss Tangent, and Conductivity

Abstract

This study investigates the dielectric properties of sodic soils at C-band microwave frequency using laboratory-based measurements on samples collected from ten locations in Maharashtra, India. Dielectric parameters including the real (ε′) and imaginary (ε″) parts of permittivity, conductivity (σ), resistivity (ρ), loss tangent (tan δ), and penetration depth (δp) were analyzed. Results showed that ε′ ranged from 3.30 to 4.18 and ε″ from 0.49 to 1.08, influenced by soil texture, moisture, and sodium concentration. Higher dielectric loss and lower δp were observed in crusted and compact soils, while granular soils exhibited deeper wave penetration and lower energy dissipation. The study revealed strong inverse relationships between conductivity and resistivity, consistent with existing models. Findings were compared with established dielectric models and remote sensing studies, confirming the relevance of C-band SAR for soil salinity monitoring. This work provides valuable baseline data for enhancing microwave remote sensing algorithms in sodic and semi-arid landscapes.