Investigation of Dielectric Properties of Sodic Soil at C Band Microwave Frequency

Abstract

Sodic soils represent one of the most critical forms of land degradation, significantly limiting agricultural productivity due to excessive exchangeable sodium, poor structural stability, restricted water infiltration, and nutrient imbalance. These soils exhibit high pH, low porosity, poor aggregation, and reduced microbial activity, making them difficult to manage through traditional soil assessment methods. As global food security increasingly depends on sustainable soil management, the need for rapid, accurate, and non-destructive soil characterization techniques has grown substantially. Microwave Remote Sensing (MRS), particularly at C-band frequencies (4 8 GHz), offers a promising approach to monitoring soil moisture, salinity, and structural conditions due to its all-weather capability, moderate penetration depth, and sensitivity to dielectric variations. The dielectric properties of soilrepresented mainly by real permittivity (and#949;and#8242;), dielectric loss (and#949;and#8243;), and loss tangent (tan and#948;)provide insight into its moisture content, salinity, and physical composition. However, limited research exists on the dielectric behaviour of sodic soils at C-band frequencies, where sodium-induced dispersion and low water retention significantly alter electromagnetic responses. newlineThis thesis aims to systematically investigate the dielectric properties of sodic soils at C-band microwave frequency and establish quantitative relationships between dielectric parameters and soil physical and chemical attributes. A total of 25 soil samples were collected from sodic regions across Maharashtra, selected based on geo-tagged sampling and spatial variability. Physical analyses included bulk density, porosity, water holding capacity, and textural classification (sand silt clay fractions). Chemical parameters such as pH, electrical conductivity, organic carbon, macronutrients (N, P, K), and micronutrients (Zn, Fe, Cu, Mn, S, B) were quantified to assess the extent of sodicity and its impact on soil behaviour.