Multi-Frequency Microwave Dielectric Characterization of Agricultural Soils for Precision Agriculture Applications

Soil quality plays a vital role in sustainable agriculture and crop productivity. This study evaluated the physical, chemical, and microwave dielectric properties of twenty agricultural soil samples collected from Mantha and Ghansawangi talukas of Jalna district, Maharashtra, India. Physical and chemical properties were determined using standard laboratory methods, while dielectric measurements were performed at C band (4.785 GHz), J band (7.60 GHz), and X band (9.685 GHz) using the two-point transcendental waveguide method. The soils were predominantly classified as clay loam, loam, and sandy loam with slightly alkaline pH (7.60–8.40) and non-saline conditions. The dielectric constant decreased with increasing frequency, ranging from 4.04–4.67 at C band to 2.70–3.15 at X band, while dielectric loss varied between 0.28 and 1.66 across the investigated bands. Correlation analysis revealed that moisture content, clay fraction, bulk density, and nutrient status significantly influenced the dielectric response. The findings demonstrate that microwave dielectric techniques provide a rapid, reliable, and non-destructive approach for soil quality assessment and have significant potential for precision agriculture and sustainable land management.