Investigating the Impact of Water and Sand on Resistivity and Dielectric Constant of Soil

Abstract

The variation in resistivity, volumetric water content, dielectric constants, and pH has been measured with the addition of water for two agricultural soil samples. Also, the effect of increasing percentage and size of sand on resistivity, dielectric constant, pH, porosity, and bulk density has been recorded for a soil sample by a series of experiments in the laboratory.  The resistivity was measured with an indigenously developed two-probe resistivity meter, and the volumetric water content by a wet sensor. From the knowledge of volumetric water content, the dielectric constants were estimated. The results show that the initial resistivity of soils decreases sharply and then becomes constant with the addition of water content. Optimum soil conditions for crop growth were identified with 10-20% sand content and 50% porosity, exhibiting higher water holding capacity. The series of sand texture experimental results indicates that the higher the percentage and size of sand in soil, the lower the water content, and the higher the resistivity. The findings are significant for precision agriculture, irrigation development, and soil health assessment, as resistivity and dielectric properties can serve as rapid, non-destructive indicators of soil moisture and texture. The study highlights the potential of electrical measurements for improving soil management practices, improving water use efficiency, and supporting sustainable agricultural productivity.