Integration of electrical resistivity and soil analysis for Agricultural soil characterization—a case study

Abstract

Integration of 2D electrical resistivity method and soil analysis was used to characterize the topsoil in the farmland of Federal University Oye-Ekiti, Nigeria, to determine its suitability for agricultural purposes. A 2D electrical resistivity survey was carried out along four traverses using Wenner array electrode configuration with electrode spacing ranging from 1 to 5 m and station interval of 1 m. The acquired 2D electrical resistivity data were processed and inverted using DIPRO version 4.01 software. Forty (40) soil samples were collected along the established traverses at depth intervals of 0.5 and 1.0 m to estimate the moisture contents and grain size distributions. The 2D inverted resistivity sections revealed three probable geologic materials namely clay, clayey sand, and sand. Grain size analysis showed that the farmland is made up of gravel, sand, and fines (silts and clay) with mean percentage distributions of 8.77%, 80.08%, and 11.15% respectively. The moisture content of the forty (40) soil samples analyzed ranges from 10.2 to 18.6%, with an average value of 11.91%. Areas of low electrical resistivity values were observed to coincide with zones of fine particles and high moisture content and are identified to be favorable for crops in the farmland. This study shows the effectiveness of the electrical resistivity method and soil analysis in determining the variability of soil moisture content at shallow depth and in selecting soil that can aid the optimum production of crops.