Electrical Geophysical method and GIS in Agricultural Crop Productivity in a Typical Sedimentary Environment

Abstract

ABSTRACT Accurate information about soil properties is required in plant growth and yield. Hence, the rising knowledge in the preservation of favourable soil properties is basically driven by its vital role in agricultural crop productivity. Electrical Resistivity Tomography (ERT) and GIS were used for site selection, soil suitability for agricultural use and topographical effect on soil properties distribution in Ambrose Alli University. Twelve traverses were conducted across the study area using Wenner array configuration. The least-square inversion method was adopted for the inversion model using RES2Dinver. Seven soil samples were collected from the selected site for soil test and grain analysis using IS standard in order to validate the ERT results. The results of the ERT gave resistivity signatures in the form of colour variations that depict the organic matter and mineral constituents of the soil. Soil in the valley side of the study area showed low resistivity signatures < 100 Ωm, slopy portion ranged from 100 to 600 Ωm, and soil at the top of the slope has resistivity values > 600 Ωm. GIS results generally classified spatial distribution of soil parameters across the area. Soil with low resistivity values < 100 Ωm has Organic Matter (OM): 4.27–4.80 %, Phosphorus (P): 50.23–54.22 mg/kg, Potassium (K): 290.0–340.0 cmol/kg, Total Nitrogen (TN): 62.20–65.11%, and pH: 6.8 to 6.9. Soil with resistivity values ranging from 100 to 600 Ωm has OM: 2.21–2.75%, P: 30.14–34.00 mg/kg, K: 100.2–107.2 cmol/kg, TN: 54.00–59.20%, and pH: 6.7–6.8. Soil with resistivity values > 600 Ωm showed lowest value ranges for OM: 0.51–0.61%, P: 10.20–15.20 cmol/kg, K: 37.20–40.20 mg/kg, TN: 10.20–15.20 %, and pH: 7.0 − 7.2. This study has shown that the study area with resistivity values < 100 Ωm would be most appropriate for high agricultural productivity as well as soil management.