Implications of soil resistivity measurement using the electrical resistivity method: A case study of a maize farm under different soil preparation modes at KNUST Agricultural Research Station, Kumasi

Continuous vertical electrical sounding (CVES) technique was used to investigate the soil moisture content of a maize farm at the Kwame Nkrumah University of Science and Technology (KNUST) Agricultural Research Station (ARS), Kumasi, Ghana. The soils of the maize farm were categorized into four different land preparation modes; ploughed-harrowed, ploughed, hoed and no-till plot. Time-lapse measurements with CVES was carried out using the multi-electrode Wenner array to investigate soil moisture variation with the help of the ABEM Terrameter SAS 4000 resistivity meter. The results showed a heterogeneous distribution of soil moisture content both spatially and temporally. Most of the water available for plants‘ uptake was within a depth of 0.20 – 0.40 m which coincided with the root zones of the maize crops. In addition, the no-till plot was found to conserve more moisture during dry weather conditions than the rest of the plots. The research shows that CVES technique is applicable in monitoring shallow soil water content in the field and the results obtained could be used to optimize irrigation scheduling and to assess the potential for variable-rate irrigation.