Estimation of soil petrophysical parameters based on electrical resistivity values obtained from lab and in-field measurements

Abstract

Knowledge of soil petrophysical parameters is very useful for agricultural and environmental impact analysis. Therefore, it is important to develop techniques and methodologies to help obtain soil petrophysical maps both quickly and inexpensively. This paper shows two techniques for estimating clay content, porosity and cation exchange capacity from electrical measurements. The first one, based on soil resistivity measurements (SRM), is performed in the laboratory. The second technique, ERT&WRM, uses the Electrical Resistivity Tomography (ERT) and groundwater resistivity measurements (WRM) in the field. A geoelectrical study was carried out in a sandy-loam site and the results were compared to those determined by particle size analysis using the Bouyoucos technique for textural analysis. The SRM technique was more accurate but slower than the ERT&WRM technique. The obtained results suggest a new application of geoelectrical methods for precisión farming, both for analysis of soil samples in the laboratory using SRM technique and to evaluate large tracts of agricultural land using ERT&WRM technique.