Two-Dimensional Electrical Resistivity Investigation of Plants Roots and its Implication in University of Benin Engineering Field, Ugbowo, Edo State, Nigeria

Abstract

The geophysical study of the spread of plant roots have become imperative due to its effect on buildings. Most buildings constructed close to trees; without taking into consideration the extent of root spread, have experienced cracks which sometimes lead to the collapse of such buildings. To investigate the horizontal and vertical spread of plant roots at the University of Benin Engineering field, Edo State, Nigeria, a two-dimensional electrical resistivity imaging was done using the Wenner-Schlumberger array configuration. Data were collected along two profiles; profile 1 was taken along tree paths and profile 2 along grassland area, some distance from profile 1. Profile 1 showed a very resistive top layer underlain by a low resistive layer. The top layer which appeared to be highly resistive was due to the presence of fluid absorbers within that layer. The fluid absorbers are the roots from the trees which are distributed both vertically and horizontally within the layer. With the inversion results, the depths of the roots were estimated to be between 5.00m and 7.50m from the surface; with resistivity values of between 610.00Ωm to 1700 Ωm. The resistivity distribution obtained in profile 2 appears to be more homogeneous than the results obtained from profile 1 with resistivity values of between 320 Ωm to 3500.00 Ωm from the top layer to the bottom layer. The uniformity in the resistivity distribution with depth was due to the absence of tree roots within the formation

Keywords: Tree roots, inhomogeneous, resistivity