Characterizing root system characteristics with Electrical Resistivity Tomography: a virtual rhizotron simulation

Electrical Resistivity Tomography (ERT) has become an indispensable tool to monitor soil water content in cropped field. Yet the impact of roots on the ERT measurements is often neglected and not completely understood. Our measurements on root segments suggest that roots are more electrically conductive than soil for typical soil parameters and thus should have a measurable impact on ERT signals. In this work, we have developed a virtual rhizotron model with root water uptake and root growth. ERT simulations are then carried out for the conductivity map generated for various root architectures and soil conditions in the virtual rhizotron to study the impact of roots on ERT forward (current and voltage patterns) and inverse solutions. With these virtual experiments, we investigate which factors help discriminate the impact of roots from soil with ERT inversion.