Form ER (Electrical Resistivity) to VWC (Volumetric Water Content) tomographies: an agrogeophysical application

This study presents an agrogeophysical application that combines Electrical Resistivity Tomography (ERT) with conventional soil moisture sensors to enhance the estimation of Volumetric Water Content (VWC) in agricultural soils. The ERT experimental setup included 72 electrodes arranged in three parallel rows, allowing full 3D data acquisition down to a depth of 1.20 m. Between June and August 2023, six ERT surveys were conducted under controlled conditions, and data were compared with those from Diviner2000 and ECH2O-10HS VWC sensors. Results showed a strong linear correlation between soil electrical conductivity (EC) and VWC at two different monitoring points. This relationship enabled the transformation of EC tomographies into VWC tomographies, resulting in continuous spatial maps of soil moisture. The findings confirm that ERT is a reliable tool for quantitatively assessing soil moisture, supporting more efficient and informed irrigation management in precision agriculture.