Transforming electrical resistivity tomographies into volumetric water content ones: a strategy for optimizing irrigation in horticulture.

Agricultural water management is becoming an increasingly actual issue in a period of severe climate changings. Sustainable water management requires adequate knowledge of soil water availability and its storage capacity. The correct management of irrigation water requires a good knowledge of the volumetric water content (VWC) in the soil. VWC is a parameter that can be measured using soil humidity sensors, and it can help understanding how the irrigation water distributes in the soil. However, these sensors are point humidity monitoring systems, that means they provide information limited to the vertical where they are installed and do not allow a 2D or 3D reconstruction of the water content in the subsoil. As well known, Electrical Resistivity Tomographies (ERT), a non-invasive geophysical method, estimates the spatial and temporal variations of soil resistivity (and thus of its inverse, i.e., conductivity), which is linked to parameters such as water content. Unlike point-based soil moisture sensors, ERT provides a broader view of water distribution in the soil. Thus, the goal of this study was to use electrical conductivity (EC) by full 3D-ERTs and moisture sensors to estimate the volumetric water content in the soil.