A comparative study using 3D measurement with ERT method and Ohm mapper instrument to assess soil water content and root system in a vineyard: a Case study in Montalcino, Siena, Italy

Soil water availability deeply affects plant physiology. In viticulture it is considered a major contributor to the “terroir” effect. The assessment of soil water in field conditions is a difficult task, especially over large surfaces. New techniques are therefore required in order to better explore variations of soil water content in space and time with low disturbance and with great precision. This study focuses on a comparison between two geophysical surveys within an agronomic framework, involving the inversion of 3D ERT data from the galvanic contact resistivity (GCR) method and 3D data using ohm mapper from the capacitively-coupled resistivity (CCR). By minimizing misfit in model parameters, the inversion process enhances data-fitting in terms of resolution and accuracy of subsurface models within the inversion theory framework. Datasets were acquired in a red Sangiovese grape vineyard ("Tenuta il Poggione '' - Montalcino, Siena, Italy), covering a 225 m2 area (15m×15m). Employing a 3D ERT configuration for maximum resolution perpendicular to the vineyard rows and 2D CCR sections along the rows, the study encompasses the vineyard’s root system. We compare the results from individual 3D ERT and CCR inversions, with the primary objective of assessing soil water content and root system more accurately. This study demonstrates the enhanced effectiveness and precision of both methods when applied to geoelectrical data in agro geophysical investigations.