Electrical Resistivity Tomography (ERT) to assess the drip irrigation water in a field cultivated with melon

Characterization of agricultural soils using geophysical techniques makes it possible to study the heterogeneity of a soil and the preferential pathways of water flows without causing disturbances to soil and plants. Increased knowledge of soil heterogeneity allows the most optimal management of the water resource in terms of crop, yield and sustainability. In this study, time lapse monitoring, using electrical resistivity tomography (ERT), is proposed as a reliable and noninvasive technique to quantify the movement of water flows during the irrigation process. ERT surveys were conducted in melon cultivated land in southern Tuscany (Italy). Four survey campaigns were carried out between June and August 2022, in which ERT data were collected by taking measurements, before, during, and after the irrigation phase. The investigation was conducted with a 3-D grid in which the 72 electrodes were spaced 0.3 m apart and arranged in three parallel lines, 0.3 m apart and 6.9 m long, for a total of 24 electrodes in each line. The plants were located above a ridge having a height of 20 cm with respect to the ground level and the electrodes were positioned to incorporate 5 melon plants in the configuration. A dipole-dipole configuration was adopted for the acquisition of electrical resistivity data. Commercial ViewLab 3D software was used to process the geoelectrical data.