GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 3.2 - POSTER GNGTS 2023 potential of geophysical techniques lies in their indirect “fast and light” nature, especially when they are deployed in time-lapse mode (Singha et al., 2015; Blanchy et al., 2020b). In this work, we evaluated the ability of Electrical Resistivity Tomography (ERT) and Electro Magnetic Induction (EMI) methods for monitoring the effects of conventional (CONV) and conservation (CONS) agriculture. The aim is to highlight differences in soil water distribution caused by both short- and long-term effects of the two different practices. The monitoring activity was conducted in the Veneto Region (North Eastern Italy) at an experimental farm located in the low-lying Venetian plain (Fig. 1). Figure 1. The Sasse-Rami experimental farm location and zoom to the CONV and CONS fields. Experimental treatments were established in 2010 to compare CONV versus CONS management systems. Surveys occurred between December 2017 and April 2018 coupling soil characteristics measurements and geophysical surveys. Throughout our experiment, CONV field remained bare while CONS was covered by cover crops. For each field, three monitoring stations were equipped with multi-sensor probes, operating with a frequency domain reflectometry technique, which continuously monitored soil temperature (T, °C) and volumetric water content (VWC, %) at three depths (10, 30, and 55 cm). Five time-lapse geophysical surveys –i.e., ERT and EMI – were conducted on 15/12/2017, 05/02/2018, 14/03/2018, 26/03/2018, 26/04/2018. On the same date of the last survey, soil cores were collected with a hydraulic sampler down to 90cm at the same location as the monitoring stations (six in total) and then cut in 0-25, 25-50 and 50-90 cm layers in order to estimate bulk density (BD) and particle size distribution. ERT transects were collected using a Syscal Junior 72 resistivimeter (Iris Instruments, Orleans, France) with a Wenner array on a transect line of 14.1 m composed of 48 stainless-steel electrodes spaced 0.3 m. Processed as time-lapse survey (LaBrecque and Yang, 2012; Blanchy et al., 2020a), we obtained changes in EC (difference %) during time by subtracting the first