GNGTS 2013 - Atti del 32° Convegno Nazionale

We present on the results of experiments of 3D and 2D Micro-ERT, supported by Time Domain Reflectometer (TDR) measurements and tensiometers measurements in a very well monitored fruit garden of Val di Non, Trentino Region and for the Venice lagoon salt marsh environment (Italy). In the specific we performed 3 controlled irrigation tests for the apple tree and 1 field experiment in the Venice lagoon during marsh flooding. Very different seasonal and environmental conditions are highlighted with interesting behaviors. In order to quantify soil moisture content in the first case study, we performed laboratory analysis on earth samples to evaluate the electrical response at different saturation steps and to calibrate petro-physical relationships. This allows transforming geophysical quantities into hydrological quantities, which represents a key point to clearly understand the groundwater dynamics and soil-plant interactions. Test sites. Test site 1 is located in Cles (650 m amsl), in the Val di Non valley of Trentino Region, North Italy. We installed our micro ERT 72 channels (48 buried electrodes + 24 surface electrodes) and 2 TDR antennas around a single tree in an apple culture, already monitored in the framework of the FP7 CLIMB project, with controlled irrigation system and monitored weather-stations. The site is located on a moraine versant of an ancient Wurmian glacier valley and presents an heterogeneous glacial deposit (presence of blocks and pebbles in a sandy-silty matrix). We conducted monitoring of both long term natural changes and controlled irrigation experiments around a single apple tree, in order to assess value, strengths and limitations of the non invasive techniques for root/vadose zone monitoring. Test site 2 is located in the northern part of the Venice Lagoon (Italy), in a periodically flooded salt marsh. In this case the ERT apparatus had 24 buried electrodes plus 24 surface Fig. 1 – a) August 2011 experiment: resistivity ratio with respect to background at four time steps. In (a), A and B indicate the locations of the two drippers. b) May 2012 experiment: resistivity ratio with respect to background at four time steps. Surface at 30 cm depth. c) November 2012 experiment: resistivity ratio with respect to background at four time steps, (from Boaga et al. , 2013, modified). a) b) c) 92 GNGTS 2013 S essione 3.2