Agricultural soil characterization using 2D electrical resistivity tomography (ERT) after direct and intermittent digestate application

Abstract

This work aims to investigate the applicability of electrical resistivity tomography (ERT) as a non-destructive tool of agricultural soil characterization after digestate of fruit and vegetable (DFV) amendment application. DFV was applied at 30 t ha−1 in one application (D1), split into 2 (D2) and 6 applications (D6), and compared with initial state (IS) on field plots of 10 m2. The high-resolution 2D ERT prospecting was performed using a ABEM SAS4000 multi-electrode Lund imaging survey system with a set of 16 electrodes evenly spaced 0.1 m. The resistivity values with ERT profiles using the Wenner array range globally from 0 to 200 Ω m. All treatments proposed decreased soil resistivity to 0–30 cm depth profile. Splitting digestate shows more intensive decreasing resistivity in the top layer and less in the bottom, and moves the iso-resistivity lines lower than 30 Ω m from 7 cm depth to 12, 20, and 30 cm depth, respectively, for D6, D2, and D1. The resistivity folding at 15 to 30 cm depth was 87, 80, and 67% then 58, 42, and 37%, respectively, for D1, D2, and D6. The low resistivity values may be due to soil organic matter flow illustrated. Digestate applied once acted on the soil with heterogeneous way along the profile. Splitting it increases the thickness of foam layer homogeneously. ERT seems a promising technique for the survey of soil organic matter content monitoring, dispersion, and assessment.