Probabilistic inversion of EM38 data for 3D soil mapping in central Iran

Accurate determination of near surface soil electrical properties is important for agricultural and environmental management. In this respect, low frequency electromagnetic induction (EMI) has been widely used to measure soil apparent electrical conductivity. However, the potential to model soil subsurface layering has not been fully realized using EMI data. In this paper, we applied a probabilistic optimization approach, namely DREAM (ZS), on Geonics EM38 data to explore the robustness of this approach for soil subsurface conductivity mapping. The EM38 data was measured from the Ardakan region in the province of Yazd located in central Iran. Several soil samples were taken and were further analyzed in a laboratory to derive soil textural and physical parameters. The probabilistic inversion was performed in a joint multi-configuration framework considering a five layered model. The estimated values are mainly in agreement with the clay map (as the most influential factor); nevertheless, soil salinity data and inversely estimated conductivity values are poorly correlated for deeper layers due to the aridic condition and high clay content in the study area. DREAM (ZS) optimization approach appears to be promising for accurate retrieval of soil conductivity depth profile from EM38 data.