NS36A-05 - Understanding the Soil Electrical Signatures in a Restored Wetland Using Spectral Induced Polarization and Electromagnetic Induction
Presentation Information
TitleNS36A-05 - Understanding the Soil Electrical Signatures in a Restored Wetland Using Spectral Induced Polarization and Electromagnetic Induction
Session Start2022-12-14 16:45:00 CST
Session End2022-12-14 18:15:00 CST
LocationMcCormick Place, S105a
AuthorEfemena Destiny
Presentation TypeOral
AbstractThe use of geoelectrical methods for investigating variations in wetlands soil properties could dramatically expand our understanding of wetlands� hydrological and biogeochemical functions. However, existing petrophysical relationship may be limited in wetland soils due to their hydric nature. Hence, this study focuses on advancing our mechanistic understanding of wetland soils� electrical response in other to adapt existing petrophysical models for predicting wetlands soil properties including moisture, and organic matter from measured electrical signals. In this study, we use an EM-38-MK2 operated at a 14.5 kHz frequency to obtain the spatial distribution of soil electrical conductivity and identify soil boundaries. Core samples were collected at 0-30 cm depth at each soil boundary using an AMS soil bulk density sampler. We performed spectral induced polarization (SIP) measurement on 18 soil cores in the laboratory using a frequency range of 0.01 Hz to 10 kHz. All samples were partially saturated using 78 ?S/cm of brine (NaCl) solution prior to the SIP measurements. We recorded the impedance (z) and phase shift (?) response using four electrodes and computed the real and imaginary complex conductivity. Using the same setup for the SIP, we estimated the formation factor (F) for each sample and obtained F values between 4.35 and 11.67 through repeated measurement of the bulk and fluid resistivity at different salinity concentration. We also measured the physical-chemical properties of the soil including the soil texture, moisture content, organic matter, bulk density, and porosity. Our result shows a strong correlation (71% & 85%) with ?' and measured soil properties, but no correlation with ?'' at 1.14 Hz. We then evaluate ? variations with measure soil properties where we observe a strong correlation (63% & 65%). This study indicated that wetland soil electrical response has the strongest effects on ?' and ? variations which is foremost arising from the variation in moisture content. And other apparent strong relations such as SOM and soil textures (clay content) were due to a high correlation with moisture content.