DEPTH-SPECIFIC GEOPHYSICAL MODELLING FOR UNDERSTANDING GEOCHEMICAL DYNAMICS IN SOILS

Quantifying hydrogeochemical properties and behaviors within a soil is key to understanding and describing soil-water-environment interactions. Properties that dictate this relationship can vary as a function of space in the vertical and horizontal direction and time. Of utmost importance is the shallow subsurface attributes that drive local recharge rates and control runoff and infiltration potential in a watershed. This introduces the need to model this heterogeneity and resolve stratification in near-surface sediments. This study focuses on the utilization of electrical conductivity (EC_a)-soil property relationships to non-invasively model and map spatio-temporal variability with a focus on fine depth intervals.

Collaborative research between Texas Christian University and two Algerian institutes aims to develop predictive models for discrete interval mapping of water content, salinity, and clay content. This will be generated using a Geonics Limited EM38-MK2 probe held at different heights above the ground to alter the penetration depth. The primary focus is on assessing the transferability of EC_a-soil property models across time and space and exploring the refinement of current 3D approaches towards a more generalized EC_a model.

This research will result in higher resolution predictive models that will enhance the ability to map vertical and horizontal heterogeneity noninvasively. The ease of EC_a data collection combined with the potential to discretize a profile into fine scale intervals make this method ideal for characterizing variability in near surface geophysical and geochemical properties for shallow sediments. Improvements to mapping these geospatial characteristics will enhance the ability to track landscape evolution and watershed-soil interactions.