Loess Soil Structural Changes Induced by Bio- and Synthetic Polymer Stabilizers: Geoelectrical Insights

Abstract. Traditional assessments of soil aggregate stability rely on destructive, ex situ protocols that fail to capture the continuous evolution of soil architecture. This study evaluates the divergent stabilization trajectories induced by chia seed mucilage (CSM) and anionic polyacrylamide (A-PAM) in loess soil over a 20-day incubation. By integrating Spectral Induced Polarization (SIP) with microbial respiration and tracer breakthrough experiments, we track the transition from initial aggregation to long-term structural outcomes. Results demonstrate that CSM-induced stabilization is strictly transient; rapid microbial degradation of the biopolymer results in progressive reversal of the induced structural modifications and a reversion to baseline hydraulic behaviour. In contrast, A-PAM provides persistent physicochemical reinforcement, establishing a dual-porosity regime characterized by immobile water domains and preferential flow pathways. SIP signatures effectively resolved these dynamics: high-frequency shifts in quadrature conductivity (σ'' ) provided geoelectrical evidence of micro-aggregate formation, while the development of a 'conductive reservoir' in in-phase conductivity (σ' ) identified hydraulically isolated ion accumulation. These findings establish SIP as a high-resolution, non-invasive proxy for monitoring the interplay between biochemical persistence and the mechanical stabilization of soil structure.