Effects of Organic Matter Content on the Resistivity and Pore Structure of Waste Soil

With the accelerated development of global urbanization, the generation of organic solid waste has also increased. When mixed with soil, these organic wastes form waste soil, significantly altering the soil's structure and physical properties. When mixed with soil, such organic waste forms abandoned soils, significantly altering their structure and physical properties. Indoor experiments were conducted under different moisture contents (8%-24%) and organic-matter contents (0%-55%). In the R-X mode, the in-phase resistance was measured at 10 kHz, and nitrogen adsorption tests were used to characterize the pore structure and perform fractal fitting. The results show a significant negative correlation between water content and resistivity. At an organic matter content of 50% and a water content of 24%, the number of conductive pathways markedly increased, reducing resistivity to 30.71% of its peak value. Resistivity exhibited an “increase-then-decrease” trend with rising organic matter content, reaching a maximum of 435.19 Ω·m at 50% organic matter, which is 1.3 times higher than at 40%. Under low water content (below the plastic limit of 19.1%), resistivity varies markedly; in contrast, under high water content (above the plastic limit), its variation is relatively small. Focusing on the electrical response under a high-frequency condition , this study provides a clearer mechanistic interpretation of resistivity variations in wasted soils. The findings may offer useful reference for monitoring and comparative assessments in soil ecosystem management and vegetation restoration projects.