Soil quality dynamics across a landslide profile from intact slopes to displaced material and bedrock

Abstract. Landslides modify soil systems by disrupting pedogenic processes, altering physical structure, and redistributing chemical constituents. To assess these effects and address key knowledge gaps, this study examines soil quality dynamics along a geomorphological transect crossing intact slopes, displaced landslide material, and parent substrate in the Transylvanian Basin. A suite of physico-chemical, together with magnetic parameters, considered herein as a previously underutilized yet promising proxy for soil degradation, was analysed to identify the soil properties most affected by landsliding, test for statistically significant contrasts between disturbed and undisturbed soils, and determine the most reliable indicators of soil degradation. Magnetic properties showed the clearest diagnostic response: mass-specific and frequency-dependent susceptibility were markedly reduced within the landslide, reflecting the removal or mixing of magnetically enriched horizons. Landslide-affected soils exhibited higher bulk density, lower organic matter, elevated electrical conductivity, and homogenized clay patterns compared with intact profiles. These results demonstrate that landslides profoundly alter soil composition and structure, and highlight magnetic susceptibility, organic matter, and electrical conductivity as robust indicators for assessing disturbance severity. The findings provide a comprehensive framework for evaluating soil degradation in landslide-prone environments.