Study on the Spatial Distribution Patterns and Influencing Factors of Soil Organic Carbon Components in Ecological Vegetative Slope Areas

Understanding the spatial distribution patterns of soil organic carbon components in Ecological Vegetative Slopes (EVS) is crucial for optimizing restoration strategies, enhancing soil carbon sequestration capacity, and scientifically evaluating rehabilitation effectiveness. It is an important pathway for promoting sustainable development. This study investigated the effects of slope gradient, slope position, vegetation type, and cement content on the spatial distribution characteristics of soil total organic carbon (TOC) and its components (readily oxidizable organic carbon (ROC) and dissolved organic carbon (DOC)) through slope model experiments and laboratory analyses. The key findings revealed that (1) TOC, ROC, and DOC concentrations decreased with increasing slope gradient and upper slope positions, with steeper slopes amplifying positional effects and exhibiting surface-layer accumulation characteristics. (2) The highest TOC, ROC, and DOC content was achieved in the mixed planting slope with Bermudagrass and Magnolia under a substrate thickness of 3 cm and 3% cement content. Lastly, (3) soil pH increased with the slope gradient and upper positions, showing systematic variations across vegetation types and cement contents. Comparative analysis demonstrated that optimizing vegetation composition and cement dosage effectively enhanced SOC accumulation, while slope gradient and position dominated the spatial heterogeneity of carbon distribution. These results provide theoretical and practical guidance for the precision management of slope ecological restoration. These findings provide robust data support for the ecological sustainability of engineering slope restoration and the enhancement of soil carbon storage.