Objective The aims were to reveal the accumulation and component distribution of soil organic carbon (SOC) in the coal mining area of northern Shaanxi, in order to clarify the characteristics of the source of SOC and to explore its response mechanism to different vegetation.

Methods The study was conducted on aeolian sandy soils under three typical vegetation types—grassland, shrubland and grass-shrubland—at the Hongliulin coal mining area in northern Shaanxi. The SOC content, organic carbon fractions, and carbon sources were examined across six soil layers, with the sources analyzed in the top three layers.

Results Vegetation type significantly influenced SOC accumulation and distribution patterns. The SOC contents under shrubland increased significantly by 13.77% - 68.19% and 30.03% - 112.47% compared to grassland and grass-shrubland soils. The SOC fractions also showed marked increases, with the active and inert SOC fractions under shrub vegetation exhibiting the highest contents and proportions, resulting in a more stable carbon pool. The SOC source composition varied across vegetation types, and the total lignin in shrub soils increased by 60.79% - 137.26% and 58.35% - 109.71%, total amino sugars increased by 55.41% - 136.59% and 68.97% - 163.10% relative to grassland and grass-shrubland soils, respectively. Shrub vegetation promoted greater accumulation of amino sugars and lignin in the soil. Microbial-derived organic carbon was identified as the primary SOC source in the aeolian sandy soils, with a relatively higher proportion of fungal-derived carbon.

Conclusion Shrub vegetation has a higher content of organic carbon and carbon fractions, and its sources of organic carbon (amino sugars and lignin) are higher abundance and more stable than grasses and grass - shrubs. Shrubs enhance the accumulation of SOC pools and improve their chemical recalcitrance, and are the preferred vegetation type for increasing soil carbon sequestration in the aeolian sandy soil area of the Red Willow Forest Coal Mine.