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Acta Prataculturae Sinica ›› 2026, Vol. 35 ›› Issue (2): 15-27.DOI: 10.11686/cyxb2025079

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Distribution of soil aggregates in different vegetation micro-patches in alpine meadows and the relationship with organic carbon mineralization

Jing WANG1,2(), Xu-dong LI1, Tian-hu HAN1,4, De-cao NIU1, Chun-li BAI3, Ding GUO1()   

  1. 1.State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems,Lanzhou University Alashan Desert-Oasis Grassland Field of Scientific Observing Stations,Lanzhou University,College of Pastoral Agriculture Science and Technology,Lanzhou 730020,China
    2.Inner Mongolia University,School of Ecology and Environment,Hohhot 010030,China
    3.Inner Mongolia Academy of Agricultural & Animal Husbandry Sciences,Grassland Research Institute,Hohhot 010031,China
    4.Gansu Desert Control Research Institute,Lanzhou 730030,China
  • Received:2025-03-11 Revised:2025-05-06 Online:2026-02-20 Published:2025-12-24
  • Contact: Ding GUO

Abstract:

Micro-vegetation patchification is a critical process during the retrogressive succession of grasslands. This study explored how vegetation patches influence soil aggregate distribution and stability, and the subsequent effects on soil organic carbon (SOC) mineralization in the Qinghai-Tibet Plateau. Soil aggregates were fractionated using the wet-sieving method into three size classes: macro-aggregates (>250 μm), micro-aggregates (53-250 μm), and silt-clay fractions (<53 μm). SOC mineralization was quantified through indoor incubation experiments. It was found that macro-aggregates dominated all vegetation patches (55.31%-74.01%), but their content and aggregate stability significantly decreased in non-native patches compared to the native vegetation (CK). Notably, macro-aggregate loss was as high as 25.27% in bare areas (BA) (P<0.05). SOC content in macro-, micro-, and silt-clay fractions was highest in CK, Potentilla fruticosa, and Polygonum viviparum patches, followed by Ligularia virgaurea (LV) and BA. SOC cumulative mineralization quantity peaked in LV patches (12.38 g·kg?1) and was lowest in BA (8.26 g·kg?1). Additionally, cumulative mineralization rate was significantly higher in LV and BA than in other patches (P<0.05). Positive correlations were observed between SOC cumulative mineralization quantity and macro-aggregate content as well as aggregate stability (P<0.05). Conversely, cumulative mineralization rate was negatively correlated with aggregate stability and C/N ratio (P<0.01). These findings suggest that analyzing aggregate composition, stability, and mineralization dynamics during patchification processes can provide scientific insights for sustainable grassland management and accurate climate change assessments in the Qinghai-Tibet Plateau.

Key words: Qinghai-Tibet Plateau, soil particle size distribution, soil organic carbon (SOC), mineralization rate