高寒草甸不同草地微斑块土壤团聚体分布及其与有机碳矿化的关系OA

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.