Influence of grazing patterns on the stability of soil aggregates in semi-arid grasslands

Global grassland degradation necessitates the identification of sustainable grazing management strategies. In semi-arid regions, grazing exclusion (GE), cold-season grazing (CG), and free grazing (FG) represent common practices in grassland ecosystems, yet the long-term ecological consequences of these patterns on plant community structure and soil aggregate stability remain inadequately elucidated. In this study, we evaluated the effects of GE, CG, and FG on soil organic carbon, soil water content, soil bulk density, soil aggregates, and vegetation indicators in Xilamuren steppe, a semi-arid grassland in northern China through field sampling and laboratory analyses in 2024. Our findings revealed that, compared to CG and FG, GE significantly enhanced aboveground and belowground biomass, species diversity, and soil physical-chemical properties in the 0–30 cm layer. The dominant plant species in GE and CG sites were Stipa krylovii , Leymus chinensis , and Agropyron cristatum , whereas Stipa krylovii , Artemisia frigida , and Leymus chinensis were predominant in FG site. Different grazing patterns led to distinct soil aggregate distributions, with >2.00 and <0.25 mm aggregates exhibiting the highest content in different soil layers depending on the grazing patterns. All grazing management strategies significantly improved soil aggregate stability, with the overall stability following the order: GE>CG>FG. Furthermore, random forest modeling identified plant species diversity, plant growth traits, and grazing patterns as the primary determinants of soil aggregate stability. Collectively, these results offer valuable insights into the sustainable management and ecological restoration of semi-arid grasslands under different grazing pressures.