Abstract:Grasslands,as the central components of terrestrial ecosystems,is directly participate in the global carbon cycle. The study of grassland carbon storage has always been a hot and difficult point in the forefront of ecological science. Alpine meadows,which cover much of the Qinghai-Tibet Plateau,the 'Third Pole of the Earth’,are vital for carbon sequestration and water conservation. The effects of various conservation and utilization strategies on the carbon storage in alpine meadows are not yet fully comprehended. Examining the vegetation-soil carbon density across various conservation and utilization practices in alpine meadows is crucial for precisely evaluating carbon reserves and ecological conservation efforts. This study examined the impacts of six distinct management practices on alpine meadows: year-round grazing,summer grazing,winter grazing,grazing exclusion,reseeding grassland,and artificial grassland establishment. To assess these impacts,aboveground biomass,litter,and soil samples were systematically collected from three soil depths (0-10 cm,10-20 cm,and 20-30 cm). To improve the accuracy of carbon density estimation under various conservation and utilization practices,this research compares vegetation and soil carbon densities,their root-to-shoot ratio,and their spatial distribution. The goal is to provide a solid theoretical foundation for the scientific management of alpine meadow ecosystems. The results showed that: (1) carbon density demonstrated significant differences within the vegetation-soil system of alpine meadows in under various protection and utilization regimes,with artificial grasslands>enclosure>reseeding,and winter grazing>summer grazing>year-round grazing in terms of carbon density content; (2) among the three conservation measures,reseeded grasslands exhibited a notably higher vegetation carbon density (619.08g/m2) compared to artificial and enclosed grasslands (P<0.05). Artificial grasslands boasted significantly higher soil carbon density (19409.25g/m2),vegetation-soil system carbon density (19654.90g/m2),and a soil carbon density/vegetation-soil system carbon density ratio of 99%,in contrast to reseeding and enclosed grasslands (P<0.05),while the root-to-shoot carbon density ratio (2.71 ∶ 1) was lower than other measures; (3) among the three utilization measures,winter-grazed alpine meadows had significantly higher vegetation carbon density (1305.63g/m2),soil carbon density (14369.58g/m2),vegetation-soil carbon density (15740.66g/m2),and root-to-shoot carbon density ratio (27.14 ∶ 1) compared to summer-grazed and year-round grazed grasslands,with a lower soil carbon density/vegetation-soil system carbon density ratio of 91%. In conclusion,the implementation of artificial grassland and winter grazing practices represents an optimal management approach for augmenting the carbon sink potential of alpine meadow ecosystems. These findings underscore the importance of tailored conservation strategies for enhancing carbon sequestration and provide data support for maximizing the carbon sequestration potential of alpine meadow ecosystems under various conservation and utilization practices.