关键词: 多年冻土, 甲烷通量, 土壤理化性质, 青藏高原

Abstract: Global warming stimulates soil organic carbon decomposition in permafrost regions, which releases methane (CH₄) into the atmosphere. However, the relationship between CH₄emission flux and environmental factors in permafrost regions is unclear. In this study, we measured the CH₄ release rate of alpine wet meadow, alpine meadow, and alpine grassland in the permafrost region in the northern Qinghai-Tibet Plateau from June 2019 to January 2020, using static chamber-gas chromatography. We examined the relationships of CH₄ emission and soil physical and chemical properties. The results showed that the average monthly CH₄ release rate was0.080 mg·m^-2·h^-1 in alpine wet meadow, -1.132 mg·m^-2·h^-1 in alpine meadow, and -0.541 mg·m^-2·h^-1 in alpine grassland. The CH₄ emission flux showed obvious seasonal variations. The CH₄ emission fluxes in July and August were significantly higher than that in other months. There was a positive correlation between soil temperature and CH₄ emission flux. The rate of CH₄ production was positively correlated with soil moisture and total carbon content in the 0-15 cm layer of alpine wet meadow, and positively correlated with the contents of soil organic carbon, total carbon, and total nitrogen in the 15-30 cm layer. The rate of CH₄ production was negatively correlated with soil conductivity in the 15-30 cm layer of the alpine steppe. Our results indicate that meadows and grasslands are CH₄ sinks, and that vegetation types are the main factors affecting CH₄ release in permafrost regions. The CH₄ release rate is related to soil carbon and nitrogen contents, electrical conductivity, and soil temperature.

Key words: permafrost, methane flux, soil physical and chemical properties, Qinghai-Tibet Plateau.