To investigate whether seasonal freeze-thaw promotes the emission of nitrous oxide （N₂O） and accelerates the gaseous loss of nitrogen in the talus plateau vegetation ecosystem， this study focused on the grassland （Thylacospermum caespitosum） pad vegetation at an altitude of 4000-4400 m on the Gangshigacha snow peak in the eastern part of the Qilian Mountains. The soil （0-30 cm） temperature， humidity， nutrient dynamic characteristics， and N₂O flux were monitored continuously for two years. The results showed that the soil experienced approximately 70 daily freeze-thaw cycles throughout the year， divided into four periods： unstable thawing period （25 times）， stable thawing period， unstable freezing period （45 times）， and stable freezing period. For every 100-meter increase in altitude， the average start and end time of soil freeze-thaw was delayed or advanced by 3.88 days. The N₂O emission was the most significant during the unstable thawing period （accounting for only 5.5%-6.8% of the entire year）， with a cumulative emission （225.97 g·hm^-2） accounting for 35.88% of the annual total， a maximum emission rate of 24.52 μg·m^-2·h^-1， an average flux of 13.63 μg·m^-2·h^-1， which was 1.39 times the annual average， and the cumulative emission during the non-growing seasons （excluding the stable thawing period） accounted for as high as 74.09%. The emission was dominated by soil water and heat， pH， and substrate scarcity， leading to low production. Under climate warming， the freeze-thaw driven nitrogen gas loss of N₂O in the ice margin zone intensified， and further research on the water and heat conditions and nitrogen transformation mechanism is needed.

Climate change  /  Alpine periglacial zone  /  Cushion vegetation  /  Freeze-thaw action  /  Nitrous oxide