[CO2 flux characteristics from degenerated mat cryo-sod soil during plant growing period]

The carbon dioxide (CO2) emission rate was studied in the degenerated mat cryo-sod soil covered with alpine Kobresia humilis meadow at the Haibei alpine meadow ecosystem research station, with CID-301 ps CO2 analytical instrument during plant growth period (May-Sep, in 1998). The results showed that the CO2 emission rate had obvious daily variation and seasonal dynamics. The maximum rate of CO2 emission appeared at 12:00-14:00, and the minimum rate appeared at 6:00-8:00. The max daily amplitude was 462.49 mg.m-2.h-1, while the minimum daily amplitude was 114.97 mg.m-2.h-1. The CO2 emission rate varied with phonological periods, and the order was exuberance > withering > green up. The maximum daily average value was 480.76 mg.m-2.h-1 (Aug.18th), and the minimum daily average value was 140.77 mg.m-2.h-1 (May.9th). Correlation analysis showed that there was a significant relationship between CO2 emission rate and air temperature, soil surface temperature and soil temperature in 5 cm, 10 cm, 15 cm, 20 cm, and 30 cm. Temperature was the dominant factor that affected the CO2 emission rate in degenerated mat cryo-sod soil.