The rate of Carbon dioxide emission was determined in the
Mat cryo-sod soil covered with alpine Kobresia humilis meadow in
the region of Haibei Alpine Meadow Ecosystem Research Station, using a CI-301PS photosynthetic instrument during the plant growing period (May～Sept.). The results indicated that: The CO 2 emission rate had significant diel fluctuation and seasonal dynamics.Maximum
rate of CO 2 emission appeared at 14:00～16:00 and minimum at 6:00～8:00. The maximum diel amplitude was 797.75 mg/m 2·h (16 Aug.),the minimum amplitude was 197.33 mg/m 2·h (1 June) and the CO 2 emission rate of daytime was greater than that of night. Rate of CO 2 emission was different with changing of the phonological periods, and the pattern was observed in order of Exuberance>Withering>Green up. During the plant growing period ,range,maximum and minimums value of diel CO 2 emission rate were 441.72±155.29 mg/m 2·h,681.06 mg/m 2·h and 176.65 mg/m 2·h,respectively. The rate of CO 2 emission in the degraded
Mat Cryo-sod soil was lower than Mat Cryo-sod soil and the diel average value was less 137.47 mg/m 2·h than Mat Cryo-sod soil. Correlation analysis showed that CO 2 emission rate significantly correlated with air temperature, soil surface temperature and 5cm 10cm 15cm 20cm 30cm soil temperature. The temperature is a one of dominant factor, and it effects the rate of CO 2 emission in Mat Cryo-sod soil.