草毡寒冻雏形土CO2释放特征

研究了植物生长季节海北高寒草甸生态系统高寒嵩草草甸覆被下草毡寒冻雏形土的 CO2 释放速率。其结果表明 :CO2 释放速率有明显的日变化和季节动态。日最大排放速率多出现在 1 4 :0 0～ 1 6:0 0时 ,最小排放速率在 6:0 0～ 8:0 0时。植物生长季日最大振幅为 797.75mg/m2·h,最小振幅 1 97.33mg/m2·h。CO2 排放白天大于夜晚。不同物候期 CO2 释放速率不同 ,其顺序为草盛期 >枯黄期 >返青期。生长季土壤 CO2 释放速率的范围是 4 41 .72 mg/m2 · h± 1 55.2 9mg/m2· h,最大日均值为 681 .0 6mg/m2 · h( 7月 1 6日 ) ,最低值 1 76.65mg/m2 · h ( 6月 1日 )。退化草地土壤 CO2 释放速率明显低于未退化草地 ,生长季平均日均值低 1 37.4 7mg/m2·h。相关分析表明 :土壤 CO2 排放速率与气温、地表温度、土壤5cm、1 0 cm、1 5cm、2 0 cm、30 cm地温均呈显著和极显著相关关系。温度是影响土壤 CO2 释放速率的主要因子。

Carbon dioxide emission of Mat cryo-sod soil in the Haibei alpine meadow ecosystem

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 CO2 emission rate had significant diel fluctuation and seasonal dynamics.Maximum rate of CO2 emission appeared at 14:00～16:00 and minimum at 6:00～8:00. The maximum diel amplitude was 797.75 mg/m2*h (16 Aug.),the minimum amplitude was 197.33 mg/m2*h (1 June) and the CO2 emission rate of daytime was greater than that of night. Rate of CO2 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 CO2 emission rate were 441.72±155.29 mg/m2*h,681.06 mg/m2*h and 176.65 mg/m2*h，respectively. The rate of CO2 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/m2*h than Mat Cryo-sod soil. Correlation analysis showed that CO2 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 CO2 emission in Mat Cryo-sod soil.