小兴安岭4种原始红松林群落类型生长季土壤呼吸特征

Soil respiration characteristics of four primary Korean pine communities in growing season at Xiaoxing'an Mountain,China

为阐明小兴安岭地带性植被原始红松林土壤呼吸各组分的碳排放速率及其对土壤水热变化的响应规律,采用挖壕法和红外气体分析法测定土壤表面CO2通量(Rs),确定4种原始红松林群落类型生长季的土壤总呼吸(Rt)中土壤微生物呼吸(Rh),根系呼吸(Rr)和凋落物呼吸(Rl)的贡献量动态变化及其影响因子。结果表明:生长季内,4种原始红松林群落类型的Rt、Rh、Rr具有明显的季节性变化,7-9月份较高,6月份和10月份较低。Rh对Rt的贡献量最高,平均在58.8%;Rr对Rt的贡献量次之,平均为26.5%;Rl对Rt的贡献量相对较小,平均为12.5%。生长季土壤呼吸速率与5cm深土壤温度相关性极显著(P<0.01)。Rr和Rh的Q10值分别为2.88和2.23。表明根呼吸对土壤温度的敏感性高于微生物呼吸。生长季平均土壤呼吸速率的依次为:椴树红松林(6.38μmol·m-·2s-1)>云冷杉红松林(6.32μmol·m-·2s-1)>枫桦红松林(5.95μmol·m-·2s-1)>蒙古栎红松林(2.86μmol·m-·2s-1)。4种原始叶红松林群落类型间的Rh和Rr也存在一定差异。

In order to ascertain the carbon emission rate of total soil respiration（Rt）,including soil microbial respiration（Rh）,root respiration（Rr）,litterfall respiration（Rl） and their response influence on soil temperature and water content of four typical primary Korean pine forest communities at the Xiaoxing＇ an Mountain,trenching-plot and infrared gas exchange analyzer approaches were used to measure soil CO2during the growing season.The results indicated that Rt,Rh,Rr and Rl of four primary Korean pine forest communities changed obviously seasonally.Rt,Rh,Rr of four communities were higher in July and September,lower in June and October.On average,contribution of Rhto Rt was 58.8%,ranked first and the second was Rr（26.5%）,the third was Rl（12.5%）.There was significant correlation between Rt and soil temperature in 5cm depth in all plots during growing season（P 0.01）.Q10of Rr and Rh was 2.88 and 2.23,respectively showing that the root respiration was more sensitivity to soil temperature than that of microbial respiration.The average soil respiration rate in growing season of the four communities ranked：Tilia-Pinus koraiensis（6.38μmol·m^-2·s^-1） Picea sp.,Abies nephlolepis-Pinus koraiensis（6.32μmol·m^-2·s^-1） Betula costata-Pinus koraiensis（5.95μmol·m^-2·s^-1） Quercus mongolica-Pinus koraiensis（2.86μmol·m^-2·s^-1）.Rh and Rr differed among the four primary Korean pine communities.