松嫩平原旱生芦苇群落土壤呼吸动态及影响因子

Dynamics of soil respiration under Phragmites australis community in dry habitats of Songnen Plain and related affecting factors

为研究松嫩平原旱生芦苇群落土壤呼吸作用的动态变化及其影响因子,于2011年5—10月采用LI-6400土壤呼吸监测系统对旱生芦苇群落土壤呼吸进行连续野外观测,并分析水热因子对土壤呼吸的影响。结果表明:芦苇群落土壤呼吸具有明显的日变化和季节变化特征;其日变化为明显的单峰曲线,土壤呼吸速率峰值出现在中午11:00—13:00;7和8月芦苇群落土壤呼吸作用最强,10月土壤呼吸作用最弱。影响旱生芦苇群落土壤呼吸的主导因子是温度,土壤呼吸与近地表空气温度以及土壤0～10、10～20、20～30cm温度均有显著相关性(P<0.01),而近地表空气温度和土壤表层温度对土壤呼吸的影响最大。在5—10月芦苇群落土壤呼吸温度敏感性Q10值为1.2～1.65,变异系数为15.4%。土壤含水量和近地表空气相对湿度不是影响该地区芦苇群落土壤呼吸的主要因素。

Soil respiration is one of the important components in global carbon cycle, and a sensitive indicator of many soil processes that control soil metabolism. In order to understand the dynamics of soil respiration under the Phragmites australis community in dry habitats of Songnen Plain, Northeast China, a field observation on the soil respiration was conducted from May to October 2011 by using LI-6400 automated soil CO2 flux system. There existed obvious diurnal and seasonal patterns of the soil respiration. The diurnal curve of the soil respiration was unimodal, with the peak appeared at 11：00-13：00, and the seasonal change of the soil respiration was with the maximum （4.8 μmol·m^-2·s^-1） in July and August and the minimum （1.51 μmol·m^-2·s^-1） in October. The main factor affecting the soil respiration was temperature. The soil respiration rate was significantly correlated with the nearground ambient air temperature and the soil temperature at depths 0-10, 10-20, and 20-30 cm, of which, nearground ambient air temperature and the soil temperature at depth 0-10 cm were the two most important controlling factors. The Q10 values of the soil respiration from May to October varied from 1.2 to 1.65, with a mean value of 1.39 and a coefficient of variation of 15.4%. Soil moisture content and near-ground air humidity were not the main environmental factors affecting the soil respiration.