温度和水分对羊草草原土壤呼吸温度敏感性的影响  

Effect of temperature and moisture on temperature sensitivity of soil respiration of Leymus chinensis steppe

作　　者：罗光强[1,2] 耿元波[1] 

机构地区：[1]中国科学院地理科学与资源研究所,北京100101 [2]中国科学院研究生院,北京100049

出　　处：《生态环境学报》2009年第5期1938-1943,共6页Ecology and Environmental Sciences

基　　金：中国科学院地理科学与资源研究所自主部署创新项目(200905009);国家"十一五"支撑计划(2006BAJ10B04)

摘　　要：采用静态暗箱-气相色谱法对内蒙古锡林河流域羊草(Leymus chinensis)草原土壤呼吸进行测定,研究了温度和水分条件对土壤呼吸温度敏感性系数Q10值的影响。结果表明羊草草原土壤呼吸与5cm地温具有很好的指数关系(r2=0.338～0.858,P<0.001～0.08),Q10介于1.15～2.25之间,均值为1.72。Q10值与5cm地温呈负相关关系(r2=0.407),而与0～10cm土壤水分含量呈显著的二次函数关系(r2=0.872,P<0.05)。在较低含水量时Q10值随着水分含量的上升而增大,当土壤水分含量较高时转而减小。以往大多数研究认为Q10值与土壤水分含量呈正相关关系,这可能是土壤水分跨度不足造成的,极端的水分条件对Q10值具有重要影响。Soil respiration rates were measured with static opaque chamber-chromatographic technique in an experimental plot of IMGERS （Inner Mongolia Grassland Ecosystem Research Station）. The effect of soil temperature and moisture on temperature sensitivity of soil respiration was studied. Soil respiration increased exponentially with soil temperature at 5 cm depth （r^2=0.338～0.858,P0.001～0.08）. The temperature sensitivity of soil respiration （Q10） has been widely used in estimating soil respiration rate. A small change in Q10 could cause a significant variation in the modeled soil respiration flux. Therefore,accurately quantifying Q10 and its variability is crucial for estimating ecosystem carbon budget. Our research showed that the Q10 values ranged from 1.15 to 2.25 with an average of 1.72. The Q10 value was negatively correlated with soil temperature at 5 cm depth,however,it related to soil moisture （0～10 cm） with a significant quadratic function （r^2=0.872,P0.05）. In contrast to other reports that Q10 value was positively correlated with soil moisture,our result showed that this positive correlation existed only when soil moisture was relatively low and Q10 decreased when soil moisture nearly reached the field moisture capacity. Extreme soil water conditions will significantly affect the estimate of Q10.

关 键 词：土壤呼吸 温度 水分 Q10 羊草草原 

分 类 号：X144[环境科学与工程—环境科学]