城市森林土壤表面CO_2通量

Soil Surface CO_2 Flux of Urban Forest

为了揭示城市不同植被类型的土壤表面CO2通量的日动态(Rs)、季节动态及其对气温变化的响应,利用土壤呼吸自动测定系统(Li-8100)对上海不同植被类型Rs进行了连续一年的定位观测研究。结果表明:常绿林、灌木林、落叶林的Rs分别为2.7μmol/(m2.s)、2.18μmol/(m2.s)、1.54μmol/(m2.s),不同植被类型的Rs差异显著。城市不同植被类型的Rs日动态和季节动态均表现为一个单峰型的模式,与温度日和季节动态变化模式基本同步,表明温度是影响土壤呼吸比较重要的因子。指数模型能够较好地揭示不同植被类型对温度变化的响应模式。不同植被类型的Q10值介于2.05~2.39之间,说明植被类型会影响到Rs对温度变化的敏感程度。

Soil surface CO2 flux(Soil respiration,Rs) was measured in situ utilizing the automated soil efflux system(Li-8100) in order to know the daily and seasonal dynamics and the response of soil respiration to air temperature.The results showed that Rs rates of the evergreen forest,brush forest and hardwood forest were 2.7μmol/(m2·s),2.18μmol/(m2·s),and 1.54μmol/(m2·s) respectively,and the Rs of different vegetations were significantly different.The daily and seasonal dynamics of Rs of urban forests in urban region were both peak models.The variation of soil respiration was roughly consistent with that of temperature,which showed that temperature was an important factor in influencing soil respiration.The relationship between soil respiration and temperature could be expressed as exponential curve.The temperature sensitivity coefficients of soil respiration(Q10 value) were different among different vegetations and were between 2.05~2.39,which showed that vegetation types influence the sensitivity of soil respiration to the variation of temperature.