青海果洛黄河源区高寒草甸CO_2释放速率研究

A Study on CO_2 Emission Rate from Alpine Meadow in the Source Region of Yellow River in Guo-luo, Qing-hai Province

以青海果洛黄河源区高寒退化草甸生态系统为对象,应用静态密闭箱-气相色谱法对高寒退化草甸生态系统CO2释放进行了初步研究。结果表明:所选4种不同退化程度高寒草甸,即未退化草甸(A)、轻度退化草甸(B)、中度退化草甸(C)和重度退化草甸(D),其CO2释放速率有明显的日变化特征,日最大排放速率在15∶00-17∶00左右出现,最低值出现于清晨7∶00-9∶00左右,释放白天大于夜晚;(2)CO2释放速率具有明显的季节性变化特征,生长期CO2释放速率明显高于枯黄期,8月为CO2释放高峰期,1月或2月为CO2释放低谷期;(3)CO2释放速率的日变化主要受地表温度和5cm地温制约,季节动态与5cm地温呈显著正相关关系(P<0.01),本研究为进一步进行高寒退化草甸生态系统源江效应的准确估测提供科学依据。

The CO2 emission rate from degraded alpine meadow in the source region of Yellow River in Guo- luo, Qing-hai Province was studied using static chamber-GC method. The results indicate that CO2 emission rate from non-degraded meadow, minor degraded meadow, medium degraded meadow, and heavily degraded meadow showed evident characteristics of daily variations, e.g. peaked at 15：00- 17：00 and minimized at 7 ： 00-9 ： 00, with higher CO2 emission rate at daytime than at night. Furthermore, the CO2 emission also showed a seasonal variation with higher emission rate during the plant growing seasons than at the wilting period. The fastigium of CO2 emission appeared in August and low in January and February. In addition, the daily variations of CO2 emission rate were restricted by soil temperature at 5cm depth and soil surface temperature, and a significant correlation was detected between the seasonal dynamics of CO2 emission rate and soil temperature at 5cm depth （P〈0.01）.