黑河流域高山草甸湿地土壤CO_2通量日变化特征

Daily Variation Process of Soil CO_2 Flux of Alpine Meadow Wetland in Heihe River Basin

采用Li-6400便携式光合作用测量系统连接Li-6400-09土壤呼吸室,在2013年生长季节对黑河流域高山草甸湿地土壤CO2通量进行了野外定位试验,统计分析了水热因子对高山草甸湿地土壤CO2通量特征的影响。结果表明,高山草甸湿地区不同层次土壤的日平均温度差值由土壤表层（0cm）的14.5℃骤降到土壤20cm层的5.8℃,对土壤呼吸有较大的影响;土壤CO2通量日变化特征明显,早晨8：00—10：00维持在较低水平,土壤CO2通量在0.81~1.10μmol/（m2·s）,在11：00开始升高,13：00达到峰值,峰值为3.26μmol/（m2·s）,18：00开始下降,整个过程呈单峰曲线;高山草甸湿地区土壤CO2通量与10cm土壤温度、土壤含水量存在不同程度的正相关关系,表明土壤CO2通量的变化受温度和水分所控制。

We used measuring system of Li-6400 portable photosynthesis to connect soil respiration chamber of Li-6400-09 in the growing season in 2013 to carry out the positioning trial about CO2 flux of alpine meadow wetland soil in Heihe Basin. We analyzed the effect of hydrothermal factors on characteristic of CO2 flux of alpine meadow wetland soil. Results showed that daily average temperature difference of different depth of soil in alpine meadow wetland area went immediately down from 14.5℃ of soil surface to 5.8℃ 20 cm depth, having further effect on soil respiration. Daily variation characteristic of soil CO2 flux is obvious, and keeping in a lower standard at 8：00-10：00 am, CO2 flux of soil is 0.81-1.10 μmol/（m2 .s）, beginning to rise at 11：00, reaching to the peak at 13：00, and the peak is 3.26 μmol/（m2 · s）, beginning to descend at 18：00, the whole process was single-peak curve; soil CO2 flux and soil temperature, soil moisture content in 10 cm depth exist different degrees of positive correlation in alpine meadow wetland areas, showing that the change of soil CO2 flux is controlled by temperature and moisture.