鼎湖山针阔叶混交林土壤呼吸的研究

Soil respiration of a coniferous and broad-leaved mixed forest in Dinghushan Mountain, Guangdong Province.

利用静态箱气相色谱法对鼎湖山针阔叶混交林的土壤呼吸速率的季节变化和昼夜变化,进行了为期1年的野外观测研究.自然状态下土壤呼吸速率的年平均值为(400±29)mg(CO2)(m2·h),其中由凋落物分解释放的CO2占土壤总呼吸的年平均比例为42%;土壤呼吸速率与林内气温、地表温度、地下5、10、15和20cm土壤温度都呈显著指数相关,用土壤呼吸速率与温度间的指数模型得出对应于以上各温度的Q10值变动在1.92～2.81之间;土壤呼吸速率与土壤含水量的关系依观测点土壤水分状况不同而有一定差异;土壤呼吸速率的日变化模式在雨季和旱季有明显区别,相对于温带陆地生态系统而言,该林型土壤呼吸速率的日较差较小.

Field experiment was carried out to examine the soil respiration rate by using static chamber-gas chromatograph technique in a coniferous and broad-leaved forest in Dinghushan Mountain Biosphere Reserve for one year. The results show that mean annual soil respiration rate is （400±29） mg（CO2）/（m^2·h）, while CO2 from the litter decomposition accounts for 42 % of the total CO2 emission from the soil surface. Significant relationships are found between soil respiration rate and ambient air temperature, soil temperatures at different depths（the surface, 5 cm depth, 10 cm depth, 15 cm depth and 20 cm depth）, which could be best described by exponential equations. The Q10 values based on air temperature and soil temperature at surface, 5, 10, 15 and 20 cm depth vary from 1.92 to 2.81. The relationships between soil respiration rate and soil water content in the two observation sites vary with the soil water regime. The diurnal pattern of soil respiration rate in the rainy season is distinctly different from that in the dry season. Compared with temperate terrestrial ecosystems, this subtropical forest has a smaller diurnal variation of soil respiration rate.