根与凋落物对樟树人工林土壤呼吸的影响

Impact of Root and Litterfall on Soil Respiration in Cinnamomum camphora Plantation

采用LI-8100开路式土壤C通量测定系统,对湖南省森林植物园10~20年樟树人工林土壤呼吸速率进行了为期1年的观测。结果表明：土壤呼吸CO2排放速率最大值在7月、8月,最小值出现在2月和3月,表现出单峰曲线的月动态变化趋势。对照、去除凋落物及去根3种处理的土壤呼吸速率范围分别为0.39~9.34、0.29~5.77、0.43~6.22μmol/m2·s,年均土壤呼吸速率分别为3.351、2.145和2.154μmol/m2·s。采用双因素关系模型（Rs=aebtWc）,结果 优于仅考虑土壤温度或土壤湿度的单因素关系模型;土壤温度和湿度共同解释了2010年不同处理方式土壤呼吸速率季节变化的95.2%~97.6%。对照、去根及去除凋落物处理的土壤呼吸Q10值分别为1.998、1.744、1.815,证明了根及凋落物对森林土壤呼吸起着一定的影响作用。

Using the measurement system of Li-8100 soil CO2 efflux system,We observed the rate of soil respiration of the Cinnamomunm camphora forest plantation which had been 10 to 20 years in Forestry Park of Changsha, Hunan.The results showed that the dynamic of the mean soil respiration rates per month displayed the single peak curve basically. The maximum value appeared between July and August ,and the minimum value appeared between February and March. Soil respiration rate ranges of the control plots ,root exclusion and litter exclusion were 0.39-9.34,0.29-5.77 and 0.43 -6.22 μmol/m2. s, respectively, The annual mean soil respiration rates were 3.35 1, 2.145 and 2.154μmol/m2. s, respectively. The modeI Rs = aebtWe, neither soil temperature nor soil water content could explain the seasonal variation of soil respiration well.Soil temperature and soil water content together could explain 95.2% -97.6% of seasonal variation in soil respiration rates.The Q10 values of the soil respiration in the control plots ,root exclusion and litter exclusion were respectively 1.998,1.744 and 1.815.The results indicated that root and litterfall were important factors in affecting soil CO2 efflux in forests.