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

Using the measurement system of Li-8100 soil CO2 efflux system,We observed the rate of soil respiration of the Cinnamomum 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 3.351,2.145 and 2.154 μmol/m2·s,respectively. The model Rs=aebtWc,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.