Soil Carbon Release Of Typical Forests In The Qinling Mountains

Global warming is one of the key challenges for human being currently. How to deal with this challenge has become the focus of scientists, officials and the ordinary people. Mitigating increase of CO2 concentration has become the most important problem for all societies. Carbon sequestration of forest soil plays a vital role in global warming. To estimate effects of forest soil on CO2 sequestration, Pinus armandi, Picea asperata and Quercus aliena var. acuteserratathree in the Qinling Mountains were selected. Combining data from field observation and model simulation, dynamics of soil CO2 efflux from different forest types,effects of litter chemical composition on soil respiration and precision of Yasso 07 model were explored. The results were shown as following:(1) Soil respiration rate from different forest types in Qinling Mountains varied with months and generally trended as unimodal curve patterns. The maximum values of soil respiration rate from forests were observed in August. The mean soil respiration rate in three forest types ordered as Picea asperata(2.62±1.06 μmol?m-2s-1)>Quercus aliena var. Acuteserratathree(1.97±0.87μmol?m-2s-1) > Pinus armandi(1.85±0.76μmol·m-2s-1).(2) Soil respiration rate significantly correlated to soil temperature in depth of 0-5 cm soil(R2 ranged from 0.825 to 0.875). Soil temperature is the dominant factor affecting on soil respiration. The values of Q10 from Pinus armandi, Picea asperata and Quercus aliena var. Acuteserratathree were 3.37, 4.38 and 3.60 respectively in the current study and they were higher than the average value of Q10 in China.(3) Significant differences P<0.05)were found from chemical composition content of water soluble(WSC), ethanol soluble(ESC), acid soluble(ASC) and non-soluble(NSC) compounds among the litter types from the the same tree species and similarly in different tree species. The content of ESC and WSC in litter types from broad leaved tree species were higher than that in conifers. However, the content of ASC and NSC in conifers was higher than that in broad leaved tree species. Parameters in Yasso07 model manual can not be used directly when run the model to stimulate soil CO2 efflux in areas outside the European countries.(4) Soil CO2 flux in forests of Pinus armandi, Picea asperata and Quercus aliena var. Acuteserratathree was estimated as 26.71 t?hm-2?a-1, 26.78 t?hm-2?a-1 and 36.21 t?hm-2?a-1 respectively.(5) Comparing simulated values of Yasso 07 to observed data, the error is less than 17%. We concluded that Yasso 07 model could be used to estimate the soil carbon emission in the Qinling Mountains.