Soil respiration characteristics in the clear-cutting site of Quercus aliena var. acuteserrata forest in Xiaolong Mountain in Qinling Mountains

By using Li-6400 portable photosynthesis system with soil chamber,the soil respiration rates( R s) of Quercus aliena var. acuteserrata forest land( control site) and their clear-cutting site were measured in Xiaolong Mountain of Qinling Mountains from May 2011 to April 2012 to understand the diurnal and monthly dynamics of soil respiration rate and the influences from soil temperature,soil moisture,soil physical and chemical properties. The results showed that both diurnal and monthly dynamics of soil respiration rate presented a single-peak curve,similar to the variation of soil temperature at the clear-cutting and control sites. During the study period,the maximum monthly mean values of soil respiration rate at the clear-cutting and control sites occurred in July( 4. 63 and 4. 01 μmol·m-2·s-1,respectively) and the minimum values presented in February( 0. 10 and 0. 30 μmol·m-2·s-1,respectively). Soil respiration rate in 4-6 months after clearcutting was higher than at the control site,and became lower afterwards. 89. 6%-90. 8% of soil respiration rate variation was interpreted by the multiple regression models of soil temperature,soil moisture and their interaction at the clear-cutting site,and 94. 7%-95. 5% at the control site. The Q 10 values computed by exponential equations were 3. 47-4. 22 and 3. 54-3. 96 at the clear-cutting and control sites,respectively. The C fluxes at the clear-cutting and control sites were 344. 8 and 512. 9 g·m-2annually,and 24. 2 and 40. 9 g·m-2in winter,respectively.