Soil Respiration Characteristics And Stem Respiration Characteristics Of Typical Communities In Growing Season At XiaoXing'An Mountain, China

In order to ascertain the carbon emission rate of total soil respiration (Rt), including soil microbial respiration (Rh), root respiration (Rr), li tterfall re spiration (R1) and their r esponse influence on soil temperature and water con tent of four typi cal p rimary Korean pine forest communities, the different vegetation t ypes communities and the birch during different succession stage at the X iaoxing'an m ountain, t renching-plot a nd i nfrared ga s exchange analyzer ap proaches w ere us ed to measure soi 1 CO2 during the growing season. The results indicated that Rt, Rh, Rr and R1 of four primary Korean pine communities changed obviously seasonally. Rt, Rh, Rr of four communities were higher in July and September, lower in June and October. On average, contribution of Rhto Rt was 58.8%, ranked first and the second was Rr(26.5%), the third was R1(12.5%). There was significant correlation between Rt and soil temperature in 5cm depth in all plots during growing season (p<0.01). Q10 of Rr and Rh was 2.88 and 2.23, respectively showing that the r oot re spiration was m ore sensitivity to soil temperature tha n that of microbial re spiration. Among the va rious c omponents of s oil respiration of the birch species of different succession stages, Rh of Larch - Birch and near mature birch forest has the same peak value time with Rt, while the over mature Birch forest later about 10 days, i ndicating Rh have a significant impact on Rt. Birch communities at different su ccession st ages, an average Q10 of s oil m icrobial respiration (2.51)>total s oil respiration (2.27)>root respiration (2.13), indicating that Rh has the most sensitive response to soil te mperature. The contribution of each c omponent of Birch communities at dif ferent succession stages to soil re spiration Rt followed by:Rh(47.51%)> R1(27.89%)> Rr (24.28%).Among different ve getation t ypes,the soil re spiration peak value time of Betula costata and Picea sp.-Abies nephlolepis forest appeared in August, while the Larch, larch and weed in t he S eptember. Among different vegetation t ypes,an average Q10 of the root respiration (2.53)>total s oil re spiration (2.37)> soil m icrobial r espiration (2.26). The contribution of each component of different vegetation types to soil respiration Rt followed by: Rh(51.57%)> R1(28.82%)> Rr (21.09%).The maximum value of Betula costata and Korean pine stem respiration rate appeared at 11:00-13:00, the minimum value occurred at 07:00-09:00. There w as s ignificant c orrelation between tree trun k temperature a nd respiration rate(R2=0.534), the average maintenance respiration of different DBH Betula costata to total stem r espiration was 57.89%,the DBH of Betula costata the hi. gher, the gr eater the Rm,accordingly 61.17% and 54.61%. the Q10 of Korean pine stem respiration ranked between 2.67-2.89.