摘要
选择小兴安岭山区毛赤杨(Alnus sibirica)沼泽为研究对象,利用静态暗箱-气相色谱法,研究两个生长季内(2007年和2008年)沼泽湿地在自然状态下CH4、N2O排放通量的变化规律及其主要影响因素,以及在不同采伐干扰(皆伐、45%择伐)方式下,CH4和N2O排放通量的变化过程.结果表明,2007年CH4和N2O平均排放通量分别为1.03mg.m-.2h-1和58.56μg.m-.2h-1,2008年分别为20.57mg.m-2.h-1和17.41μg.m-.2h-1;CH4排放高峰期均发生在夏、秋两季,N2O排放规律不明显.皆伐沼泽和45%择伐沼泽CH4平均排放量分别为597.06、237.05μg.m-2.h-1,N2O平均排放量分别为35.84、114.51μg.m-.2h-1;与天然沼泽相比,CH4排放量明显下降,N2O排放通量明显升高.水位是CH4排放的主要影响因子,但当水位达到一定高度时不再成为限制因子,土壤温度与CH4排放相关性显著,相对较低水位与相对较高土壤温度有利于N2O排放;积水水位是影响沼泽不同年份CH4和N2O通量排放差异的主要影响因子,采伐引起的土壤温度和水位的变化是干扰地与对照地CH4和N2O排放产生差异的主要原因.
Methane （CH4） and nitrous oxide （N2O） emissions from an Alnus sibirica swamp were studied using a static opaque chamber and gas chromatography during the growing season of 2007 and 2008 in the Xiaoxing＇an Mountains. The effects of cutting （ clear cutting, selective cutting with an intensity of 45% ） on CH4 and N2O emission from the Alnus swamp were also measured. The results showed that： the mean fluxes of CH4 and N2O in 2007 were 1.03 mg·m^-2·h^-1 and 58. 56μg·m^-2·h^-1,respectively; while those in 2008 were 20.57 mg·m^-2·h^-1and 17.41μg·m^-2·h^-1 , respectively. The maximum CH4 fluxes occurred in the summer and autumn, but there was no clear seasonal pattern for N20. The mean CH4 fluxes due to clear cutting and selective cutting were 597.06 and 237.05 μg·m^-2·h^-1, and those of N20 were 35.84 and 114.51μg·m^-2·h^-1, respectively. The CH4 fluxes decreased due to the disturbances, while the N20 flux increased. Water table level was the main factor for CH4 emission, but soil temperature became the limiting factor when the water level reached a certain height. Low water level and high soil temperatures favored N2O emission. The water level significantly contributed to the annual variations of CH4 and N2O emission. Changes in soil temperature and water level resulting from the disturbances were the main reason for the differences of CH4 and N2O fluxes between disturbed and control plots.
出处
《环境科学学报》
CAS
CSCD
北大核心
2009年第12期2642-2650,共9页
Acta Scientiae Circumstantiae
基金
国家自然科学基金项目(No.30670349)~~
