小兴安岭阔叶林沼泽土壤CO_2、CH_4和N_2O排放规律及其影响因子

Emissions of CO_2,CH_4 and N_2O from broad-leaned forested swamp soils in Xiaoxingan Mountains

采用野外静态箱-气相色谱法,研究了小兴安岭典型阔叶林沼泽生长季节土壤CO2、CH4和N2O排放季节变化规律、源/汇功能及主要影响因子。结果表明:①苔草沼泽、毛赤杨沼泽和白桦沼泽生长季节土壤CO2、CH4、N2O排放分别集中在夏季、夏秋季、春夏季,平均排放通量依次为487.89、382.27、514.63 mg.m-2.h-1,1.88、1.03、0.04 mg.m-2.h-1,3.70、58.61、11.73μg.m-2.h-1。②三者生长季节土壤CO2排放通量与气温和0-20 cm土壤温度均呈显著正相关;苔草沼泽CH4排放通量与30-40cm土壤温度呈显著正相关,毛赤杨沼泽CH4排放通量与地表温度呈显著负相关;白桦沼泽N2O排放通量与地表温度呈显著正相关。苔草沼泽N2O排放与水位呈显著负相关;毛赤杨沼泽CH4排放与水位呈显著正相关;白桦沼泽CO2排放与水位呈显著负相关。③三者生长季节土壤均为CO2、CH4、N2O排放源(17.56、13.76、18.53 t.hm-2;67.54、37.05、1.30 kg.hm-2;0.13、2.11、0.42 kg.hm-2),三者CO2排放量相近(5.5%-21.6%);苔草沼泽为CH4的强排放源,毛赤杨沼泽为中排放源,白桦沼泽为弱排放源;毛赤杨沼泽为N2O的强排放源,白桦沼泽为中排放源,苔草沼泽为弱排放源。

The seasonal variation,influening factors and source / sink of emission of greenhouse gases（CO2,N2O and CH4） from marsh,alder（Alnus Jeponica） swamp and birch（Betula platyphella） swamp soils were studied in Xiaoxingan Mountains of China during the growing season of using a static opaque chamber-GC technique.The results showed that： ①The average emission fluxes of CO2,CH4 and N2O from the marsh,Alnus Jeponica-swamp and Betula platyphella-swamp soils were 487.89,382.27,514.63 mg·m-2·h-1,1.88,1.03,0.04 mg·m-2·h-1,3.70,58.61,11.73 μg·m-2·h-1 in growing season respectively,The fluxes of CO2 were higher in summer,CH4 in summer and autumn,and N2O in spring and summer.② Air temperature and soil temperature（≤ 20 cm） were the main factors affecting CO2 emission in the three wetlands soils;Soil temperatures（30-40cm） were the main factors affecting CH4 emission in the marsh soils;Water table and surface soil temperatures were the main affecting factors of CH4 emission in Alnus japonica swamp soil;Water table was the main affecting factors of N2O emission in the marsh soil;surface soil temperature was the main affecting factors of N2O emission in Betula platyphella swamp soil.③During the growing season,All three wetland soils were the sources of CO2,CH4 and N2O（17.56,13.76 and 18.53 t·hm-2·a-1;67.54,37.05 and 1.30 kg·hm-2·a-1;0.13,2.11and 0.42 kg·hm-2·a-1）.their sources of CO2 were very similar（5.5%-21.6%）;the soil of marsh was a strong source of CH4,the soil of Alnus japonica swamp was a medium source of CH4,the soil of Betula platyghella swamp was a weak source of CH4;and the soil of Alnus japonica swamp was a strong source of N2O,the soil of Betula platyghella swamp was a medium source of N2O,the soil of marsh was a weak source of N2O.