植物对沼泽湿地生态系统N_2O排放的影响

Influence of Plants on N2O Emission From Wetland Ecosystem

利用静态暗箱/气相色谱法连续3个生长季(2003—2005年)对三江平原小叶章草甸和毛果苔草沼泽N2O排放通量进行野外对比观测试验。结果表明,植物不同生长阶段对湿地生态系统N2O排放通量的影响不尽相同。植物的参与促进了湿地生态系统N2O的排放,2003—2005年生长季小叶章草甸土壤-植物系统N2O排放通量分别是土壤表观N2O排放通量的1.58倍、2.09倍和2.34倍,同期毛果苔草沼泽土壤-植物系统N2O排放通量分别是土壤表观N2O排放通量的1.86倍、1.50倍和1.33倍。3个生长季小叶章草甸N2O排放通量均大于毛果苔草沼泽,这主要是由土壤理化性质的空间变异性以及水文情况的差异造成的。

N2O emission fluxes were measured using the technique of closed opaque chamber and gas chromatography system, in a field experiment carried out during three growing seasons in 2003 - 2005 on a tract of Calamagrostis angustifolia meadow and Carex lasiocarpa marsh. Results show that the influence of wetland plants on N2O emission of the wetland ecosystem varied with their growing stage. Obviously plants participated in and promoted N2 O emission in the wetland. The N2O emission flux from the soil-plant system of Calamagrostis angustifolia meadow was 1.58, 2.09 and 2.34 times as high as the apparent flux from the soil of the system during the three growing seasons, respectively, while that from the system of Carex lasiocarpa marsh was 1.86, 1.50 and 1.33 times as high the apparent flux from the soil of the system. The N2O emission flux of Calamagrostis angustifolia meadow was higher than that of Carex lasiocarpa marsh in all the three growing seasons, which may be attributed to differences between the systems in soil physico-chemical properties and hydrological conditions.