UV-B增强对稻田呼吸速率、CH_4和N_2O排放的影响

Impacts of Enhanced UV-B Radiation on Respiration Rate,CH_4 and N_2O Emission Fluxes from Rice Paddy

于水稻生长季进行室外盆栽试验,人工模拟UV-B辐射增强20%,采用静态箱-气相色谱法测定稻田生态系统的呼吸速率、CH4和N2O排放通量,研究UV-B辐射增强对稻田生态系统呼吸速率、CH4和N2O排放通量的影响.结果表明,UV-B辐射增强没有改变稻田呼吸速率、CH4和N2O排放通量的季节变化规律;与对照相比,平均呼吸速率经UV-B辐射增强处理后从(1 306.83±100.21)mg.(m2.h)-1降至(1 266.23±147.60)mg.(m2.h)-1,降低3.11%;平均CH4排放通量从(2.40±0.48)mg.(m2.h)-1降至(2.02±0.52)mg.(m2.h)-1,降低15.84%.而对照与处理的平均N2O排放通量分别是(217.45±1.72)μg.(m2.h)-1和(229.22±26.02)μg.(m2.h)-1,处理比对照增加5.41%;但以上指标的差异均没有达到显著水平(P>0.05).本研究表明,UV-B辐射增强20%对稻田呼吸速率、CH4和N2O排放通量无显著影响.

To investigate the impacts of enhanced UV-B radiation on respiration rate,CH4 and N2 O emission fluxes from soil-rice system,outdoor pot experiment was carried out during the rice growing season in 2004.The enhanced UV-B radiation treatments were simulated by a 20% increase in its intensity.The gas emission fluxes were measured by static chamber-gas chromatograph method.Results showed that enhanced UV-B radiation（T） did not change the seasonal patterns of respiration rate,CH4 and N2 O emission.Compared to the control,mean respiration rate of T was decreased by 3.11%,from（1 306.83±100.21） mg·（m2·h）-1 to（1 266.23±147.60） mg·（m2·h）-1;Mean CH4 fluxes was decreased by 15.84%,from（2.40±0.48） mg·（m2·h）-1 to（2.02±0.52） mg·（m2·h）-1;Mean N2 O emission fluxes of T was increased by 5.41%,from（217.45±1.72） μg·（m2·h）-1 to（229.22±26.02） μg·（m2·h）-1,while there no significant differences（P0.05）.Our findings suggested that enhanced UV-B radiation had no significant effects on respiration rate,CH4 and N2 O emission fluxes of soil-rice system.