温度、氮输入对洪河湿地CO_2通量的影响

采用静态箱-气相色谱仪法,对洪河湿地CO2呼吸通量进行观测,模拟不同水平氮输入湿地,设计0、20、40、60 g.m-2四种氮水平及秸秆还田处理,探讨不同氮水平对洪河湿地CO2释放的影响。结果表明,7月生态系统呼吸通量高于其他月份,呈现出季节变化的单峰模式。湿地CO2通量与温度具有相关性,其中与5 cm深土壤温度相关性最强,呈指数相关关系。不同氮水平系统呼吸通量与5 cm地温二次相关。氮输入促进了湿地CO2排放,且中氮量输入(N2PK)释放量最多,秸秆还田技术能抑制中氮输入量产生的高呼吸通量。

Effect of temperature and nitrogen addition on CO2 flux from Honghe wetland

CO2 flux was measured monthly over the growing seasons with the closed-chamber technique in the Honghe Wetland.Four N-treatments(0,20,40,60 g·m-2) and straw-return were designed,the effect of different nitrogen application CO2 emission from Honghe wetland was further discussed.The results shows that the CO2 flux was higher in July than other months in the growth season.The CO2 flux was more positively correlated with soil temperature of 5 cm depth than air temperature and soil temperature of 0cm depth,10cm depth,15 cm depth,20 cm depth,there was exponential relationship between CO2 flux and the soil temperature(5 cm).In different nitrogen levels,CO2 fluxes quadratic ally correlated to the temperature at 5 cm depth.The application of fertilizer can improve CO2 flux;ecosystem respiration increased with the increase of nitrogen amount,the maximum soil respiration rate was at N2PK level,and straw-return would decrease the CO2 fluxes of N2PK level.