为研究大气CO2浓度升高对大豆光合能力影响,了解未来全球气候变化后大豆光合生理变化,为气候变化下的大豆生产提供理论依据。本文利用开放式大气CO2富集系统(free air CO2enrichment,FACE)试验平台,研究了大气CO2浓度升高对大豆叶片光合生理和叶绿素荧光参数的影响。结果表明:大气CO2浓度升高后,大豆净光合速率(Pn)增加,气孔导度(Gs)和蒸腾速率(Tr)下降,水分利用效率(WUE)提高。大气CO2浓度升高使CO2同化速率相对应的荧光量子产量(ΦCO2)平均降低了29.8%,光化学淬灭系数(q P)平均降低了4.6%。但大豆叶片PSⅡ最大光化学量子产量(Fv/Fm)、PSⅡ实际光化学量子产量(ΦPSⅡ)和非光化学猝灭系数(NPQ)没有显著变化。
This experiment was conducted in Xinxiang, Henan from June 2013 to June 2014. Total four treatments were designed including farmers ’ common practice （F, 250 kg/hm^2）, 80% F （LF, 200 kg/hm^2）, 80% F＋biochar （LFC） and no fertilizer （CK） to measure the dynamic emissions of CO2 and N2O from a summer maize-winter wheat field by static chamber-gas chromatography method. The results showed that the soil CO2 emission was 21.8-1 022.7 mg/（m^2·h）, and was mainly influenced by soil temperature and moisture content. During the growth of summer maize, the soil CO2 emission was more significantly affected by soil moisture con-tent; and in winter wheat growing season, it was more significantly affected by soil temperature in the top 5 cm. The LF and LFC treatments significantly reduced the soil cumulative CO2 emission, especial y during the growth of winter wheat. Fertiliza-tion and irrigation were the main factors influencing the soil N2O emission. The soil N2O emission during the fertilization period accounted for 73.9%-74.5% and 40.5%-43.6% of the soil cumulative N2O emission during the summer maize-and winter wheat-growing season, respectively. The peak of emission fluxes was determined by fertilization amount, while the occurrence time of emission peak and emission re-duction effect were influenced by irrigation. The LF treatment reduced the soil cu-mulative N2O emission by 15.7%-16.8% and 18.1%-18.5% during the growth period of summer maize and winter wheat, respectively. Reduced nitrogen fertilization is an effective way for reducing N2O emission in intensive high-yielding farmland. Under a suitable nitrogen level （200 kg/hm^2）, the application of biochar showed no significant effect on the soil N2O emission in a short term. The N2O emission factors of the L and LF treatments were 0.60% and 0.56%, respectively. ln the intensive high-yield-ing farmland of North China, reducing the nitrogen application amount is an appro-priate measure to mitigate greenhouse gas emissions without crop yield lo
