Effect Of Warming And Elevated O₃on CO₂Emission From Winter Wheat-Soybean Rotation System

Global warming and ozone pollution are very important global environmental issues today,The major factor leading to global warming is greenhouse gas emissions,and the farmland is an important source of CO2emissions. To investigate the impact of warming and elevated O3radiation on CO2emission from farmland ecosystem, field experiment was carried with one winter wheat growing season and one soybean growing seasons. Seting four treatments included the control treatment(CK), the warming treatment(T), the elevated O3treatment(O) and the warming with the elevated O3compound treatment(OT), and three replicates for each treatment. Measured the CO2emission fluxes by using static dark chamber-gas chromatograph. Analysed the crop biomass, and discussing the influencing laws and possible influencing mechanism of experimental warming and elevated O3on CO2emission from farmland ecosystem, view to offer scientific basis to warming and elevated O3on CO2emission of farmland ecosystem greenhouse gas.The results showed that:T, O, OT did not change the seasonal variation patterns of CO2emission from winter wheat-soybean rotation field, but warming lead to early flowering and shorted the grain filling stage of winter wheat, promoted early maturity of winter wheat. Warming promoted CO2emission, and the ozone suppressed CO2emission.Warming could alleviate and remedy elevated ozone damage to winter wheat and soybeans to some extent, but the warming effect of CO2emission were weaker than the negative effects of O3on CO2emission.In the whole growth period of winter wheat, the mean CO2emission flux sizes of soil and soil-plant system were T> CK> OT> O. Compared with CK, the mean CO2emission flux of wheat soil in winter wheat CO2under T treatments were increased by12.93%(p=0.002), and the soil-plant system increased by14.44% (p=0.013). In the filling stage-maturity, T treatment significantly reduced the mean CO2emission flux.Compared with CK, the mean CO2emission flux fluxes of winter wheat soil CO2under O treatments were reduced by19.94%(p=0.000), and the soil-plant system reduced by20.89%(p=0.000). The mean CO2emission flux of winter wheat soil CO2under OT treatments were reduced by11.46%(p=0.003), and the soil-plant system reduced by14.81%(p=0.012).In the whole growth period of soybean, the mean CO2emission flux sizes of soil and soil-plant system were T> CK> OT> O. Compared with CK, the mean CO2emission flux of soybean soil CO2under T treatments were increased by8.29%(p=0.106), and the soil-plant system increased by18.64%(p=0.001). The mean CO2emission flux of soybean soil CO2under O treatments were reduced by120.27%(p=0.002), and the soil-plant system reduced by31.02%(p=0.000). The mean CO2emission flux of soybean soil CO2under OT treatments were reduced by9.97%(p=0.060), and the soil-plant system reduced by22.01%(p=0.000).In the harvest, the biomass size of winter wheat and soybean were: CK>T>O>OT. Compared with CK, the biomass of winter wheat under T treatment were reduced by20.70%(p=0.003), and the biomass of soybean under T treatment were reduced by10.86%, but which had no significant difference. However, the biomass of winter wheat of the jointing-booting stage, heading-flowering stage, and filling stage under T treatment were increased.The biomass of winter wheat soybean under O treatment were reduced by23.95%(p=0.001) and36.87%(p=0.011). The biomass of winter wheat soybean under OT treatment were reduced by28.94%(p=0.000) and39.03%(p=0.009).