Effects Of Simulated Experimental Warming And Acid Rain On CO₂and CH₄Fluxes From Winter Wheat And Soybean Farmland

Global warming and acid rain are very important atmospheric environmental issues today, which have been concerned by scholars at home and abroad, and farmland ecosystem plays an important role in the global greenhouse gases budget. To investigate the influence of diurnal warming and acid rain on CO2fluxes and CH4from farmland ecosystem, Field experiments were adopted which include two soybean growing season and one winter-wheat growing season. And the entire experimental field was divided into four equal-area sub-blocks, which are diurnal warming (T), without warming or acid rain(CK), acid rain(S) and diurnal warming with acid rain (ST). Infrared radiation heating pipes are used for diurnal warming which heated for24hours every day, Surface of leaves and soil raised about two degrees. PH value of acid rain is1.0, watering once every two weeks. CO2and CH4fluxes from soil and crop-soil system were analyzed by static chamber-gas chromatography method. This study will provide the base to evaluate the ecological effect of diurnal warming and acid rain objectively, as well as to estimate the regional farmland greenhouse gas emission and its’long term tendency in farmland ecosystem under diurnal warming and acid rain.Results indicated that:T, S, and ST compared with CK, did not change the seasonal pattern of CO2and CH4fluxes from soil and soil-winter wheat system. In the respect of CO2emission fluxes from soil-winter wheat system, T and ST significantly raised mean CO2emission fluxes (MCEF) during reviving stage, however, S had no significant difference in MCEF with CK. In the respect of CH4fluxes, T significantly declined mean CH4fluxes (MCUF), none of S and ST had significant difference compared in MCUF with CK. An obvious daytime variation of CO2fluxes was observed in soil-winter wheat system, which did not changed by treatment of diurnal warming. And CH4fluxes showed random daytime variation from soil-winter wheat, which also did not changed by treatment of diurnal warming.In the respect of CO2fluxes from soil, T significantly raised MCEF during maturity stage, ST significantly raised MCEF during jointing-booting stage, However, S had no significant difference compared with CK in MCEF. In the respect of CH4uptake fluxes, S significantly raised MCUF during filling and maturity stage, however, T and ST had no significant difference in MCUF.T, S, and ST compared with CK did not change the seasonal pattern of CO2and CH4fluxes from soil and soil-soybean system. In the respect of CO2emission fluxes from soil-soybean system, T significantly raised MCEF during pod filling-maturity stage and whole growth, There was no significant difference between S and ST in MCEF. In the respect of CH4uptake fluxes, none of T, S and ST had significant difference compared with CK in mean CH4uptake fluxes (MCUF). An obvious daytime variation of CO2fluxes was observed in soil-soybean system, which did not changed by treatment of diurnal warming. And CH4fluxes showed random daytime variation from soybean-soil system, which also did not changed by treatment of diurnal warming.In the respect of CO2fluxes from soil, ST significantly raised MCEF during flowering-pod stage, however, S and T had no significant difference compared with CK in MCEF. In the respect of CH4fluxes, S significantly raised MCUF during flowering-poding stage, however, T and ST had no significant difference in MCUF.