采用静态箱法测定了常规耕作、免耕留低茬低覆盖、免耕留高茬低覆盖、免耕留低茬高覆盖和免耕留高茬高覆盖5个处理条件下燕麦播种前、生育过程中和收割后土壤CO2、CH4和N2O的排放通量.结果表明:CO2排放通量呈单峰曲线变化,峰值出现在苗期;CH4排放通量多为负值,表现为"吸收",季节性变化不明显;N2O排放规律性不明显.处理间相比,CO2排放通量和CH4吸收通量从大到小依次为常规耕作、免耕留低茬低覆盖、免耕留高茬低覆盖、免耕留低茬高覆盖和免耕留高茬高覆盖;N2O与CO2的排放趋势相反;温室气体综合排放效应与CO2趋势一致.免耕留茬秸秆覆盖减少了CO2排放和CH4吸收,增加了N2O排放,温室气体综合排放效应降低,有利于温室气体减排,但不同处理温室气体排放的长期效应还有待研究.
Greenhouse gas emissions(CO2,CH4 and N2O) under 5 treatments,including conventional tillage,no-tillage with low stubble and low mulch,no-tillage with high stubble and low mulch,no-tillage with low stubble and high mulch,and no-tillage with high stubble and high mulch,were determined using static gas cases on oat production field before seed sowing,during growth,and after harvest.The results showed: CO2 emission fluxes followed a single peak curve,and the peak appeared at the seedling stage.CH4 fluxes were mostly negative,indicating there was a net absorption.Unobvious trend was observed for N2O emission.Of all the 5 treatments,CH4 and CO2 fluxes were descended in an order of conventional tillage,no-tillage with low stubble and low mulch,no-tillage with high stubble and low mulch,no-tillage with low stubble and high mulch,and no-tillage with high stubble and high mulch.N2O and CO2 presented an opposite trend in emission.The integrated emission effects of greenhouse gases were similar to CO2.Coverage with stubbles under no-tillage reduced CO2 emission and CH4 absorption,increased N2O emissions,and greenhouse gas emissions were also increased.But more studies are still warranted to investigate the long-term effects of the different treatments on greenhouse gas emissions.