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通过田间试验研究4种耕作方式(秸秆还田、保护性耕作、常规耕作和对照)对巢湖流域圩区农田生态系统冬小麦(Triticum aestivum)田CO2、CH4和N2O排放的影响。采用静态箱-气相色谱法对不同耕作处理下的CO2、CH4和N2O排放通量进行监测。结果表明:(1)不同耕作方式下的CO2、CH4、N2O的排放/吸收具有明显的季节性变化规律,各处理CO2的平均吸收通量之间无显著差异(P<0.05),CH4、N2O的平均排放/吸收通量之间存在显著差异(P<0.05)。(2)乳熟到蜡熟期是白天CO2通量由负值向正值的转换期,和对照相比秸秆还田、保护性耕作、常规耕作的作物产量分别提高了3.3、1.5和3.9倍,且处理之间存在显著差异(P<0.05);(3)各种耕作处理下的CH4排放通量均在-0.3~0(mg·m-2·h-1)之间波动,与对照比较,保护性耕作累计吸收量要高16个百分点,相关分析显示,除秸秆还田外,各处理的CH4的吸收率与5 cm土温之间呈显著正相关;(4)N2O是麦田生态系统主要排放源,保护性耕作与对照相比N2O排放率降低了12%,而秸秆还田、常规耕作与对照相比N2O排放率分别增加了35%和61%;(5)与对照相比,秸秆还田、保护性耕作、常规耕作的N2O单位产量排放量分别降低了4.31μg·g-1、3.36μg·g-1和2.70μg·g-1。
Effects of four farming methods (straw returning, conservation tillage, conventional tillage and comparison) on CO2, CH4 and N2O emissions in winter wheat (Triticum aestivum) field in polder areas of Chaohu Lake basin were studied through field experiments. Static box-gas chromatography was used to monitor the CO2, CH4 and N2O fluxes under different tillage treatments. The results showed that: (1) The seasonal variation of CO2, CH4 and N2O emissions under different tillage patterns showed no significant difference (P <0.05), and the average fluxes of CH4, N2O There was a significant difference (P <0.05) between the mean emission / absorption fluxes. (2) The milk ripening to wax ripening stage was the conversion period from negative to positive of CO2 fluxes during the daytime. Compared with the control, the crop yields of straw returning, conservation tillage and conventional tillage increased by 3.3, 1.5 and 3.9 times respectively (P <0.05). (3) CH4 flux fluctuated between -0.3 ~ 0 (mg · m-2 · h-1) under various tillage treatments, compared with the control Compared with the control, the accumulative absorption of conservation tillage was 16 percentage points higher. Correlation analysis showed that there was a significant positive correlation between CH4 absorption rate and 5 cm soil temperature except for straw returning. (4) Compared with the control, the main emission source of the system and conservation tillage reduced the N2O emission rate by 12% compared with the control. However, the N2O emission rates increased by 35% and 61%, respectively, compared with the control; and (5) Compared with the control , Straw mulching, conservation tillage, and conventional tillage decreased 4.31 μg · g-1, 3.36 μg · g-1 and 2.70 μg · g-1, respectively.