施氮水平对稻田土壤温室气体排放的影响

    Effect of nitrogen fertilizer application on greenhouse gas emissions fromsoil in paddy field

    • 摘要: 该研究以江西稻田为研究对象,设置了不施氮对照(N0)、减氮40%(N1)、常规施氮(N2)、增氮50%(N3)等4个处理,采用静态箱-气相色谱法研究了稻田温室气体(N2O、CH4、CO2)的排放通量和速率,并计算了温室气体排放强度及全球增温潜势。结果表明:在晚稻栽培过程中,N2O和CO2的排放通量均出现3次峰值,且都表现为增施氮肥处理高于其他处理,而CH4排放通量仅出现一次峰值;N0、N1、N2的N2O和CO2的总排放量无显著差异(P>0.05),但N3处理下的N2O和CO2的排放量显著高于其他处理(P<0.05);与对照比,N1、N2和N3的CH4总排放量分别提高了58.70%、69.63%、96.15%,净增温潜势分别增加了22.34%、25.34%、52.92%;N3的温室气体排放强度最高,达1.12 kg/kg,显著高于N1和N2。

       

      Abstract: Abstract: Abstract: Paddy fields is the main source of global greenhouse gas emission, and different nitrogen application levels may impact greenhouse gas emissions. The research object is late rice in Jiangxi double cropping rice field, and the treatments include 4 different nitrogen fertilizer levels: control with no nitrogen (N0), nitrogen reduction by 40% (N1), conventional nitrogen (N2), and nitrogen adding by 50% (N3). The emissions and emission rate of nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) were studied by using static chamber - gas chromatograph, and we also computed the global warming potential (GWP) and greenhouse gas intensity (GHGI). The results of the study showed that in the process of late rice growth, the emission flux of N2O and CO2 presented 3 high peaks and all showed that adding nitrogen treatment was higher than other treatments, but the emission flux of CH4 only had a peak. The emissions of N2O under the treatments of N0, N1 and N2 did not have significant difference (P>0.05), only when the nitrogen application amount achieved the maximum value (N3 treatment), the N2O emissions were significantly higher than other treatments. Compared with the N0, the total emissions of CH4 under other 3 treatments (N1, N2 and N3 ) increased by 58.70%, 69.63% and 96.15% respectively, and the GWP increased by 22.34%, 25.34% and 52.92% separately. The GHGI of the N3 was the highest, up to 1.12 kg/kg, and it was significantly higher than N1 and N2. Compared with the conventional fertilizer application, reducing 40% nitrogen fertilizer had no significant effect on rice yield, but it could reduce the total amount of CO2 and CH4, which was beneficial to the energy saving and emission reduction.

       

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