氮肥减施对黄淮海地区麦田温室气体排放的影响

Effects of Reduced N Fertilizer Application on Greenhouse Gas Emissions from Wheat Fields in Huang-huai-hai Area

    摘要
  • 摘要: 为探讨玉米秸秆还田条件下,氮肥减量施用对黄淮海区域小麦田温室气体排放的影响,通过田间试验,以农民传统施氮量作为对照(CK),研究了不同氮肥减量施用条件下(比农民传统施氮量减少10%(N1)、20%(N2)、30%(N3)和40%(N4)),麦田温室气体排放量和排放强度的变化。结果表明,不同氮肥减量施用条件下,温室气体(CO2、N2O和CH4)排放通量均具有明显的季节变化。氮肥减量施用显著降低了CO2和N2O的排放量,但对CH4排放量影响不显著。不同氮肥减量施用条件下,CO2和N2O的排放量大小分别为CK>N1>N2>N4>N3和CK>N1>N2>N3>N4,且不同处理间差异显著(p<0.05)。与CK相比,N1、N2、N3和N4处理的CO2排放量分别降低了4.9%、18.7%、36.5%和31.2%;N2O的排放量分别降低了21.9%、32.5%、40.4%和53.5%,并且氮肥使用量与N2O排放量间存在显著正相关关系(r=0.939,p<0.05)。不同氮肥减量施用条件下,CH4吸收量的大小为N2>CK>N4>N3>N1,但不同处理间差异不显著(p>0.05)。氮肥减量施用显著影响麦田温室气体排放强度(Greenhouse Gas Intensity,GHGI),表现为CK>N1>N2>N4>N3,且CK与不同处理间差异显著(p<0.05)。与CK相比,N1、N2、N3和N4处理的GHGI分别降低了7.7%、11.5%、34.6%和19.2%。氮肥施用量比农民传统施氮量减少10%~30%,小麦产量间无显著差异(p>0.05)。从环境和经济效益综合考虑出发,推荐氮肥最佳用量为210 kg·N·hm-2(比农民传统施氮量减少30%)。在该施肥量条件下,小麦产量稳定,且温室气体排放强度最低。该研究结果可为黄淮海区域建立合理的施肥制度提供基础数据。

     

    Abstract: In order to investigate the effects of reduced nitrogen application on greenhouse emission from the wheat fields in Huang-huai-hai area, using static chamber-gas chromatograph technique, we explored the changes of greenhouse gases emissions and intensity from the wheat fields with the different N treatments:CK, a routine amount for farmers, 300 kg·N·hm-2; N1,270 kg·N·hm-2; N2, 240 kg·N·hm-2;N3, 210 kg·N·hm-2 and N4,180 kg·N·hm-2. The results showed that the greenhouse gas fluxes had obvious seasonal changes with the different reduced rates of N fertilizer application. The effects of reduced N fertilizer application on the emissions of CO2 and N2O were significant while that of CH4 was not significant. The cumulative emissions of CO2 and N2O were in the order of CK>N1>N2>N4>N3 and CK>N1>N2>N3>N4, respectively, with the significant difference among different treatments (p<0.05); and that of CH4 was in the order of N2>CK>N4>N3>N1 without significant difference among different treatments (p>0.05).Compared with CK, the cumulative emissions of CO2 with the treatments of N1,N2,N3 and N4 was decreased by 4.9%,18.7%,36.5% and 31.2%,respectively; and the cumulative emissions of N2O with the treatments of N1,N2,N3 and N4 was decreased by 21.9%,32.5%,40.4% and 53.5%, respectively. There was a significant positive correlation between the amount of N fertilizer application and N2O emissions(r=0.939,p<0.05).The effects of reduced N fertilizer application on the greenhouse gas intensity (GHGI) were also significant, and the GHGI was in the order of CK>N1>N2>N4>N3 with significant difference among treatments (p<0.05).Compared with CK, the GHGI with the treatments of N1,N2, N3 and N4 was decreased by 7.7%,11.5%,34.6% and 19.2%, respectively. Wheat yield had no statistical significant difference with reduced N fertilizer rates. Therefore, the optimal rate of N fertilizer was 210 kg·N·hm-2 economically and environmentally, with stable wheat yield and the lowest GHGI. The study would provide the basic data for the establishment of reasonable fertilization system in Huang-huai-hai area.

     

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