不同施氮措施对冬小麦农田土壤温室气体通量的影响

Effect of Different Nitrogen Application Measures on Soil Greenhouse Gases Fluxes in Winter Wheat Cropland

农田生态系统是大气中温室气体重要的排放源,其温室气体排放量占全球人为活动产生总量的10%-12%,减少农田生态系统温室气体的排放,对于减少温室气体排放总量,缓解全球变暖具有积极的作用。以河南省平顶山市冬小麦农田为研究对象,设置5种施氮措施,分别为:尿素+脲酶抑制剂(U+HQ)、尿素+硝化抑制剂(U+DCD)、尿素+脲酶抑制剂+硝化抑制剂(U+HQ+DCD)和包膜尿素(PCU),并以尿素(U)为对照,采用静态暗箱-气相色谱法测定分析了冬小麦栽培关键阶段N_2O、CO_2和CH_4通量及其累积通量。研究表明,3种温室气体通量均随小麦生长呈先降低后升高再降低的趋势。与U相比,其他4种施氮措施均减少N_2O累积通量,减排效果呈U+DCD>PCU>U+HQ>U+HQ+DCD的规律,其中U+DCD及PCU减排效果较显著,降幅分别为44.44%和20.99%(P<0.05);除U+HQ外,U+DCD、U+HQ+DCD和PCU均显著降低了CO_2的累积排放量(P<0.05),减排效果呈U+HQ+DCD (42.29%)>PCU (40.84%)>U+DCD (34.78%)>U+HQ (6.07%)的规律;其他4种施氮措施均显著降低了CH4的累积吸收量(P<0.05),其中U+DCD和U+HQ+DCD降幅较大,分别为48.21%和49.40%(P<0.05)。与U相比,其他4种施氮措施均显著降低了温室气体全球增温潜势,减排效果呈PCU>U+HQ+DCD>U+DCD>U+HQ,降幅分别为38.29%、36.64%、36.03%、6.54%(P<0.05)。不同施氮措施对小麦产量有显著影响(P<0.05),呈U+DCD>U+HQ>U>PCU>U+HQ+DCD的规律。综合分析表明,普通尿素配施硝化抑制剂可以有效降低温室气体排放并提高冬小麦产量。

Agricultural ecosystem is the most important emission source of atmospheric greenhouse gas(GHG)and its production amount accounts for 10%to 12%of the total global anthropogenic GHG.Cropland management influences GHG emissions,which can be reduced by adopting conservation practices,such as inhibitor applications,coated slow-released fertilizer additions,tillage practices,irrigation,residue management,and so on.GHG reduction from agricultural ecosystem plays a positive role in mitigating global warming.Therefore,a winter wheat field in Pingdingshan city,Henan province were selected as the research object.Five kinds of nitrogen(N)application measures,i.e.,urea+urease inhibitor(U+HQ),urea+nitrification inhibitor(U+DCD),urea+urease inhibitor+nitrification inhibitor(U+HQ+DCD),polymer coated urea(PCU)and urea(U)as the control,were set up.Nitrous oxide(N 2 O),carbon dioxide(CO 2)and methane(CH 4)fluxes,as well as their cumulative amounts were analyzed in the main cultivation stages of winter wheat by using the static opaque chamber-gas chromatogram techniques.The results showed that three kinds of greenhouse gases fluxes had seasonal fluctuation,tended to decrease first then increase and final decrease.Compared with U,the other four N application measures all reduced cumulative N 2 O flux,tended to U+DCD >PCU >U+HQ >U+HQ+DCD,among which U+DCD and PCU had significantly mitigated its emission,decreased by 44.44%and 20.99%(P<0.05).Moreover,U+DCD,U+HQ+DCD and PCU except for U+HQ had significantly reduced the cumulative CO 2 flux(P<0.05),the mitigation rates tended to U+HQ+DCD(42.29%) >PCU(40.84%) >U+DCD(34.78%) >U+HQ(6.07%).Compared with U,the other four N application measures also significantly reduced cumulative CH 4 absorption(P<0.05),among them,U+DCD and U+HQ+DCD decreased significantly by 48.21%and 49.40%(P<0.05).Compared with U,the other four N application measures all significantly reduced global warming potential,the mitigation rates were as follow,PCU >U+HQ+DCD >U+DCD >U+HQ,decreased by 38.29%,36.64%,36.03%and 6.54%(P<0.05),respectively.Wheat yields were impacted by different N application measures(P<0.05),tended to U+DCD >U+HQ >U >PCU >U+HQ+DCD.Comprehensively,common urea combined with nitrification inhibitor can effectively mitigate greenhouse gas emissions and increase winter wheat yield.