【作者】 吴光磊；

【导师】 王振林； 蒋高明；

【作者基本信息】 山东农业大学 ， 作物栽培学与耕作学， 2012， 博士

【摘要】 冬小麦-夏玉米一年两作体系是近年来各地在“吨粮田开发”中广泛采用的种植方式。基于提高该体系产量和氮肥利用率的目的，本试验在大田条件下，以冬小麦-夏玉米一年两作体系为研究对象，在冬小麦季设置7个施氮量水平：0kg·hm-2(N0)、56.25kg·hm-2(N1)、112.5kg·hm-2(N2)、168.75kg·hm-2(N3)、225kg·hm-2(N4)、281.25(N5)kg·hm-2、337.5kg·hm-2(N6)，2个追氮时期处理：拔节期（S1）、拔节期+开花期（S2），采用15N同位素示踪技术，从生理学、生态学角度研究了麦季氮肥运筹对冬小麦、夏玉米氮素积累、分配、转运、利用、损失、残效和籽粒产量形成的调控效应，旨在为冬小麦-夏玉米一年两作体系合理氮肥运筹方案的制定提供理论依据和技术支持。1麦季氮肥运筹对冬小麦、夏玉米氮素积累和转运的影响随施氮量增加，冬小麦开花期植株氮素积累量、成熟期籽粒和营养器官氮素积累量不断提高，但N5与N6处理无显著差异；夏玉米成熟期籽粒氮素积累量不断增加，但在N4基础上增施25%~50%氮肥对夏玉米成熟期籽粒氮素积累量无显著影响。与拔节期追氮相比，拔节期+开花期追氮提高了冬小麦开花期氮素总积累量、成熟期N3和N4条件下的籽粒氮素积累量和各施氮量条件下夏玉米的籽粒氮素积累量。随施氮量增加，转运氮素的贡献率先升后降，花后籽粒积累氮素的贡献率反之；在N4基础上增施25%~50%氮肥对营养器官贮藏氮素转运量无显著影响；同一施氮量条件下，叶片贮藏氮素的转运量及其贡献率最高，其次为茎秆+叶鞘，颖壳+穗轴中的最低。2麦季氮肥运筹对冬小麦、夏玉米吸收利用不同来源氮素的影响随施氮量增加，冬小麦开花期不同器官肥料氮积累量的提高幅度为叶片>茎秆+叶鞘>颖壳+穗轴，表明增施的氮肥更多的分配在叶片中；成熟期植株中肥料氮积累量及其分配比例表现为N5、N6>N4、N3，土壤氮的反之，表明在N4基础上增施25%氮肥有利于提高冬小麦成熟期对肥料氮的积累，但再增施25%无显著效果。同一施氮量条件下，叶片和茎秆+叶鞘中肥料氮和土壤氮的转运量高于颖壳+穗轴；转运率以叶片的最高，其次为茎秆+叶鞘，颖壳+穗轴的最低。随麦季施氮量增加，夏玉米开花期植株中来自麦季肥料氮的量显著提高，麦季肥料氮的比例为3.81%~16.59%；麦季施氮量在168.75(N3)~337.5kg·hm-2(N6)范围内时，夏玉米对麦季氮肥的利用率为2.43%~8.05%；麦季施氮量在N4基础上增施25%对夏玉米籽粒中麦季肥料氮的积累量无显著影响，但有利于提高残留氮肥的利用率，继续增施25%氮肥则显著降低麦季和周年氮肥利用率。3麦季氮肥运筹对冬小麦-夏玉米一年两作体系农田氮素损失的影响冬小麦基肥和拔节肥后的氨挥发速率以施肥后第2天最高，之后下降，但会因降雨出现新的峰值。随麦季施氮量增加，夏玉米基肥后的氨挥发速率和积累量不断提高，至大口期，不同处理氨挥发速率和积累量的差异减小；拔节期+开花期追施氮肥提高了夏玉米基施氮肥后的氨挥发速率，但对玉米大口期的氨挥发速率和积累量无显著影响。随麦季施氮量增加，小麦和玉米成熟期深层土壤硝态氮含量显著增加，加剧了硝态氮淋溶损失。与麦季拔节期追氮相比，拔节期+开花期追氮提高了冬小麦成熟期0~40cm土层土壤中的硝态氮含量，减少了夏玉米成熟期60~140cm土层的硝态氮含量。4麦季氮肥运筹对冬小麦、夏玉米碳代谢的影响拔节期追氮条件下，在N4基础上增施25%氮肥显著增加了冬小麦和夏玉米成熟期籽粒干物质积累量，提高了冬小麦旗叶和夏玉米穗位叶的光合速率，增加了灌浆初期籽粒可溶性糖含量。拔节期+开花期追氮条件下，在N4基础上增施25%氮肥对冬小麦和夏玉米籽粒干物质积累、冬小麦营养器官贮藏干物质的转运、旗叶光合速率均无显著影响。同一施氮量条件下，与麦季拔节期追氮相比，拔节期+开花期追氮提高了冬小麦开花后籽粒干物质积累量及其贡献率，延长了光合速率高值持续期，促进了夏玉米成熟期籽粒和营养器官干物质积累量的增加。5麦季氮肥运筹对冬小麦、夏玉米产量的影响拔节期追氮条件下，麦季施氮量在N4基础上减施降低了冬小麦和夏玉米的生物产量与籽粒产量，增施25%氮肥提高了冬小麦和夏玉米的生物产量，但对籽粒产量无显著促进作用；拔节期+开花期追氮条件下，在N4基础上增施25%~50%氮肥对冬小麦和夏玉米生物产量和籽粒产量均无显著促进作用，增施的肥料为无效投入。同一施氮量条件下，与拔节期追氮相比，拔节期+开花期追施氮肥对冬小麦生物产量无显著促进作用，但显著提高了冬小麦N3和N4条件下的籽粒产量，促进了夏玉米生物产量与籽粒产量的增加。6麦季氮肥运筹对冬小麦、夏玉米氮肥利用率的影响同一追氮时期条件下，随麦季施氮量增加，冬小麦氮肥农学利用率和氮肥偏生产力显著降低，夏玉米的不断提高；周年氮肥农学利用率先升后降，以N4处理最高，周年氮肥偏生产力不断降低。与拔节期追氮相比，麦季拔节期+开花期追氮不仅提高了冬小麦和夏玉米的氮肥农学利用率与氮肥偏生产力，且促进了夏玉米对麦季残留氮肥的利用。综合冬小麦和夏玉米籽粒产量、氮肥农学利用率、氮肥偏生产力和氮肥利用率结果，冬小麦季施氮225kg·hm-2，在拔节期+开花期追施氮肥，是本试验条件和种植模式下的最佳麦季氮肥运筹模式。更多还原

【Abstract】 Wheat and maize cropping system was widely used in recent years to achieve one ton ofgrain yield. This study was conducted in field trial in winter wheat and summer maize cropingsystem to investigate how to improve utilization efficiency of nitrogen fertilizer in thiscropping system. Seven nitrogen fertilizer application rate, including0kg·hm-2(N0)、56.25kg·hm-2(N1)、112.5kg·hm-2(N2)、168.75kg·hm-2(N3)、225kg·hm-2(N4)、281.25kg·hm-2(N5)、337.5kg·hm-2(N6), and two nitrogen topdressing stage including jointingstage (S1) and jointing and anthesisstage (S2) were selected, applying with15N isotope tracertechnique, to explore the effects of nitrogen management in winter wheat season on nitrogenaccumulation, distribution and translocation, and regulation effect on grain formation fromthe perspective of physiology and ecology, aiming to provide a theoretical basis and technicalsupport for the formulation of reasonable nitrogen management.1Effects of nitrogen management in wheat season on nitrogen accumulation anddistribution of winter wheat and summer maizeNitrogen accumulation of winter wheat atanthesis, of grain at maturity and of vegetativeorgans continually increased with elevating nitrogen application rate. While treatment N5andN6showed no significant difference, indicating the elevated nitrogen amount in treatment N6,compared to treatment N5, did not improve nitrogen accumulation of winter wheat. Nitrogenaccumulation of summer maize grain at maturity showed the trend: N6、 N5、N4>N3>N2>N1, indicating adding25%~50%of nitrogen on the basis of N4in wheat seasondid not significantly influent the nitrogen accumulation of summer maize grain at maturity.Compared with topdressing at jointing stage, topdressing at jointing andanthesis improvednitrogen accumulation of winter wheat atanthesis, nitrogen accumulation of grain at maturityin treatment N3and N4condition, and nitrogen accumulation of summer maize grain,indicating S2treatment improved the nitrogen accumulation in winter wheat and summermaize cropping system, compared to S1treatment. 2Effects of nitrogen management in wheat season on nitrogen uptake from differentsources in winter wheat and summer maizeWith increasing nitrogen application, increment of nitrogen accumulation from soil indifferent wheat organs inanthesis showed the trend leaf>stem+leaf sheath>husk+ear axis,indicating the elevated nitrogen application was more distributed to leaf. Nitrogenaccumulation from fertilizer and distribution proportion of wheat at maturity showed the trendN5, N6>N4, N3, and nitrogen accumulation from soil showed the contrary order, indicatingadding25%of nitrogen on the basis of N4treatment improve the nitrogen accumulation fromfertilizer at wheat maturity, but no influence with adding50%of nitrogen on the basis of N4treatment. Under the same nitrogen application rate, translocation of nitrogen derived fromfertilizer and soil in leaf and stem+leaf sheath was higher than that in husk+ear axis, withthe highest translocation proportion in leaf, followed by stem+leaf sheath, the lowest in husk+ear axis. Translocation of nitrogen derived from soil in leaf, stem+leaf sheath and husk+ear axis was higher than that derived from fertilizer in N3, N4, N5treatment; however, N6showed the contrary order, indicating adding50%of nitrogen on the basis of N4treatmentinhibited the translocation of nitrogen derived from soil in vegetative organs to grain, notfavorable for the improvement of nitrogen harvest index.With increasing nitrogen application in wheat season, nitrogen of summer maize plantatanthesis, which derived from fertilizer applied in wheat season, enhanced significantly andthe proportion of nitrogen derived from fertilizer applied in wheat season accounted for3.81%~16.59%. Nitrogen of summer maize grain, which derived from fertilizer applied inwheat season showed the trend N6, N5>N4>N3and N6>N5>N4>N3in leaf+stem sheathand husk+ear axis, indicating adding25%~50%of nitrogen on the basis of N4applicationrate in wheat season did not significantly influent the accumulation of nitrogen derived fromfertilizer applied in wheat season in summer maize grain but adding50%of nitrogenimproved the nitrogen accumulation in vegetative organs.Nitrogen utilization efficiency in wheat season showed the trend N3, N4, N5>N6and N5,N6>N4>N3, and N4, N5>N3>N6in terms of utilization efficiency of residual nitrogen andnitrogen utilization efficiency of the whole year, respectively, indicating adding or subtracting25%of nitrogen on the basis of N4in wheat season did not significantly influent nitrogenutilization efficiency of wheat plant but adding25%of nitrogen improved utilizationefficiency of residual nitrogen and adding more25%of nitrogen significantly decreasednitrogen utilization efficiency in wheat season and of the whole year. 3Effects of nitrogen management in wheat season on nitrogen loss in winter wheat andsummer maize cropping systemThe ammonia volatilization rate reached the highest in the second day after the basalapplication and topdressing of nitrogen, and then declined. However, a new peak wouldappear due to rainfall and the peak level related to the volume of rainfall. Under the samenitrogen application condition, the highest ammonia volatilization rate and accumulation inS1was higher than those in S2after topdressing in high level nitrogen application treatments.With increasing nitrogen application rate in wheat season, ammonia volatilization rate andaccumulation after basal application of nitrogen in summer maize season continually rose andthe differences of ammonia volatilization rate and accumulation between treatmentsdiminished continually after topdressing at male tetrad stage. Topdressing at jointing andanthesis stage in wheat season enhanced ammonia volatilization rate after basal application insummer maize season but did not significantly influent the ammonia volatilization rate andaccumulation after topdressing at male tetrad stage.With increasing nitrogen application in wheat season, nitrate nitrogen content in deep soilsignificantly increased at maturity in wheat and maize season, resulting in nitrogen lossthrough leaching. Compared to topdressing at jointing stage, topdressing at jointing andanthesis stage increased nitrate nitrogen content in0~40cm soil layer at maturity in wheatseason, and decreased nitrate content in60~140cm soil layer at maturity in summer maizeseason.4Effects of nitrogen management in wheat season on carbon metabolism in winterwheat and summer maizeUnder the condition of topdressing at jointing stage, adding25%of nitrogen on the basis ofN4significantly increased dry matter accumulation of grain at maturity in wheat and maize,improving the increment of grain dry matter accumulation after flowering in winter wheat butno significant effect by adding more nitrogen application. Under the condition of topdressingat jointing and anthesis stage, adding25%of nitrogen on the basis of N4did not significantlyinfluent the grain dry matter accumulation in winter wheat and summer maize andtranslocation of dry matter in vegetative in wheat.Under the same nitrogen application rate, compared to topdressing ate jointing stage inwheat season, topdressing ate jointing and anthesis stage enhanced dry matter accumulationof grain after flowering and its contribution proportion, and improved dry matteraccumulation of grain and vegetative organs at maturity in summer maize. 5Effects of nitrogen management in wheat season on yield of winter wheat and summermaizeUnder the condition of topdressing at jointing stage, reducing nitrogen application on thebasis of N4treatment decreased the biomass and yield of winter wheat and summer maize.Adding25%of nitrogen improved biomass of winter wheat and summer maize but did notsignificantly influent the yield. However, adding50%of nitrogen did not significantlyinfluent the biomass and yield, indicating the addition of nitrogen on the basis of N5wasinvalid input. Adding25%~50%of nitrogen on the basis of N2did not significantly promotethe biomass of winter wheat and summer maize when topdressing at jointing and anthesisstage.Under the same nitrogen application rate, topdressing at jointing and anthesis stage did notsignificantly improve the biomass of winter wheat but significantly enhanced wheat yield inN3and N4treatment and promote the improvement of biomass and yield of summer maizecompared to topdressing at jointing stage.6Effects of nitrogen management in wheat season on nitrogen utilization efficiency ofwinter wheat and summer maizeUnder the same topdressing stage, with the increasing nitrogen application in wheat season,nitrogen agronomic efficiency and nitrogen partial factor productivity in wheat significantlydecreased but those in maize continually improved. Nitrogen use efficiency of the whole yearrose firstly and then decreased continually, with the highest value in N4treatment. Comparedto topdressing at jointing stage, topdressing at jointing and anthesis stage in wheat seasonimproved nitrogen agronomic efficiency and nitrogen partial productivity of winter wheat andsummer maize and improved the utilization of residual nitrogen from wheat season in summermaize.It was concluded that nitrogen application rate at225kg·hm-2with topdressing at jointingand anthesis stage might be the optimal nitrogen management in wheat season under winterwheat and summer maize cropping system and the experimental condition, by integrating theresults in terms of grain yield, nitrogen agronomic efficiency, nitrogen partial productivity,and nitrogen use efficiency.更多还原