【摘要】 在较低施氮量[180 kg(N).hm-2]下,以"郑单958"为材料,研究了氮肥不同基/追比(1∶2、1∶1和2∶1)对华北平原夏玉米氮素累积、转运与土壤无机氮动态及土壤氮素表观盈亏的影响。结果表明:施氮使夏玉米氮素累积量增大,并促进叶、茎鞘氮素向籽粒转运,但不能相应提高氮收获指数(NHI),且NHI随基施氮比重增大而降低;基施氮主要在拔节至大喇叭口期发挥作用,追施氮则主要在大喇叭口至吐丝期发挥作用,氮肥利用率随追氮比例增大而提高,N 1∶2较N 2∶1处理氮肥利用率提高2倍多;土壤无机氮含量因施氮而有较大幅度提高,拔节期后各土层无机氮含量一般以乳熟期为界前降后升,处理间略有差异,追肥越少此趋势越明显;不施氮处理各生育阶段土壤氮素均表现亏缺,吐丝后亏缺量占总亏缺量近80%,施氮使总亏缺量大大降低,N 1∶1处理氮亏缺量最小,N1∶2与N 2∶1处理相当,各施氮处理土壤氮素表观盈亏呈明显的阶段性,拔节至大喇叭口期出现大量盈余,从而使播种至吐丝期整体表现盈余,吐丝后两阶段均表现亏缺。更多还原

【Abstract】 Under low N application rate [180 kg(N)·hm-2],"Zhengdan958" was used to study the effect of different Ratios of Base N to Dress N(RBTD)—"1∶2,1∶1 and 2∶1" on N accumulation and translocation,and the dynamics of soil inorganic N and apparent soil N budget in summer maize.Results show N accumulation in N treatments increases and N translocation increases from leaves,stems and sheathes to grains.However,Nitrogen Harvest Index(NHI)does not increase proportionately and NHI decreases with increase in RBTD.Base N and dress N are important mainly in jointing to ♀floret and ♀floret to silking,respectively.Nitrogen use efficiency increases with increasing RBTD,and that of RBTD 1∶2 is more than 2 times of that of RBTD 2∶1.Soil Inorganic N Content(SINC)evidently increases after N application.From jointing to mature stage,SINC shows both decreasing and increasing trends with dough stage as the critical point.However,a little difference exists between treatments,and the less dress N the more evident is the trend.In N 0 treatment,Soil N Deficit(SND)appears for the entire duration and nears 80% SND after silking.SND amount obviously decreases after N application,and that of RBTD 1∶1 is smallest,while the other two are almost equal.Apparent soil N budget in N treatments shows evidence of staggering characteristics.Soil N Surplus(SNS)appears in seeding to silking stages because of mass SNS in jointing to ♀floret and SND appears at two stages after silking.更多还原