摘要：

为探讨优化基肥追肥比例结合氮肥用量对烤烟氮代谢和氮素吸收利用的影响,以烤烟品种粤烟97为试验材料,设置常规基追比6∶4+常规氮肥用量(CK)、基追比4∶6+常规氮肥用量(T1)、基追比4∶6+氮肥减量10%(T2)、基追比4∶6+氮肥减量20%(T3)、基追比4∶6+氮肥减量30%(T4)等5个处理,分析不同基追比结合氮肥用量对烤烟氮代谢、光合特性、干物质积累与氮素吸收、氮肥利用率及氮素平衡的影响。结果表明:基追比优化为4∶6后,谷氨酸脱氢酶(GDH)、谷草转氨酶(AST)、Fd-谷氨酸合成酶(Fd-GOGAT)等氮代谢关键酶活性均高于传统基追比6∶4的处理,结合减氮处理的氮代谢酶活性有所降低,其中减氮10%的T2处理与CK差异不大,但减氮20%~30%的T3、T4处理降低幅度较大,与CK差异显著。基追比优化为4∶6后,烤烟的光合速率、SPAD、干物质和氮素积累都明显增加,尤其是在大田生长后期处理间差异显著。基追比优化为4∶6后,烤烟的氮肥吸收利用效率大幅提高,氮肥农学效率、氮肥偏生产力、氮素当季回收率和氮肥经济利用效率分别比CK增加20.68%,6.89%,4.06,3.78百分点,结合氮肥减量各处理的土壤氮素平衡率比CK分别下降17.04~33.36百分点。综上所述,在南方烟区,将基追肥比例从6∶4优化为4∶6,可以促进烤烟大田中后期氮代谢,改善光合特性,增加物质积累和氮素吸收,提高氮肥利用率,结合肥料减量10%还可减少肥料投入,降低土壤氮素盈余,防范环境风险。

关键词: 烤烟, 基追比, 氮肥减量, 氮代谢, 氮肥利用率, 氮素平衡

Abstract:

To investigate the effects of optimizing basal-to-topdressing ratios combined with nitrogen application rates on nitrogen metabolism and nitrogen uptake/utilization in flue-cured tobacco,a field experiment was conducted using the cultivar Yueyan 97.Five treatments were designed:conventional basal-to-topdressing ratio (6∶4)+conventional nitrogen rate (CK),basal-to-topdressing ratio (4∶6)+conventional nitrogen rate (T1),basal-to-topdressing ratio (4∶6)+10% nitrogen reduction (T2),basal-to-topdressing ratio (4∶6)+20% nitrogen reduction (T3),and basal-to-topdressing ratio (4∶6)+30% nitrogen reduction (T4).It analyzed the impacts of these treatments on nitrogen metabolism,photosynthetic characteristics,dry matter accumulation,nitrogen uptake,nitrogen use efficiency,and nitrogen balance.The results showed that after optimizing the basal-to-topdressing ratio to 4∶6,the activities of key nitrogen metabolism enzymes,including glutamate dehydrogenase (GDH),aspartate transaminase (AST),and ferredoxin-glutamate synthase (Fd-GOGAT),were all higher than those under the traditional basal-to-topdressing ratio of 6∶4.When combined with nitrogen reduction treatments,the activities of nitrogen metabolism enzymes decreased.Specifically,T2 (10% nitrogen reduction) showed no significant difference from CK,while T3 and T4 (20%—30% nitrogen reduction) exhibited marked declines in enzyme activity.Optimizing the basal-to-topdressing ratio to 4∶6 also improved photosynthetic rate,SPAD values,dry matter accumulation,and nitrogen accumulation,with significant differences observed during the late growth stages.Furthermore,the optimizing 4∶6 ratio significantly enhanced nitrogen use efficiency.Compared to CK,nitrogen agronomic efficiency,partial factor productivity,recovery efficiency,and economic utilization efficiency increased by 20.68%,6.89%,4.06 percentage points,and 3.78 percentage points,respectively.Nitrogen reduction treatments reduced soil nitrogen surplus by 17.04—33.36 percentage points compared to CK.In conclusion,optimizing the basal-to-topdressing ratio from 6∶4 to 4∶6 in southern tobacco-growing regions enhances nitrogen metabolism during mid-to-late growth stages,improved photosynthetic performance,promotes dry matter and nitrogen accumulation,and increased nitrogen use efficiency.Coupled with 10% reduction in fertilizer can also reduce fertilizer input,mitigetes soil nitrogen surplus,and prevent environmental risks.

Key words: Flue-cured tobacco, Basal-to-topdressing ratio, Nitrogen reduction, Nitrogen metabolism, Nitrogen use efficiency, Nitrogen balance

中图分类号: 

• S572

• S143.1氮肥