水肥一体化条件下烤烟氮素营养高效利用研究

Study on effective utilization of nitrogen nutrition in flue-cured tobacco production under integration of water and fertilizer

【目的】为探究水肥一体化技术对烤烟氮素营养利用效率的影响。【方法】试验设置了空白对照(CK)、常规栽培(FP)和水肥一体化(DF)3个处理,通过2年的田间试验和1年的盆栽实验,检测了3个处理不同时期烟株的干物质积累量和氮素吸收量,对比了3个处理不同生育时期烟株根系生长发育情况,并测定了常规栽培(FP)和水肥一体化(DF)处理烟叶硝酸还原酶(NR)和谷氨酰胺合成酶(GS)的活性和烤烟氮代谢相关的NITR和GS基因的表达量。【结果】(1)DF处理NR活性在移栽20 d和40 d均明显高于FP处理,分别是FP处理的1.26倍和1.31倍,NITR基因的相对表达量也均高于FP处理,在移栽80 d后,DF处理NR活性大幅下降60.81%,而FP处理下降较缓慢;(2)DF处理较FP处理能显著提高烟株根系活力和根体积,促进烟株根系生长发育和形态建成,使烟株氮肥表观利用率提高了93.21%,氮肥偏生产力提高了15.24%,土壤氮素依存率降低了15.01%;(3)DF处理和FP处理烟株干物质和氮素积累变化规律趋势相同,但DF处理的干物质和氮素积累量以及积累速率均较FP处理有明显提升,且DF处理干物质积累和氮素吸收高峰提前,烟株生育后期氮素调亏,成熟落黄较好,烤后烟叶品质较高。【结论】采用水肥一体化技术可以有效调控烟株对氮素的吸收,提高氮素利用率,对促进烟株干物质积累和产质量的提高有积极的影响。

【Objectives】Experiment was conducted to investigate high efficiency utilization of nitrogen nutrition under integrated water and fertilizer condition in flue-cured tobacco.【Methods】Comparison was made among control(CK),farmer's practice(FP)and drip fertilization treatment(DF)by monitoring dry matter accumulation and nitrogen uptake at different stages,comparing growth and development of root system at different stages,measuring activities of NR and GS in leaves of FP and DF treatments,and establishing relative expressions of GS and NITR.【Results】Results showed that:(1)NR activity of DF treatment was significantly higher than that of FP treatment on 20d and 40d after planting,1.26 and 1.31 times higher than FP treatment.Relative gene expression of NITR was also higher than FP treatment.The NR activity of DF treatment fell 60.81%80d after transplanting,while declined slowly in FP treatment;(2)DF treatment significantly improved root vigor and root volume,and promoted root growth and morphogenesis.N agronomic efficiency was increased by 93.21%and N partial productivity increased by 15.24%,while soil nitrogen dependence rate decreased by 15.01%;(3)Change of dry matter accumulation and N accumulation of DF and FP treatments were similar.Compared with FP treatment,both accumulation and its rate of dry matter and N in DF treatment were significantly improved.The peak of dry matter accumulation and nitrogen uptake both appeared earlier.With soil nitrogen reduction at late growth stage enabled tobacco leaves mature better and hence quality higher.【Conclusion】The regulation of dry matter and nitrogen accumulation by drip fertilization can have a positive effect on the improvement of N use efficiency,and consequently leaf yield and quality.