为了探索烤烟氮素积累与土壤有机质含量及施氮量的关系,以不同有机质含量的黄壤为试验地,研究了不同施氮条件下烟株的氮素积累及分配利用规律.结果表明:1)不施氮烟株的氮素积累量在生育期内持续增加,并随土壤有机质含量的增加而增加；相同施氮条件下,植烟在高有机质含量土壤上的氯素积累主要在烤烟移栽后77d内,低有机质含量土壤则在烟株整个生育期内持续增加,且增加施氮量其氯素积累的总量变化不明显.2)在相同施氮条件下,高有机质含量土壤上的烟株肥料氮和土壤氮积累均集中在77d内,而低有机质含量土壤上的烟株在77～119d仍有大量的肥料氮和土壤氮积累.3)烟株肥料氮积累总量占其氮素积累总量的33.59％～48.26％;土壤氮积累总量占烟株氮素积累总量的51.74％～66.41％,土壤氮是烤烟氮素营养的主要来源,并随着土壤有机质和施氮量的增加而下降,也是烤烟不同部位叶片中的氮素营养来源,并随着叶片部位的升高积累量增加.4)烤烟对氮肥的利用主要集中在旺长期(36～77d),在相同施氮条件下,随土壤有机质含量的增加而增加；在适宜施氮条件下,选择有机质含量较高的土壤植烟,对促进烟株前期生长和氮素积累有益,对促其早生快发和较早形成优势植株有利,而且通过加大施氮量提高烟株氮素积累的效果较微.因此,施氮量应以当地最佳用量为准,同时,为了提高烤烟的氮肥利用率和节约氮肥投入成本,可选择有机质含量较高的土壤种植烤烟.%To explore the relationship of nitrogen accumulation in flue-cured tobacco with organic matter content in soil and nitrogen application levels, a field experiment was conducted to explore the nitrogen accumulation, distribution and utilization low on yellow soil with different organic matter content. Results: 1) Without nitrogen applied, the nitrogen accumulation amount grew continuously in growth stage and kept increasing with the increase of organic matter in soil; Under the same nitrogen level, nitrogen accumulation of tobacco plants on soil with high organic matter content occurred mainly within 77 d after transplanting. While occurred in the whole growth stage on soil with low organic content. Meanwhile, the total nitrogen accumulation showed no significant change under high nitrogen levels. 2) Under the same nitrogen levels, the fertilizer N and soil N of tobacco plants with high organic matter content in soil were mainly absorbed during 77 d after transplanting. While with low organic matter content in soil, a large quantity of fertilizer N and soil N accumulation continued in 77 -119 d. 3) The total fertilizer N accumulation made up 33. 59%--48. 26% of the total nitrogen accumulation) the total soil N accumulation made up 51. 74%~66. 41% of the total nitrogen accumulation. The soil N was the main source of nitrogen nutrition for tobacco plant and it decreased with the increase of nitrogen levels and organic matter in soil. It was also the source of nitrogen nutrition for leaf blade in different part the tobacco plant and its nitrogen accumulation increased with the ascending of the leaf blade. 4) The utilization of nitrogen fertilizer for tobacco plant was mainly centered on the vigorous growing stage (36~ 77 d). Under the same nitrogen level, the nitrogen accumulation increased with the increase of organic matter content in soil. Under the optimum nitrogen condition, planting the tobacco in high organic soil was helpful to its early growth and the nitrogen accumulation. It was also beneficial to the development of the plant and the forming of the dominant plant as early as possible. The result was not good through increasing the nitrogen levels to increasing the nitrogen accumulation of the tobacco plant. Therefore, nitrogen level should be subject to local optimum dosage. At the same time, to increase the utilization ratio of nitrogen fertilizer and save nitrogen fertilizer input cost, soil with high organic matter content could be chosen to plant the flue-cured tobacco.
展开▼
