Influence Of Nitrogen And Potassium Absorb And Accumulated Characteristics And Yield And Quality Of Flue-cured Tobacco On Nitrogen Application Regime And Potassium Nutrition Regulation

As the most significant nutrient for plant, nitrogen has a huge effect on yield and quality of flue-cured tobacco. The reasonable nitrogen application rate and period are conducive to promoting the growth of flue-cured tobacco and coordinating its chemical quality to increase the yield and fertilizer use efficiency. Since potassium is the must-have nutrient for the growth of flue-cured tobacco, potassium content of flue-cured tobacco is a highly important index that measures the quality of flue-cured tobaccos. In the tobacco-growing regions in the South of Sichuan, nitrogen use efficiency and tobacco’s potassium content are low, which has severely impacted the quality of flue-cured tobacco there, Weaken the region sustainable development of flue-cured tobacco. In this research, micro-plot experiment is used to research the absorption, accumulation and distribution of nitrogen and potassium in tobacco, and explore nitrogen decrement and synergism technique as well as potassium control technique for the tobacco-growing regions in the South of Sichuan. In this way, clear the effect of nitrogen and potassium absorb and accumulated characteristics of Flue-cured tobacco on nitrogen fertilizer reduction and potassium nutrition regulation. Below are the major research results:(1) The micro area experimental results show that, the nitrogen absorption peak of flue-tobacco appears in 40～50 day after transplanting, taking up 47.04%～54.58% of total nitrogen accumulation amount in the whole growth period. Among them, nitrogen fertilizer reduction and moved forward and no nitrogen treatment uptake nitrogen peak in 40 day after transplanting, While nitrogen fertilizer reduction and moved backwards and conventional fertilization, uptake nitrogen peak in 50 day after transplanting. The distribution proportions of nitrogen in different organs are as follows:tobacco leaf> tobacco stem> tobacco root. In maturation period, the nitrogen contents in different organs of tobacco plant can be sequenced like this:upper leaves> middle leaves> lower leaves. the nitrogen accumulation amounts in different parts can be sequenced like this:middle leaves>lower leaves>upper leaves. The dry matter accumulation peak of flue-tobacco lies between 50～70 day after transplanting. With the development of growth period, dry matter accumulation in tobacco leaves gradually reduced, root and stem are gradually increasing. nitrogen application rate of 90 kg/hm2 and moved forward with promoting tobacco nitrogen absorption peak before on the absorption of nitrogen accumulation, and nitrogen application rate of 90 kg/hm2 and back treatment, promote the growth of flue-cured tobacco in the late of the absorption of nitrogen, but in the late absorb excessive nitrogen is likely to lower the quality of tobacco leaves.Single from fertilizer use rate point of view, the Lu-zhou tobacco growing areas of routine application of pure nitrogen 120 kg/hm2 down to 45 kg/hm2and shift fertilizer utilization rate of the highest nitrogen utilization rate compared with the conventional fertilization significantly increased the 33.24%. Pure nitrogen application amount to 45 kg/hm2 and although obtained higher fertilizer use efficiency, but also reflects the tobacco began to lack of fertilizer, and the amount of pure nitrogen reduced to 90 kg/hm2 and forward still has better effect and under field conditions, it is recommended the Lu-zhou tobacco growing areas of pure nitrogen content has been reduced to 90 kg/hm2 combined with basal fertilizer used, topdressing nitrogen compared to conventional nitrogen topdressing forward 10% as well.(2) The micro area experimental results show that, the potassium accumulation peak of flue-cured tobacco appears 45-65 day after transplantation, accounting for 60%～70% of total potassium accumulation amount in the whole growth period. As for flue-cured tobacco, tobacco leaf contains most potassium, then followed by stem and finally by root. The distribution of potassium in tobacco leaf decreased after the potassium of the period of the following potassium. The potassium accumulation amounts can be sequenced like this:topdressing 70 day after transplantation> topdressing 50 day after transplantation and topdressing 90 day after transplantation. The topdressing with 20% of potassium 70 day after transplantation is superior to topdressing with 40% of potassium 70 day after transplantation.From the fertilizer use efficiency point of view, after transplanting 70 day or 90 day after potassium can reduce flue-tobacco at after topping in a potassium ion efflux rate and increase tobacco plant in later stage of potassium absorption and accumulation, significantly increased the potassium utilization rate, reduced potassium dry matter production efficiency, the potassium use efficiency compared with conventional improves the 16.7%～35.10%, especially in 30 day after transplanting after application of 40%, transplanting after 70 days of topdressing 20% treatment was the highest.(3) Plot experiment results show that the roast tobacco leaf total nitrogen and nicotine content presented the trend of upper leaf> middle leaf> lower leaf, total nitrogen ratio nicotine, lower upper leaves; Total sugar and reducing sugar content are in high quality or suitable scope, total sugar ratio nicotine higher than medium and lower lobe; Smoke potassium content in both in appropriate range, the total Cl content is generally low, potassium ratio total Cl content the overall coordination. Nitrogen reducing and reach 10% and potash moved to 70 day topdressing 20% after transplanting with processing can be coordinated index of flue-cured tobacco chemical composition, improving smoke reduced nicotine, potassium and total nitrogen and total C1 content in tobacco leaves, make the alkali ratio, sugar alkali ratio of nitrogen and potassium total Cl than indexes in suitable range, such as maximum to meet the flue-cured tobacco chemical composition within internal coordination. With the conventional fertilizer treatments compared, upper,middle and lower leaves potassium content were increased by 13.33%,16.74% and 37.5%, yield and output value were increased 327.15 kg/hm2 and 4537.2 yuan/hm2, the proportion of superior tobacco significantly increased the nearly 20%.Therefore in Lu-zhou tobacco growing area the best nitrogen and potassium application types is the habit of nitrogen from 120 kg/hm2 dropped to 90 kg/hm2 and moved to 10% combined with potassium fertilizer after transplanting moved to 70 day topdressing 20%.