Influence Of Nitrogen And N-P-K Ratio On Changchun Dark Sun-cured Tabacco’s Carbon And Nitrogen Metabolism,yield And Quality

Aiming at the phenomenon that high N consumption without P and K fertilizer adoption leads to excessive plant growth, high nicotine amount, low potassium content, bad combustibility and weak style of the dark sun-cured tobacco in Changchun City, this reach studied the influence of N-P-K ratio on the dark sun-cured tobacco growth, C-N metabolism, yield and quality, helping to provide references for producing high-quality dark sun-cured tobacco with reasonable fertilization. The results are as follows:1. N rate and N-K-P ratio have a significant influence on the dark sun-cured tobacco’s agronomic character. Every index of the dark sun-cured tobacco rises when increasing N rate and promoting N-P-K ratio, and also shows remarkable differences with the different N rates. The tobacco plant grows well and owns balanced nutrition under T5 treatment of medium N, medium P and high K during the maturity.2. With the growth process moving forward, the accumulation of DM in every organ of dark sun-cured tobacco rises with an increasing N rate, and the accumulation amount in leaves is larger than the one in stem which is larger than the one in root. Accumulation amount of DM in treatments with different fertilizers is larger in various degrees than the one without fertilizers, but it’s significantly higher under the high N amount, which may cause leaf green and late-maturing.3. The ground part of nitrogen, phosphorus and potassium content of tobacco plant and accumulation are increased along with the advance of growth period. High nitrogen treatment can increase the absorption of nitrogen of tobacco plant. Under the same nitrogen level with the increase of dosage of phosphate phosphorus content and accumulation amount increase. Under the same nitrogen level with the increase of dosage of potassium fertilizer increased potassium content and accumulation. The ground part of tobacco plant sulfur, calcium, magnesium accumulation in the whole developing a trend of increase gradually. Appropriate increase potash use can reduce the sulfur content in tobacco leaves. High nitrogen treatment can promote the maturation of tobacco plant absorption of calcium. A little effects on the accumulation of the various treatments for magnesium4. N-P-K ratio of 1:1.5:3 under low N amount and N-P-K ratio of 1:1:3 under medium N amount promote carbon metabolism, and increase the content of total sugar,reducing sugar and starch in carbon metabolites. Increasing N fertilizer improves the activeness of key enzymes in Nitrogen metabolism of tobacco leaves in latter stage, which rises total N content and nicotine content in N metabolites, while increasing K ratio under high N amount suppresses N metabolism.The content of chlorophyll a, chlorophyll b and carotenoids rise with a increasing N rate, it has a change with mono-peak curve, and reaches the maximum on the 30 th day of leaves, but it degrades insufficiently during the leaves maturity.5. N rate and N-P-K ratio have a significant effect on dark sun-cured tobacco output and value which shows a tendency to increase when increasing N amount and obtaining reasonable P-K ratio, superior tobacco and medium tobacco account for a larger proportion under the medium N amount.6. Agronomic utilization gradually reduces with an increasing of fertilizer consumption. Adding P fertilizer promotes agronomic utilization under the same N amount. Tobacco plants absorb less from soil when adding more fertilizers,which affects plant’s absorption of soil nutrition.7. Adding N amount improves tobacco leaf length, width, leaf weight and quality weight, and suitable N rate reduces stem ratio of tobacco whose filling value is higher under the medium N amount.8. The content of total sugar, reducing sugar and starch of dark sun-cure tobacco reduces with increasing N consumption, the maximum value appears in the treatment where N-P-K ratio is 1:1:2 or1:1:3 under the low N amount. When adding N consumption, nicotine and total N content rises, reaching the appropriate value under the medium N amount. K content rises with an increasing of K fertilizer under the same N amount, reaching a higher value under the high and medium N amount; chlorine content in every treatment has no remarkable difference. The chemical composition is relatively coordinated when N rate is 67.5kg/hm2 and N-P-K ratio is 1:1:3.9. Different treatments have below effects on neutral aroma substances in sun-cured tobacco: the content of browning reaction compounds and neophytadiene in the upper tobacco leaves is higher under the high N amount, the content of phenylalanine degradation products, carotenoid degradation products and Cembratriendid alkyl degradation products in the upper leaves is higher under the low N amount. The content of phenylalanine degradation products, carotenoid degradation products in the middle leaves is higher under the medium N amount, while the content of ronwing reaction compounds and neophytadiene is higher under the low N content; the total content of neutral aroma component in upper leaves is higher under the high and medium N amount while the one of middle leaves is higher under the low N amount, which indicates that higher N rate increases the content of neutral aroma component in the upper leaves while less N rate improves the one in the middle leaves. The total content of alkaline aroma substances in the dark sun-cured tobacco is relatively lower. Under the medium P amount and high P amount, the content of alkaline aroma substances is higher with adding N fertilizer in high N treatment.10. Different N amounts play no distinct rules to effect TSNA content. Under the same N rate, TSNA amount tends to drop with an increasing of K consumption, reaching the bottom in T3 treatment of the whole.11. Among different parts of a plant, the dark sun-cured tobacco’s sensory quality of top leaves is better than the one of middle leaves, and it has distinctly difference but no certain rule among different treatments. T5 treatment shows the highest score from leaves of upper-middle part.The study indicates that N rate of 67.5kg/hm2 and N-P-K ratio of 1:1:3 is beneficial for the growth and development of dark sun-cured tobacco, and also for the formation of sun tobacco’s quality.