| Field experiments were conducted during 2007-2008 to study the effects of different transplanting periods and methods of fertilization on agronomic characteristic, accumulation of the dry matter, macroelement and microelement characteristic, carbon and nitrogen metabolite of cutters and upper-leaf, yield and quality of the aromatic tobacco of Yunnan. The results were as follows.1 Effect of different transplanting periods on growth and quality of aromatic tobacco1.1 With the transplanting periods of tobacco postponing, the indicators of agronomic characteristrics first increased and then reduced. The tobacco was transplanted in November 18,the height, stem girth and available leaves of the plant were significantly better than the others. looking from the whole growth period, the tobacco was transplanted in November 18,the number of leaves and the size of Leaves are consistent with the best produce requirements of aromatic tobacco. Its lay the foundation for the best yield.1.2 During the whole growing period, the dry matter of aromatic tobacco presented slow-fast-slow increasing trend. It was similar to change of dry matter accumulation of flue-cured tobacco, but the accumulative velocity of the dry matter was different in different period. With the transplanting periods of tobacco postponed, the dry matter of aromatic tobacco presented first increasing and then reducing. When plant was transplanted in November 18,the dry matter accumulation was the largest.1.3 During the whole growing period of the cutters and upper-leaves. The content of chlorophyll presented declining trend. And with the transplanting periods of tobacco postponed, the content of chlorophyll presented increasing trend.1.4 During the whole growing period, the absorption of various macroelement in tobacco increased. With the transplanting periods oftobacco postponed, its content performed: K>Ca>Mg>P.Before the 60d 0f transplanting, The Ca, K, Mg, P accumulation of each creatment were less. With the transplanting periods of tobacco postponed, the absorption of various microelement in tobacco decreased. During the whole growing period of tobacco in creatment two, the absorption of B、Cu、Fe remained relatively high growth rate after the 60d of transplantation. The peak of Mg, Zn accumulation appeared in the 75d-105d. During the whole growing period of tobacco in creatment three , the peak of B、Cu、Mg、Zn accumulation appeared in the 60d-105d. After the 105d, the accumulation of B、Cu、Mg、Zn Showed a decreasing trend. After the 60d ,the accumulation of Fe maintained a relatively high growth rate. During the whole growing period of tobacco in creatment four.the peak of B、Cu、Fe、Mg、Zn accumulation appears in the 60d-105d.1.5 With the transplanting periods of tobacco postponed, during the whole growing period of the cutters, Inv activity of the leaves in each creatment declined slowly.The activity of SS、SPS increased before reduced, and so did the GS activity of four creatmentments.But the GS activity of the fifth creatment always maintained decreasing trend. It indicated that the transplanting period was too late, the conduct of nitrogen metabolism in leaves would be affected seriously.During the whole growing period of the upper-leaves, the peak of the Inv activity in leaves appeared in the 20d of leaves’age in the each creatmentment. The Inv activity decreased fastly after 20d.The changes of the SS、SPS activity varied greatly. The changes of GS activity was similar to the cutters.1.6 With the transplanting periods of tobacco postponed, the chemical components of cured leaves varied greatly in each creatment. The chemical components of the fifth creatment were very uncoordinated. Comparied with the each treatment, the result was that: TS、RS and content of K were less than the other three creatments. In accordance with the request to reducing sugar and increasing the content of nicotine of the upper leaves of aromatic tobacco in Yunnan, we should appropriately increased the amount of nitrogen with the basis of three creatment. With the transplanting periods of tobacco postponed, the yield and quality first increased and then reduced. When tobacco was transplanted in the second half of November, the yield and quality were the highest.2 Effect of different amount of nitrogen and method of nitrogen on growth and quality of aromatic tobacco2.1. The amount of nitrogen impacted significantly plant height, available leaves and the largest leaves of the aromatic tobacco. The early growth of tobacco plant, the height, stem girth and available leaves of the plant increased with the increase of the amount of nitrogen. After 120d, inside the scale of 60 kg/hm2, with the increase of the amount of nitrogen, agronomic characteristic of plant increased; Outside the scale of 4 kg/hm2, it reduced slightly.2.2 During the whole growing period of tobacco, increasing the amount of nitrogen and The N dressing rates, the accumulative velocity and accumulation of the dry matter increased together. But when the amount of nitrogen exceeded 60 kg/hm2, the accumulation of the dry matter redused slightly.2.3 With the increase of the amount of nitrogen and the nitrogen dressing rates frequency, the SS、SPS activity of cutters in each creatment increased with the increase of leaves’age .And there were two peaks at the 20d and 40d. With the increasing of leaves’age, GS activity first increased and then reduced.2.4 During the growing and maturing of the cutters, the content of total nitrogen presented decreasing trend.The content of total nitrogen in creatment 1 and creatment 3 presented decreasing trend slowly. Before the 30d, the content of total nitrogen in creatment 2 did not change significantly. After the 30d, it presented decreasing trend slowly.The content of total carbon presented increasing trend. Between the 20d and 40d, the content of total carbon in cutters of creatment 2 was greater than the other creatments.When the 50d,the content of total carbon of leaves in each creatment was changed a little. With the increased of the nitrogen dressing rates frequency, the content of total nitrogen presented decreased trend too. In earlier stage of leaves’development, the content of total nitrogen of the cutters in three creatments was more significant. After 30d, the content of total nitrogen of the cutters in three creatments presented different degree of decreasing trend. When the 50d, the content of total nitrogen of leaves in three creatments changed a little, the content of total carbon in each creatment presented a increasing trend, and always expressed as:creatment B> creatment A> creatment C.2.5 In a certain range,with the increased of the amount of nitrogen,the yield and quality of cured leaves increased. But when the amount of nitrogen exceeded 60 kg/hm~2, the yield and quality of cured leaves decreased slightly. The content of total nitrogen and nicotine presented increasing before reducing.Inside the scale of 60 kg/hm~2 with the amount of nitrogen increased, the content of total nitrogen and nicotine of cured cutters and upper-leaves increased. Beyond the 60 kg/hm~2, the content of total nitrogen and nicotine of cured cutters and upper-leaves decreased. The K of upper-leaves increased with the increased of the amount of nitrogen.So did not the K of cured cutters and lower-leaves. In the same nitrogen level, with the rising of N dressing rates, the yield and quality of cured cutters and upper-leaves could be improved. The content of total nitrogen nicotine and K increased, and those chang were more significant. The content of total suger and reducing suger of cured cutters and upper-leaves changed little. but comparing with the lower leaves, there were significant differences. The content of Cl decreased with the increased of dressing frequency, Generally speaking, the N application was 60 kg/hm~2, and 50% was base nitrogen fertilizer, 50% was additional, the cured leaves showed a superior appearance. The chemical components were harmonious, residual taste was comfortable, and the quality achieved excellent. |
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