Effect Of The Nitrogen Fertilizer Application Rate On Growth And Development, Photosynthetic Characteristics And Qulity Of Cigar Wrapper Tobacco

In 2004-2005, through pot experiment on the farm of Henan Agricultural University and field trial in Baisha County, Hainan Province, growth and development characters, photosynthetic characteristics and quality of cigar-wrapper tobacco under different nitrogen fertilizer levels were studied. The results were as follows:1. Effects of different nitrogen fertilizer levels on the growth and development of cigar-wrapper tobaccoNitrogen fertilizer could enhance the plant height, increase the stem girth, enlarge the maximal leaf area and so that increase the leaf area per plant and coefficient of leaf area. However, these increases didn't show the consistent trend with the increase of nitrogen fertilizer. The result was N15(10g per pot)>N10(6.7g per pot)>N20(13g per pot) and it indicated that only proper nitrogen fertilizer level could promote the growth of plant and the development of leaf.Accumulation of dry weight per plant of cigar-wrapper tobacco showed "S" type growth curve under different nitrogen fertilizer levels. The accumulation of dry weight per plant all increased obviously at different growth and development stages.With the increase of nitrogen fertilizer, the content of N, P and K all increased. But, there was not to say that the more we use the nitrogen fertilizer, the more the increase we get. The quantity of nitrogen fertilizer should have a proper scope. If the amount exceeded 225 kg per hm~2, the effects would decrease.Based on the changes of accumulation of the dry weight per plant, the increase of quantity of nitrogen fertilizer could increase the leaf photosynthetic area, promote the plant's absorption of P and K and then could produce higher biomass to establish the quality basis of tobacco leaf.The content of nicotine, total sugar, reducing sugar decreased with the increase of the nitrogen fertilizer amount. So did the content of starch at early stage. These results indicated that the increase of nitrogen fertilizer amount went against the accumulation of carbonous compounds because more products of photosynthesis were used to accelerate the growth of the plant.