Effects Of Fertilization And Topping On The Content Of Important Nitric Compounds In Flue-Cured Tobacco

Experiment in field and pots were carried out during 2002-2003 in tobacco company of QueShan Henna provice and the farm of Henna agricultural university. Mainly study the effect of some cultural measures on the content of important nitric compounds in flue-cured tobacco leaf. These ways are the amount of nitrogen fertilizer, the rate of organic fertilizer and the periods of topping.The conclusions are as follows:1. The impact of nitrogen fertilizer and topping on the content of nicotine and nornicotine in flue-cured tobacco leafThe content of nicotine and nornicotine in flue-cured tobacco leaf has direct relation with the nitrogen fertilizer level.the higher application of nitrogen fertilizer amount,the higher content of nicotine and nornicotine in leaf.In cutters, the content of nicotine is on the rise in the latter stage of maturity, on the other side, according to the content of nornicotine, there is downward trend at the same period, which is favorable for reducing the negative effect of nornicotine. In the situation of applying same amount of nitrogen fertilizer, the higher proportion of organic fertilizer can decrease the content of both nicotine and nornicotine. That is to say organic fertilizer can reduce the content of alkaloids in some degree,and it has more obvious reducing function on nornicotine than on nicotine.In the different periods of topping, cutters and lugs appear the trend that the earlier of topping time the higher content of nicotine and nornicotine.Regarding to the upper leaf, which show the law that the latter of topping time the higher content of alkaloids;So it is inadvisable that postponing the topping time in order to reduce the amount of alkaloids. All in all, topping at the right time (neither too early no too late) is an effective way to guarantee tobacco leaf with proper alkaloids.2. The impact of nitrogen fertilizer and topping on the content of free nicotine in flue-cured tobacco leafWith the amount nitrogen fertilizer rising,the content of free nicotine and the proportion of free nicotine accounting total nicotine are increasing in cutters and lugs; though the free nicotine content in upper leaf also has a rise, the proportion of free nicotine accounting total nicotine don't change much.In the situation of applying same amount of nitrogen fertilizer, with the higher proportion of inorganic fertilizer, the content of free nicotine and the proportion of free nicotine accounting total nicotine rising in upper leaf; But according to cutters and lugs the content of free nicotine doesn't not improved thereupon; when all the fertilizer are organic both ofcutters and lugs with highest content and proportion of free nicotine. Even applying too much organic nitrogen fertilizer can decrease the content of free nicotine in upper leaves,but it also increase the content of it in cutters and lugs and make them more irritating.According to the different periods of topping, for the cutters and lugs, the content and the proportion of free nicotine are highest when topping too late and lowest when topping at the proper time. It shows that it is negative for the tobacco leaf quality if we don't topping it at the proper time.But about the upper leaf, the content and the proportion of free nicotine are highest when topping at the proper time and lowest when topping late.lt is different from the cutters and lugs.3> The impact of nitrogen fertilizer and topping on the content of nitrate, nitrite and activity of nitrate reductases in flue-cured tobacco leafBeing applied more nitrogen fertilizer,there are higher content of nitrate and nitrite in all the periods of the tobacco life,and the leaf contain low amount of nitrate and nitrite with low nitrogen fertilizer application.Which may tells us that higher nitrogen fertilizer application can increase the content of nitrate and nitrite in flue-cured tobacco leaf.Furthermore,from the topping day to 2 weeks later of it,the content of nitrate is decreasing and the content of nitrite is increasing, which show that this is a...