Effects of Nitrogen Rates on Growth, Development, Yield and Quality of Dark Sun-cured Tobacco in West Hunan

The effects of nitrogen rates on the growth, development, nutrient contents, economic characteristics and quality of dark sun-cured tobacco were studied by field experiments.The results showed that in the range of 0-150 kg/ha, the plant height, leaf area, contents of total N, P and K in tobacco plant, yield, value and proportion of high and middle grades cured leaves, contents of total nitrogen, nicotine and protein in cured leaves increased with the increase of N application rates, while the content of sugar decreased.When N rate was 150 kg/ha, the cured leaves had moderate nicotine content, richer aroma and less irritation.