Abstract:

To further explore the effects of different forms of nitrogen fertilizer on the growth, yield and quality of flue-cured tobacco, the effects of different ratios of ammonium nitrogen and nitrate nitrogen on the growth period, agronomic traits, chemical composition and sensory quality of flue-cured tobacco were studied. The results showed that there was no significant difference in the growth period of tobacco plants among different nitrogen fertilizer forms. The agronomic traits of different nitrogen fertilizer treatments showed some differences, but there was no obvious regularity. At the flat-top stage, with the increase of ammonium nitrogen ratio and the decrease of nitrate nitrogen ratio, the length and width of lower tobacco leaves and the length of middle tobacco leaves showed a gradually increasing trend, but the difference was not significant. When the ammonium nitrogen ratio was more than 60%, the width of middle tobacco leaves decreased. When the proportion of ammonium nitrogen was the highest, the length of upper leaves was significantly higher than that of other treatments, but the proportion of different forms of nitrogen fertilizer had no significant effect on the width of upper leaves. With the increase of the proportion of ammonium nitrogen fertilizer application, the yield, output value and the proportion of superior tobacco showed a gradually increasing trend. When the ratio of treatment with ammonium nitrogen to nitrate nitrogen was 7:3, the highest yield, output value, proportion of superior tobacco and average price were obtained, but the increase was not significant. When the ratio of treatment of ammonium nitrogen to nitrate nitrogen was ≤5:5, the chemical composition of flue-cured tobacco leaves was more suitable, and the proportion was more coordinated. With the increase of ammonium nitrogen ratio and the decrease of nitrate nitrogen ratio, the sensory quality of flue-cured tobacco leaves showed a trend of increasing first and then decreasing. The sensory quality evaluation score was the highest when the ratio of ammonium nitrogen to nitrate nitrogen was 5:5. When the ratio of ammonium nitrogen to nitrate nitrogen was greater than 5:5, the sensory quality decreased rapidly. The ratio of ammonium nitrogen to nitrate nitrogen in Ankang tobacco area is 5:5, which takes into account both quality and efficiency.

Key words: nitrogen fertilizer form, fertilizer ratio, flue-cured tobacco, yield and quality