Study On The Suitable Nitrogen Application Rate For Yunyan97in Mojiang, Yunnan

The flue-cured tobacco Yunyan97developed from the hybridization between Yunyan85and CV87in Tobacco Agricultural Research Institute of Yunnan Province and was approved by National Tobacco Variety Committee in March2008. The variety in Yunnan area have a high adaptability and better cultivation, baking characteristics and excellent economic traits, and the planting area expanded year by year.The purpose of this study was to explore the effect of different nitrogen rate (3、5、7、9、11kg/666.7m") on agronomic characters and quality evaluation of Yunyan97, and provide theoretical basis for rational fertilization in Mojiang tobacco area. In our experiment, in five different nitrogen rate treatment, the main agronomic traits in the growing stage,20days,40days,60days after transplanting, the day before topping, the day before roasting were studied, moreover, economic quality, appearance quality, chemical composition and coordination, sensory quality of tobacco after roasting were also studied. A comprehensive evaluation of the quality of tobacco was conducted according to the standard of the raw material quality on Jiangsu Tobacco cigarette brands. The results showed that:With the increasing of nitrogen rate, each growth period of Yunyan97before the vigorous growing stage tended to be earlier than expected, and these growth periods after the budding stage tended to be later than expected in this test. In addition, the growing stage in treatment E was delayed by11days than that in treatment A. There was a significant difference among different nitrogen rate treatments on agronomic traits from the40th day after transplanting. Plant height, stem girth, number of leaves and leaf area were enhanced with the increasing of nitrogen rate, in addition, tobacco yield after roasting also increased. The nicotine and total nitrogen content in the tobacco Yunyan97after roasting were influenced by nitrogen rate greatly, and the range of the nicotine content at the same position reached0.9%between different treatments. Furthermore, evaluating score of the nicotine content, total nitrogen content and the ratio of sugar to nicotine decreased most significantly with the increasing of nitrogen rate on middle and upper leaves. When the nitrogen rate reached a certain level (9kg/666.7m2), excessive nitrogen fertilization had a negative impact on economic quality, appearance quality, chemical composition and coordination, sensory quality of Yunyan97. This study suggested that the appropriate nitrogen rate of the flue-cured tobacco Yunyan97when planting in Mojiang tobacco area was at5-7kg/666.7m2, when the tobacco quality best meet the raw material quality requirements of the cigarette industry.