Effects of Water and Nitrogen Coupling on the Water and Nitrogen of Soil and Yield and Quality of Flue-cured Tobacco in Luzhou

Field experiments on the coupling effect of water and nitrogen on the tobacco cultivar Yunyan 97 with irrigation have been conducted in the year of 2010.The influence of coupling effect between water and nitrogen coupling on the growth and the dynamic changes of water and nitrogen in the field yield, quality of the tobacco were studied in this experiment. The object was to provide theoretical evidence for the tobacco production. The main results were as follows:1. The content of soil moisture increased as the soil layer depth during the rosette stage of tobacco, but the content of soil moisture was decrease from the depth of 40 to 60 cm during the vigorous growing stage, and further increased. The content of soil moisture in the depth of 0 to 80cm was increased significantly by use of irrigation and nitrogen fertilizer, except the depth of 60 to 80 cm during the vigorous growing stage. The soil moisture content of the treatment without nitrogen increased with the irrigation increased. Overall, the soil moisture content during the rosette stage was higher than vigorous growing stage.2. Soil available nitrogen content reduced with the depth increase during the rosette stage and vigorous growing stage, the soil available nitrogen content reduced significantly in the depth of 40 to 80 cm of the treatment of no irrigation and moderate irrigation. From the whole, the content of soil available nitrogen of rosette stage was lower than vigorous growing stage.3. Irrigation increased plant height, stem circumference and maximum leaf area of tobacco and was beneficial to tobacco morphogenesis. But stem circumference and maximum leaf area of tobacco decreased with the increase of water level and nitrogen rate within the range of nitrogen 0～150 kg/hm~2.4. The dry matter accumulation of tobacco reach the most amount when the water level of 300m~3/hm~2 and nitrogen rate of 105 kg/hm~2 were applied after transplanting 75 days.5. In different treatment combination, the nicotine amount increased which reached maximum after the transplanting 45～60 days and the total nitrogen amount decreased along with promoting growth period. The irrigation had significant impact on nicotine content, and the nitrogen rate had greater impact on the total nitrogen content at every growth period.6. Regardless of irrigation, the total nitrogen content of tobacco leaves increased with increasing nitrogen rate. The nicotine, total sugar and reducing sugar content of irrigation increased first and then decreased. The combination of the middle irrigation amount (300m~3/hm~2) and the nitrogen rate of 75 kg/hm~2～105 kg/hm~2 had appropriate content of chemical components and better quality.7. The content of Ca in flue-cured tobacco increased with increasing nitrogen rate. The content of P、K and Ca content would increase through irrigation, while the content of Mg, Fe and Mn would decrease with increasing water amount.8. The petroleum ether extract content in flue-cured tobacco leaves would increase under the combination of irrigation and the nitrogen amount of 105 kg/hm~2.9. Irrigation obviously improved the total amount of aroma. The total amount of aroma under no nitrogen and the nitrogen amount of 105 kg/hm~2 increased as the water amount increased, while the remaining nitrogen treatment increased first and then decreased with increasing water amount. In the treatment of no irrigation and high irrigation, the total amount of aroma under the nitrogen rate of 105 kg/hm~2 was highest, and that of no nitrogen was lowest.10. The output value, average price and the proportion of high grade leaves under the combination of water amount of 300m~3/hm~2 and nitrogen rate of 105 kg/hm~2 were higher than other combinations, which reached 21195.69yuan/hm~2,10.97yuan/kg and 36.67%. The field of flue-cured tobacco increased as the nitrogen rate and water amount increased.