Correlation Analysis between Nicotine Content of Flue-cured Tobacco Leaves and Soil Nutrients

The relationship between soil nutrients and nicotine content of flue-cured tobacco leaves was analyzed by descriptive statistic analysis, stepwise regression analysis and canonical correlation analysis under the same cultivation conditions in 12 counties of 7 provinces. The results indicated that considerable differences of soil nutrient contents were found in different pilot counties. The variation extents of available P and total P were the biggest. The soil pH exhibited balanced distribution, while available K and total K showed the opposite. The variation of nicotine content was bigger in lower leaves than that in middle or upper leaves. There was significant correlation between nicotine content and soil nutrients. The correlation degree between nicotine content of different positioned flue-cured tobacco leaves and soil nutrient was apparently different. The dominant soil nutrient factors influencing the nicotine content of tobacco leaves were available N, pH, OM, available P and total P. The available N had the greatest effect on nicotine content, followed by soil pH. The available N, pH and OM had positive effects on nicotine content, while the available P and total P had negative correlations with nicotine. The principle measures to nutritional regulation of nicotine included the selection of weak acidic soil with moderate organic matter content, the control of nitrogen fertilizer rate and the increase of phosphate fertilizer rate.