Distribution and relationship of the zinc content in flue-cured tobacco leaf and available zinc content of soil in tobacco-growing areas in Hunan

Distribution of the zinc content in flue-cured tobacco leaf and available zinc content in soil and their relationship in Hunan tobacco-growing areas were studied by investigation and laboratory analysis. The results indicated that, (1) The zinc content in flue-cured tobacco leaf was suitable in total in Hunan tobacco-growing areas, which ranged from 10.50 to 100.50 mg.kg-1 with the mean of (36.30±14.05) mg·kg-1; the zinc content in 92.58% tobacco samples of the total was located in the range of 20.00~80.00 mg·kg-1; the order of the zinc content in flue-cured tobacco leaf among different grades was B2FC3FX2F. (2) Available zinc content in soil was medium in Hunan tobacco-growing areas, which ranged from 0.13 to 62.59 mg·kg-1 with the mean of (2.27±3.74) mg·kg-1 and variation coefficient of 155.09%. About 22.41% samples of total were lack of zinc (≤1.00 mg·kg-1), and samples of the zinc content in soil exceeding 4.0 mg·kg-1 accounted for 7.36%, and samples which satisfied with the growth of high quality tobacco accounted for 70.23%. The order of available zinc content in soil for different types was duck feces mud yellow mud field yellow ash soil yellow soil. (3) The zinc content in flue-cured tobacco leaf had high significant positive correlation at the 0.01 level with available zinc content in soil with correlation coefficient of 0.312, and also had significant positive correlation at the 0.05 level with available Cu, available Fe and available S in soil, but had negative correlation at the 0.05 level with pH value, available K and water soluble Cl in soil. (4) After grouping soil available zinc content and with the increasing of soil available zinc content, the zinc content of different grades in flue-cured tobacco leaf showed the trend of increasing firstly and decreasing later. Significant differences at the 0.05 level among groups were found for the zinc content of different grades in flue-cured tobacco leaf.