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

Distribution and relationship of manganese content in flue-cured tobacco leaf and available manganese content in soil in Hunan tobacco-growing areas were studied in field and laboratory experiments.Results indicated that:(1) The manganese content in flue-cured tobacco leaf was high in total in Hunan tobacco-growing areas,ranging from 15.00 to 740.80 mg·kg-1 with a mean of(146.66±134.03) mg·kg-1;the manganese content of 95.72% tobacco samples was in the range of 22.96～550.03 mg·kg-1;the manganese content of 42.41% tobacco samples was in line with the standard of high quality tobacco in Brazil(58.16～156.00 mg·kg-1);the order of the manganese content in flue-cured tobacco leaf among different grades was X2FB2FC3F.(2) Available manganese content in soil was high in Hunan tobacco-growing areas,ranging from 1.30 to 174.30 mg.kg-1 with a mean of(27.83±22.39) mg·kg-1;17.36% samples were lack of manganese(≤10.0mg·kg-1),while 20.19% samples had exceeding manganese(40.0 mg·kg-1).Samples satisfying the growth of high quality tobacco accounted for 62.45%.The order of available manganese content in soil of different types was yellow soil yellow ash soil yellow mud field red yellow mud duck feces mud sand mud field blue mud field.(3) The manganese content in flue-cured tobacco leaf had significant positive correlation at the 0.01 level with available manganese content in soil with correlation coefficient of 0.481.Based on correlation analysis,regression equation,y^=58.45+3.80x,was built between soil available manganese and flue-cured tobacco leaf manganese content in 257 samples.(4) After grouping soil available manganese content and with the increasing of soil available manganese content,the manganese content of different grades in flue-cured tobacco leaf increased,and significant differences at the 0.01 level among groups were found for the manganese content of different grades in flue-cured tobacco leaf.