Characteristic and Relationship of Magnesium Content in Flue-cured Tobacco Leaves and Exchangeable Magnesium Content in Soil in Hunan Tobacco-growing Areas

Characteristic and relationship of Mg content in flue-cured tobacco leaves and exchangeable Mg content in soils in Hunan tobacco-growing areas were studied by field and laboratory experiments. Results indicated that: The average Mg content in flue-cured tobacco leaves in Hunan was 0.378%, Mg deficiency in tobacco leaves was reached to 66.3% , and the Mg content decreased from north to south in Hunan; The average exchangeable Mg content in soils was 1.317cmol/kg, and 40% of the total area had low Mg content; The deficiency in soils and flue-cured tobacco leaves in tobacco-rice cropping system was severer than in single cropping system in dry land; The high significant positive correlation between Mg content in tobacco leaves and exchangeable Mg content in soils was observed. Severity and proportion of Mg deficiency in tobacco leaves was higher than those in soils.