Effects of Sulfur and Phosphorus Interaction on Selenium Enrichment in Flue-cured Tobacco

【Objective】The research was conducted to identify the effects of different application amounts of sulphur and phosphorus on the change of selenium content in flue-cured tobacco leaves.【Method】Taking a tobacco(Nicotiana tabacum L.) cultivar‘Yunyuan 205’as tested material, binary regression saturated D-optimal design experiment was conducted to study the selenium content in flue-cured tobacco leaves and the under-ground part, pH values and the aboveground biomass. 【Result】At the vigorous growth period, the application of KH2PO4 (4.33 g/kg) and （NH4）2SO4 (1.45 g/kg) had synergistic effect on the selenium absorption of flue-cured tobacco. While the sulphur and phosphorus nutrition in other treatments had antagonistic effect on selenium absorption. At the mature period, the application KH2PO4 (8.65 g/kg) and （NH4）2SO4 (5.81 g/kg) had synergistic effect on the selenium absorption of flue-cured tobacco. With the application amount of 15.39, 6.8, 10.73, 7.69 g/kg KH2PO4 and 0, 3.62, 8.33, 4.17 g/kg （NH4）2SO4, the sulphur and phosphorus nutrition had synergistic effect on the selenium absorption of flue-cured tobacco. There was no significant difference in selenium content in the underground part of flue-cured tobacco in two periods. For the above-ground part, the selenium content in flue-cured tabacco leaves in mature period was higher than that in vigorous growth period.Moreover, compared with single application of sulphur, single application of phosphorus fertilizer had higher selenium enrichment in flue-cured tobacco.【Conclusion】The effects of phosphorus and sulfur interaction on selenium enrichment of flue-cured tobacco varied due to the growth period and different organs of flue-cured tobacco. In the designed application amount of phosphorus and sulfur, the interaction of phosphorus and sulfur showed a positive effect on the increase of selenium content of flue-cured tobacco.