Geochemical characteristics of selenium in the soil-plants system of Enshi area, Hubei Province

The survey of selenium content of soil in such typical agricultural areas as Bajiao, Changping and Yutangba was carried out. On the basis of the investigation and the comparison with the Se-rich soil quality standards, Bajiao and Yutangba were found to be Se-rich and highly Se-rich areas respectively. Based an investigation of the physical and chemical properties of soil, speciation and plants growing in the soil, the authors conducted a preliminary study of the migration and transformation of selenium in the soil-plant system. Three aspects of results have been obtained. First, the selenium content of soils and plants is quite high in Yutangba but rather low in Changping. Second, the physical and chemical properties of soil have a certain influence on the selenium absorption of plant, with different types of plants showing remarkable difference in the absorption and enrichment of selenium. Third, speciation analysis shows that the bioavailability of selenium in Yutangba soil is higher than that in Bajiao, while the Bajiao soil has a higher proportion of residual selenium, showing that its bioavailability of selenium is lower than that of Yutangba area.