Abstract:

A detailed investigation of selenium concentration and distribution in the soil was carried out in Qingtang-Meijiao area, South Jiangxi Province. 889 topsoil (0-20 cm) samples and 72 crop samples were collected. We systematically analyzed the distribution of selenium in the soils and crops, the relation between the distribution characteristics and soil parent materials, land-use type, physical and chemical properties of soils. Results of the analysis show that the average contents of soil selenium in the study area was 0.44 mg·kg^-1, including 48.59% in sufficient selenium state, and 42.86% in rich selenium state. In spatial distribution, the area which showed deficiency or potentially insufficient of selenium is only sporadically distributed. The contents of selenium in topsoil inherited the soil parent material partly. Furthermore, the concentrations varied in diffe-rent land use types. Correlation analysis showed that selenium contents in soils had a significant positive correlation with organic material and a faint correlation with pH value. Peanut and rice have higher selenium enrichment rates. The rich selenium rates of the peanut and the early season rice both meet the national food safety standards. Only late season rice expressed excessive heavy metals. By comparing data, we found that the over-standard rate of heavy metals in late season rice collecting from selenium-rich areas was far lower than those from non-selenium-rich areas. It is indicated that the selenium in soils can partly reduce the enrichment effect of heavy metal elements in late season rice.

Key words: South Jiangxi Province, soil, selenium concentration, geochemical distribution characteristics, influence factor