Analysis of selenium content characteristics, origin and main controlling factors of migration transformation in soil−plant system, in west Xingkai Lake

Selenium and its organic compounds have important biological activities and special health care functions for living organisms, and research on selenium genesis and transport of selenium in selenium-enriched soils is of great scientific and economic significance for selenium-enriched land utilization and selenium-enriched functional product development.Based on the regional geological features, soil data and plant seed data, and research on the spatial distribution and genesis of soil selenium, and explored the main controlling factors of selenium transport and transformation in the soil-plant system by using geostatistics, correlation and bioconcentration coefficients. The soil selenium content ranged from 0.11 mg/kg to 0.70 mg/kg, with an average value of 0.37 mg/kg, and the content characteristics and spatial distribution were mainly controlled by the soil-forming parent material; Fujin Formation black rock series was the material basis for the formation of selenium-rich soils and the initial source of selenium, and the favorable palaeoclimatic environment in the later stages of evolution promoted the continued weathering of the black rock series, which provided a rich source of selenium for the soils; the plant enrichment capacity of the BCF_rice/soil> BCF_maize/soil, and the average seed selenium content Se_rice> Se_maize,and the correlation between the selenium content and soil physicochemical indexes revealed that selenium transport and transformation in the soil-plant system are regulated by soil mineral composition and soil environment. Soil selenium mainly comes from Fujin Formation black rock series and its weathered materials, adsorption/resolution of clay minerals as the main controlling factor of selenium transport and transformation in soil-plant system; 6550.68 hm² of natural selenium-enriched land was delineated, which would provide a geomorphological basis for the scientific utilization of selenium-enriched land and development of selenium-enriched functional products, effectively support services for local economic development and disease prevention.