Selenium geochemistry of soil and development potential of Se-rich soil in Xingkai Lake Plain

The results of geochemical survey of land quality show that the soil in Xingkai Lake Plain is generally sufficient in selenium, and the area of Se-rich soil is less than 1%. The distribution of Se in soil has a good inheritance from the parent material of soil. The highest average Se content is found in the soils originated from the Neogene Fujin Formation (N₁f), with an average value of 0.375 mg/kg. This stratum controls the main distribution of Se-rich soils in the study area. The lowest Se content is found in the soils originated from the Carboniferous Beixing Formation tuff, with an average value of 0.183 mg/kg. Meanwhile, soil Se content is also affected by geochemical environment, soil type, soil properties and other natural conditions. The Se content of white clay soil is the highest, and that of dark brown soil is the lowest.Se is significantly positively correlated with soil Corg, N, P, TFe₂O₃, S, As, Cr, Cu, Hg, Pb, Cd and Ni, and negatively correlated with pH, CaO, Na₂O and Zn.In addition, the comprehensive quality of land in the study area is excellent. The five potential Se-rich areas are in line with the AA green food producing areas, and natural Se-rich rice has been found, which has great potential for the development of Se-rich agricultural products.