DISTRIBUTION OF SOIL SELENIUM AND ITS RELATIONSHIP WITH SOIL PROPERTIES IN WANJINSHAN OF BAOQING COUNTY, HEILONGJIANG PROVINCE

The study collects 628 topsoil samples at a density of 4 points/km² in farm and forest areas of Wanjinshan Township, Baoqing County, to analyze 28 chemical indexes including Se etc. The results show that the average Se content in the topsoil is 0.28×10^-6, ranging from 0.065×10^-6 to 0.51×10^-6, with the Se-rich land accounting for 3.16%, Se-sufficient land 92.3%, potential Se-deficient land 4.3%, Se-deficient land 0.24% and no Se poisoning area. Black soil type has the highest Se content, while swamp soil type has the lowest Se content. The Se contents in different land use patterns are ranked as follows: dry field > paddy field > shrub land > arbor land > grassland and other land. Correlation analysis indicates that soil TOC and clay content promote the enrichment of Se, while pH has a limited influence on Se content but significant effect on Se availability.