Spatial differentiation characteristics of selenium in Se-rich yellow soils developed from black shale and coal bearing formations in Guizhou Province
Studying the differentiation characteristics of selenium(Se)in Se-rich soils is of great significance to promoting Se-rich agriculture in Guizhou Province.This study took yellow soils developed from the Permian coal seam in southwestern Guizhou and the Cambrian black rock layer in Zunyi as the research object,and studied the total content,the chemical speciation and the available content of Se in these soils,as well as their influencing factors.The results showed that the average total contents of Se in yellow soils developed from the black shale formation and the coal-bearing formation were 0.76 mg/kg and 0.99 mg/kg,respectively.The organic bound state,residual state and Fe-Mn oxide bound state were the main forms of Se in these yellow soils.The average bioavailable Se contents in yellow soil developed from black shale formation and yellow soil developed from coal bearing formation were 67.2 μg/kg and 71.8 μg/kg,respectively,accounting for only 8.57％and 6.98％of their total Se content.Plant-available Se in soil,including Se in the water-soluble,exchangeable,and carbonate-bound states was very low.In addition,the yellow soil developed from the black shale formation was generally acidic(average pH 5.88),and its bioavailable Se was mainly affected by organic matter;the yellow soil developed from the coal-bearing formation was generally neutral(average pH 6.84),and its bioavailable Se was mainly affected by soil pH.The affecting factors for Se availability in the two types of Se-rich yellow soils are significantly different.Therefore,the development of Se-rich agriculture needs to be adapted to local conditions.
万方数据
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