江西省鄱阳湖流域根系土硒形态分析及其迁移富集规律

AN ANALYSIS OF SPECIATION OF SELENIUM AS WELL AS ITS TRANSFORMATION AND ENRICHMENT IN ROOT SOIL OF POYANG LAKE BASIN,JIANGXI PROVINCE

对江西省鄱阳湖流域根系土中硒的形态分析表明,根系土中Se的强有机态、腐植酸结合态约占Se全量的66.23%,残渣态占12.32%,3种形态均与根系土Se全量呈极显著的线性正相关。根系土Se全量受pH值的影响不明显,但受有机质含量的影响很大,线性回归关系极显著,说明岩石风化、土壤发育过程中,有机质吸附Se,致使Se较其他元素流失比例少,造成根系土中Se相对富集。同时,提出了利用全量Se推导Se各形态值的方法,建立了土壤Se全量与各形态间的关系模型和决定土壤有效态Se的公式,建议在评价土壤Se时只用考虑有机结合态Se、残渣态Se、水溶态Se和全量Se。

Selenium speciation in root soil samples collected from the Poyang Lake basin of Jiangxi Province was investigated in this paper.The results show a significant positive correlation between the species and total amounts of selenium in root soil.The residue species of selenium occupies 12.32% of total selenium,and the species of bound-state humic acid approximately accounts for 66.23% of the total amount of selenium in root soil.Meanwhile,selenium abundance in root soil insignificantly varies with the change of pH value but is significantly influenced by organic content.It is held that the process of selenium adsorption in soil organic substance and clay mineral causes selenium enrichment in root soil.This paper has proposed a method for estimating speciation concentration of selenium according to the total selenium and established a formula to calculate available selenium content with given data of selenium abundance and speciation in soils.In addition,a suggestion is put forward that only selenium species of organic bound,residue,water soluble and total amount of selenium should be considered in soil selenium assessment.