大庆龙凤湿地土壤硒的结合态与分布特征

为了解大庆龙凤湿地土壤硒的含量、形态,应用连续浸提的方法研究了大庆龙凤湿地保护区4个样区20个样点4个不同层次的土壤中硒的含量、形态、剖面分布,并对土壤中影响硒元素沉积量的相关理化性质进行了测定。结果表明,大庆龙凤湿地土壤全硒含量在垂直分布上没有明显的规律,变幅在121～150μg/kg之间,属于少硒土壤,在各种结合态硒中,水溶性硒仅占土壤全硒含量的1.5%～3.3%,交换态硒占3.6%～7.4%,有机态硒占24.0%～43.9%,酸溶态硒、硫化态硒和残余态硒3种无效态硒共占50%以上。土壤有机质、pH值及土壤粘粒是影响土壤硒含量的主要因素,并且由于土壤有效硒含量低、无效硒比例高导致硒的利用率低,这可能是本地区人与生物缺硒的主要原因之一。

Combination Forms and Distribution Characteristics of Se in Daqing Longfeng Wetland Soils

In order to understand the amount,species and distribution of selenium(Se) in Daqing Longfeng wetland soil,the contents of Se were measured by a method of successive extraction,and the physical and chemical properties of soil that affects the deposition of Se were determined.The results showed that Se in Daqing Dragon wetland soil is of normal level,and Se contents showed obvious rules of variation in the vertical direction,varying between the 121~150 μg/kg.Among several kinds of Se forms,water-soluble Se,exchangeable Se and organic Se account for 1.5%~3.3%,3.6%~7.4%,24.0%~43.9% of the total Se,respectively,while unavailable Se including acid-soluble Se,sulphide Se and residual Se accounts for more than 50% of the total Se.Soil factors such as organic matter,soil pH and clay fraction play relatively important roles.However,due to the low proportion of effective Se and the high proportion of ineffective Se in soil,selenium is low in availability.It is the reason that people and living organisms in this region are insufficient in Se.