巴彦淖尔市临河区狼山镇和新华镇一带富硒土壤地球化学特征及影响因素

Geochemical Characteristics and Influencing Factors of Se-Rich Soils in Langshan and Xinhua Towns,Linhe District,Bayannur City

内蒙古自治区巴彦淖尔市临河区狼山镇和新华镇一带发现大面积硒高含量区。为研究该地区富硒土壤的地球化学特征及土壤硒含量的控制因素,采集6250件表层土壤样品,并设计5条土壤垂直剖面进行化学元素测试分析。结果表明,研究区耕地土壤硒含量介于(0.06~0.77)×10^(-6)之间,平均含量为0.32×10^(-6),硒的背景值为0.32×10^(-6),是巴彦淖尔市表层土壤背景值(0.20×10^(-6))和中国土壤背景值(0.20×10^(-6))的1.6倍,且研究区耕地土壤中达到富Se水平(0.4×10^(-6)以上)的样品数为1072个,占全部采样点位的17.2%,表明研究区耕地土壤中硒含量相对较高。研究区土壤中硒和营养元素及重金属元素存在正相关关系,与土壤pH存在一定的负相关关系;硒在土壤垂直方向上分布总体上表现出表聚性特征,随剖面深度增加,硒含量逐渐降低。表层土壤中硒含量主要受土壤有机质含量影响,土壤垂直方向上硒含量主要受有机质与粘土矿物影响。

A large area with high Se content was found in Langshan Town and Xinhua Town,Linhe District,Bayannur City,Inner Mongolia.In order to study the geochemical characteristics of Se-rich soil and the controlling factors of soil Se content in this area,6250 surface soil samples were collected in this area,and five soil vertical profiles were designed for chemical element test and analysis in Langshan Town and Xinhua Town,Bayannur City.The results show that the content of selenium in cultivated soil in the study area ranged from 0.06×10^(-6) to 0.77×10^(-6),with an average content of 0.32×10^(-6),and the background value of selenium is 0.32×10^(-6),which was 1.6 times that of topsoil in Bayannur City(0.20×10^(-6))and Chinese soil(0.20×10^(-6)).The number of samples with Se rich level(more than 0.4×10^(-6))in cultivated soil in the study area was 1072,which accounts for 17.2%of all sampling points,indicating that the content of selenium in cultivated soil in the study area is relatively high.There is a positive correlation between selenium and nutrient elements and heavy metal elements,and a negative correlation with soil pH.The distribution of selenium content in the vertical direction of soil generally shows the characteristics of surface aggregation.With the increase of profile depth,the content of selenium in soil gradually decreases.The content of Se in topsoil is mainly affected by the content of soil organic matter,and the content of Se in soil vertical direction is mainly affected by organic matter and clay minerals.