青海西宁及周缘地区土壤硒地球化学特征及成因研究

Study on the geochemical characteristics and genesis of soil selenium in Xining and its surrounding areas of Qinghai province

本研究以青海西宁及周缘地区27900km2,1∶250000土地质量地球化学调查成果为基础,总结不同土壤类型、成土母质、土地利用类型土壤中硒含量特征,分析其影响因素,并对土壤硒成因来源进行研究。研究结果表明,青海湖北部土壤硒在风化成壤过程中逐步富集,土壤中硒含量与有机质存在显著相关性,有机质含量增加和土壤粒度的变细是形成富硒土壤的主要原因;达坂山一带和拉脊山一带土壤中硒与铜和硫存在显著相关性,中基性火山岩和含煤碎屑岩是土壤硒的主要来源,有机质吸附作用使土壤硒富集;有机质吸附作用使土壤中硒再次富集是普遍存在的现象。

This study is based on the survey results of 27 900 km 2 with 1:25 million land quality geochemistry in Xining and its surrounding areas of Qinghai,which summarized the characteristics of selenium content in different soil types,soil parent material and land use types,and analyzed the influencing factors.This study also studied the origin of selenium in high selenium content soil.The results showed that soil enriched step by step in the process of soil weathering and soil formation in the northern Qinghai lake,the content of selenium in the soil was significantly correlated with organic matter,the increase of organic matter content and the thinning of grain size were the main reasons for the formation of high selenium soil.Selenium in the soil of Da sakaka mountain and La Ridge mountain had a significant correlation with copper and sulfur,middle-base volcanic rocks and coal-containing debris rocks provided the main source of selenium for the soil,and organic matter adsorption and fixation made the soil selenium enriched;and it is a common phenomenon that organic matter adsorption can enrich selenium again in soil.