贵州省习水县表层土壤硒地球化学特征及影响因素分析

Chemical characteristics and influencing factors of selenium globules in surface soil of Xishui County,Guizhou Province

本文在贵州省习水县1∶50000耕地质量地球化学调查评价工作基础上,经过取样调查分析,查明了习水县境内耕地表层土壤的环境综合质量及硒的地球化学分布特征,初步探讨了影响表层土壤硒含量高低和分布的因素。结果表明,习水县耕地土壤总体呈中性—酸性,土壤环境综合质量较好。全县耕地表层土壤硒平均含量为0.44 mg/kg,富硒(0.4~3.0 mg/kg)占比55.53%,在全县均有分布。研究区的富硒土壤分布与成土母岩有较大的关系,二叠系龙潭长兴组含煤地层发育的土壤硒含量最高可达1.374 mg/kg,最低为上侏罗统蓬莱组发育的土壤,为0.285 mg/kg;不同的土壤类型,石灰土和黄壤的硒含量较高,分别为0.75 mg/kg、0.58 mg/kg,紫色土的含量相对较低,为0.31 mg/kg;不同的土地利用类型中,茶园的硒含量最高,为0.69 mg/kg,水田最低,为0.40 mg/kg;Pearson相关性分析结果表明,有机质含量与土壤硒呈正相关关系,pH与土壤硒无显著相关性。

In accordance with the 1∶50000 geochemical survey and evaluation of cultivated land quality in Xishui County,Guizhou Province,it conducted the sampling survey and analysis to identify the comprehensive environmental quality and geochemical distribution characteristics of selenium in the topsoil of cultivated land in Xishui County,which also preliminarily explored the factors affecting the content and distribution of selenium in the topsoil.From the results,it showed that the neutral to acidic soil of cultivated land in Xishui County was gener⁃ally presented,and the overall quality of the soil environment was relatively good.The average selenium content in the topsoil of cultivated land in the county is 0.44 mg/kg,in which the selenium enrichment(0.4-3.0 mg/kg)accounts for 55.53%,being distributed throughout the county.The parent rock of the soil closely influences the distribution of selenium enrichment soil in the study area.The highest selenium content in the soil developed from the coal bearing strata of the Longtan Changxing Formation in the Permian system can reach 4.280 mg/kg,while the lowest selenium content in the soil developed from the Penglai Formation in the Upper Jurassic system is 0.285 mg/kg.In terms of various soil types,it’s found that the selenium content of calcareous soil and yellow soil is higher,which is 0.75 mg/kg and 0.58 mg/kg respectively,while that of purple soil is relatively low,reaching 0.31 mg/kg.In different land use types,the selenium content in tea gardens is found to be the highest at 0.69 mg/kg,while paddy fields have the lowest selenium content at 0.40 mg/kg.According to the Pearson correlation analysis results,a positive correlation between organic matter content and soil selenium is shown,while there is no significant correlation between pH and soil selenium.