安徽省宁国市土壤和农产品硒地球化学特征及影响因素

以安徽省宁国市全域表层土壤和主要农产品为研究对象,系统采集了6 278件土壤样品和216件农作物样品,研究了土壤全硒含量的分布特征及其主要影响因素,分析了土壤有效硒含量特征和农产品硒含量特征。结果表明:宁国市土壤全硒含量平均值为0.645 mg/kg,富硒土壤样点数和面积占比分别为57.45%、70.30%。土壤硒含量主要受成土母质控制,震旦系和寒武系下统发育土壤硒含量显著高于其他成土母质;不同土地利用方式对土壤硒含量有一定的影响,园地和林地土壤比水田、旱地土壤更易富集硒元素;土壤硒含量与有机质、重金属元素含量存在显著的正相关关系(P<0.01),与土壤p H没有显著相关性。土壤有效硒含量平均值为0.023 mg/kg,水稻、山核桃、茶叶中硒含量平均值分别为0.065、0.022、0.074 mg/kg,水稻、山核桃富硒率高达24.04%和54.88%,富硒山核桃具有广阔的开发前景。

Geochemical Characteristics and Influencing Factors of Selenium in Soils and Agricultural Products in Ningguo City, Anhui Province

In this study, 6 278 topsoil samples and 216 samples of main agricultural products were collected in Ningguo City,Anhui Province, and the total and effective selenium contents in the soil and crop samples were determined, and then the spatial distribution characteristics of soil total selenium content and its main influencing factors were analyzed.The results showed that the average contents of total selenium in soils was 0.645 mg/kg, the percentage of selenium-rich grade was 57.45% in sample number and 70.30% in area, respectively. The content of total selenium in soil was mainly determined by the parent materials, and selenium content were significantly higher in the soils derived from the Sinian and lower Cambrian parent materials than those from the other geologic ages. Furthermore, selenium contents were different in soils under different land use types, which were higher in the orchard and forest than those in the dryland and paddy field. Correlation analysis showed that soil selenium content had significant positive correlations with the contents of organic matter and heavy metals (P<0.01) but no correlation with soil pH. The average contents of effective selenium was 0.023 mg/kg in soils, and the average selenium content was 0.065 mg/kg in rice, 0.022 mg/kg in Carya cathayensis and 0.074 mg/kg in tea. The selenium enrichment rate was as high as 24.04% in rice and 54.88% in Carya cathayensis, indicating that the selenium-rich Carya cathayensis has a broad prospect of market development.