四川昭觉县中部乡镇表层土壤硒地球化学特征

硒元素是人体必需的微量元素之一，食用富硒农产品是人体获取和补充硒元素的主要途径，调查区域硒地球化学特征是有效地利用富硒土地资源以及开发富硒农副产品的重要依据。本文选择四川省昭觉县域内较为重要的农耕乡镇采集表层土壤样品，采用原子荧光光谱法、X射线荧光光谱法、电感耦合等离子体质谱/发射光谱法等方法测定1328件土壤、19件玉米及20件土豆中硒等地球化学指标含量，利用相关分析与统计学等方法，结合距离加权反比插值法，探讨研究区硒含量、分布和影响因素等地球化学特征，评价土壤与作物的富硒情况及安全性。结果表明：(1)研究区表层土壤硒含量范围为0.04～1.50mg/kg,平均值为0.33mg/kg,划定富硒土壤面积为7.23km~2,占全区土壤面积的30.31%,玄武岩发育的土壤硒含量最高，平均值为0.4mg/kg,表明区内地质背景与土壤硒含量密切相关，区内富硒土壤主要受含玄武岩夹苦橄岩、凝灰质砂泥岩的峨眉山玄武岩组地层控制；(2)不同的用地类型和土壤类型对硒元素的富集能力不同，人为农业活动导致土壤对硒的吸附能力下降，黄棕壤土层中黏粒或铁氧化物等易与硒结合富集；酸性土壤中硒含量与pH值成反比；土壤...

Geochemical Characteristics of Selenium in Surface Soil of Central Townships in Zhaojue County, Sichuan Province

BACKGROUND: Selenium (Se) is one of the essential trace elements for humans, and an important way for humans to obtain and supplement selenium is by eating natural selenium-enriched agricultural products. The geochemical characteristics of selenium in the survey area are an important basis for the effective utilization of selenium-enriched land resources and the development of selenium-enriched agricultural and sideline products.OBJECTIVES: To investigate the geochemical characteristics of selenium content, distribution and influence factors in the study area.METHODS: Soil and crop samples were collected from a central village of Zhaojue County, Sichuan Province. AFS, XRF and ICP-MS were used to determine the contents of elements including Se, Al₂O₃, TFe₂O₃, SiO₂, OrgC, and pH values. Geochemical characteristics of selenium content, distribution and influencing factors in the study area were investigated using statistical and correlation analysis.RESULTS: (1) The soil selenium content in the study area ranged from 0.04 to 1.50mg/kg,with an average value of 0.33mg/kg. The delineated selenium-enriched soil area was 7.23km², accounting for 30.31% of the total soil area. The selenium content of the soil developed in basalt was the highest, with an average of 0.4mg/kg, indicating that the geological background in the area was closely related to the soil selenium content. The Se-enriched soil in the area was mainly controlled by the Emeishan basalt Formation, which contained basalt intercalating with picrite and tuffaceous sand and mudstone. (2) The enrichment capacity of selenium varied in different land utilization and soil types. The absorption capacity of selenium in soil decreased due to human agricultural activities. Clayey particles or iron oxides in the yellow-brown loam layer were easy to combine and enrich selenium. The selenium content in acidic soil was inversely correlated to pH value. There was a significant positive correlation between soil organic matter and selenium content. Soil texture had a certain effect on selenium content. (3) Corn and potatoes from selenium-enriched soils had very low selenium content.CONCLUSIONS: During the exploitation and utilization of selenium-enriched soil, organic fertilizer should be added in time and soil pH should be adjusted in agricultural areas such as dry land and paddy field, and other agricultural products should be developed by using selenium-enriched resources.