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赤壁市典型砖茶种植区土壤中氟的分布特征及污染来源研究

Distribution Characteristics and Pollution Sources of Fluoride in Typical Brick Tea Garden Soil in Chibi City

  • 摘要: 茶树是氟的超富集植物,茶树中氟的积累与外部氟浓度之间呈现线性相关性。茶叶中的氟主要来源于土壤,而土壤中氟的有效性是由水溶性氟形态含量决定的,极易被茶树吸收累积于茶叶中。土壤样品分析结果显示,成土母质是影响土壤全氟含量的决定性因素,茶园不同类型土壤表层含氟量分布规律表现为棕红壤>幼年红壤>黄红壤,该种植区表层土壤含氟量总体呈现由北到南逐渐降低的变化趋势。在土壤呈酸性条件下,pH值变化对土壤中水溶性氟含量影响较小。外源氟样品分析结果显示,土壤中氟主要来源于地层及长期大量施用的洋丰、西洋复合肥,大气沉降、茶园灌溉水及农药施用均非茶园表层土壤氟元素的物质来源,建议后期茶园增施有机肥、氮肥,减少复合肥的使用,有利于降低砖茶含氟量。

     

    Abstract: Tea plants are known hyperaccumulators of fluorine, and accumulate quantities of fluorine proportional to the concentration of fluorine in the environment. The primary source of fluorine in tea is water-soluble fluorine compounds in the soil, which are readily absorbed and accumulated in the leaves of tea plants. The Analyses of soil samples indicate that the parent material of soil significantly influences the total fluorine content. The distribution of fluorine in the surface soil of different soil types within the tea gardens follows this order: brown red soil>young red soil>yellow red soil. Generally, fluorine content in the surface soil of the planting area displays a decreasing trend from north to south. Under acidic conditions, pH variations minimally impact the concentration of water-soluble fluorine in the soil. Exogenous sample analyses reveal that the primary sources of soil fluorine are geological formations and the prolonged and intensive use of foreign and Western compound fertilizers. Atmospheric deposition, along with water used for irrigation and pesticides in tea gardens, do not constitute significant sources of fluorine in the surface soil. To mitigate fluorine levels in brick tea, it is advisable for tea gardens to increase the use of organic and nitrogen-based fertilizers and decrease compound fertilizers.