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    福建铁观音茶园生态地球化学特征

    Eco geochemical characteristics of the Tieguanyin tea gardens in Fujian Province

    • 摘要: 提要: 东南沿海是铅等重金属的地球化学高背景区。该地区广泛分布酸性红壤, 酸雨沉降、不适当施肥导致土壤酸化以及由此引发土壤重金属生态风险令人关注。以福建省铁观音主产区为研究区, 采集了79个茶园的表层和亚表层土壤样、茶叶样品, 测定了重金属元素以及土壤常量元素和理化指标。研究表明, 福建铁观音茶园土壤中Hg、Pb、Se、Zn高含量主要由地质背景所引起, 土壤常量组分、有机质、酸碱度等理化条件对土壤元素含量有一定的影响; 铁观音茶树老叶中As、Cd、Cr、Hg、Se、Pb、F等非植物营养元素含量明显高于嫩叶, 显示这些元素随植物生长逐渐累积的特征, 而嫩叶中植物生长必需的营养元素Cu、(Ni)、Zn则高于老叶, 反映出微量营养元素在茶叶生长部位相对富集的特征; 多数情况下土壤与茶叶间元素含量相关性差, 说明茶树对土壤元素的吸收累积受到多种复杂因素的影响。研究表明茶叶与土壤Pb、Cr具有显著正相关性, 为建立铅污染土壤生态效应预测评价模型提供了基础依据。

       

      Abstract: Abstract: It has been identified that a high geochemical background of some heavy metals including Pb exists in the southeastern part of China. There is a potential eco?geochemical hazard risk from heavy metal mobilization caused by soil acidification due to acid precipitation and improper manure. The main production area of Tieguanyin tea was selected for this study. Surface and sub?surface soils as well as tea leaves were collected from totally 79 tea gardens. Heavy metals in soils and tea leaves, major elements and physicochemical indicators of soil samples were determined. It is found that Hg, Pb, Se and Zn in tea garden soils are higher than their geochemical backgrounds of national soils, and this is attributed mainly to soil?parent rocks controlled by geological setting. However, soil properties including particle composition, organic material content and pH also play important roles in trace element concentration. Some non?nutrition elements for vegetation including As, Cd, Cr, Hg, Se, Pb and F are accumulated in matured leaves compared with their values in sprouts. Nutritive elements such as Cu, Ni and Zn seem to accumulate in sprouts to meet the demand of tea growth. Although the relationships between soil and tea leaves are quite complicated for most elements, there exists obvious positive correlation between soils and tea leaves in Cr and Pb content. This discovery provides the mathematical basis for establishing a model for forecasting lead impact on ecosystem.

       

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