三峡库区土壤中硒、碘、氟分布特征与规律研究

利用土壤表层样分析成果，研究了三峡库区土壤中硒、碘、氟等生命元素在不同土壤中的含量分布特征，探讨了不同地貌、植被覆盖条件下对其元素分布的影响，结果表明：三峡库区土壤的硒、碘含量较低，而氟含量较高，是低硒、低碘、高氟地区。地质背景是土壤硒、碘、氟的主要来源，灰岩分布区土壤中硒、碘、氟含量均高于其它类母岩分布区土壤，泥岩分布区硒、碘含量最低，砂岩分布区的氟含量最低。除受地质背景控制外，碘、氟还受土壤分布高程、植被等因素的影响。土壤分布高程越低，地形坡度越小，土壤中碘、氟含量越低。针叶林覆盖对土壤碘、氟起富集作用。土壤硒含量受其它因素的影响较土壤碘、氟小。

THE DISTRIBUTION CHARACTERISTICS OF Se,I,F IN SOILS IN THE DISTRICT OF THREE GORGES RESERVOIR

Based on the analysis of shallow soils, the distribution regularity of Se, I, F in soils in the district of Three Gorges reservoir, and has been discussed in relation to geolgy, soil and geography. The results show that the contents of Se, I are low and F is high in the district of Three Gorges reservoir compared with other provinces or cities. And Se,I,F in soils mainly come from rocks. The soil formed from limestone enrich with Se,I,F elements than other rocks, the soil formed from marlite containing the least Se、I, and the soil formed from sandstones contains the least F. Apart from geological background, F,I are controlled by the topographical feature, the altitude, the vegetation covering types, and the land where soils are distributed. For instance, the lower the altitude or the lesser the gradient where soils are distributed, the lower the Se and F contents in the soils. And the soil covered by conifer forest has high contents of I,Se and the paddy field soil contains the least Se,I,F than other kinds of land.