Status of Fluorine in the Soils of Tea Gardens in Brick Tea Areas of Hunan, Hubei Provinces and Its Affecting Factors

The water soluble F, total F content, soil pH, organic matter contents and exchangeable cation contents of tea garden soils and the corresponding tea samples in brick tea areas of Hunan, Hubei provinces were determined. The results showed that the total F content of soils was a bit lower than the average F level of China(440 μg/g), and obviously higher than the F level in the world(200 μg/g). The soil F content is highest in 0~5 cm depth, relatively low in 0~20 cm depth, lowest in 20~40 cm depth. F could be accumulated within tea plant, so the F content of tea is correlated to leaf maturity, the older the leaves are, the higher the fluorine content is. The high positive correlation was found between the water soluble F content and pH, the exchangeable K、Ca、Mg、Na content, the available P; the high negative correlation was between the water soluble F and the organic matter, the exchangeable Al 、Mn contents.