Mass fraction of fluorine in some tea gardens of Hunan and Zhejiang

The contents of water-soluble F , total F in the soils of tea gardens and the corresponding tea samples in Hunan Province and Zhejiang Province were determined .The results showed that the soil contained total F of (383.83 79.24)mgkg-1 in 0 -20 cm depth , and (347.44 115.95)mgkg-1 in 20 -40 cm depth in Hunan Province , which was a bit lower than the average F level in China (440 mgkg-1), but obviously higher than the F level in the world (200 mg kg-1).The available F content approximately accounted for 0.03 %-0.06 % of the total F .The F content in 0 -20cm depth were higher than that in 20 -40 cm depth .The content of F in tea soil was also low in Zhejiang Province .It was clear from the results that a high correlation was found between F contents (y)in the leaves and water-soluble F content (x)in tea soil , expressed as :y =306.94 x + 139.31 (n =35 , r =0.34＊ , P 0.05), and between F content (y )in mature leaves and new shoots (z),described by the equation :y =4.91z +371.38 (n =35 , r =0.72＊＊ , P 0.01), so F could be accumulated within the tea plants .The contents of F in the new shoots in Hunan and Zhejiang Provinces were (168.26 83.73)mgkg-1 and (81.58 27.20)mgkg-1 respectively , which were at a low level ;the contents of F in mature leaves were (1 197.09 569.95)mgkg-1 and (1 212.72 342.28)mg kg-1 respectively , which were high . The content of water-soluble F in tea soil was a bit lower than that in untilled soil , there being no significant difference (P 0.05).[ Ch , 6 tab .19 ref .]