Characteristics Of Tea Plantation Soil Environmental Quality Around The Dongting Lake In Hunan Province

The soil quality is the basic condition of ensuring ago-product quality. The cropquality is closely related to the soil environmental quality in agriculture growing area. Taking thehilly region of Dongting lake in Hunan Province as main research area, where the soils derivedfrom several main soil parent materials, the content and the distribution characteristics of soilheavy metals, the relationship between the content of soil heavy metal and the tea quality werestudied in this region, using methods that were the investigating and sampling, laboratoryanalyzing, computer technology, model evaluation, ect. While the soil environmental quality wasevaluated with the pollution index method. The result showed as the follows:1. The content of heavy metals was lower than the standard of Environmental Qualificationof Nuisance Free Tea Producing Area (NY5020-2001) and State Environmental QualityStandard for Soils in PRC (GB15618-1995) in tea plantation soils that derived from several mainsoil parent materials in hilly region of Dongting Lake in Hunan province. The difference of thecontent of heavy metals was observed, the reasons showed as follows, such as the different ofsoil parent materials, fertilization, and management practices. The highest content of soil Cr is254.4±94.2mg/kg in tea plantation of Junshan, while the lowest is 33.7±25.3 mg/kg in teaplantation of Kaihui, and the former was nearly 8 times more than the latter. The content of soilCr in other tea plantation was lower than the standard of NY5020-2001. The average content ofsoil As was 12.8 mg/kg, and the content was from 1.8 to 52.3 mg/kg, only 1.96% higher than thestandard of NY5020-2001. The content of Pb, Hg, Cd, Ni, Zn, Cu was lower than the standard ofNY5020-2001 or GB15618-1995, and the region was the very place to develop pollution-free teaplantation.2. The vertical change in profiles of the tested soils in tea plantation varied with differentheavy metals. First, the Hg content increased with increasing depth in the profile of Changchuntea plantation; Second, it decreased with increasing depth in the profile of Yanglu and Junshantea plantation; third, the content of Zn was maximum or minimum in subsurface horizon of theprofiles in tea plantation of Junshan, it was maximum in 15-30cm horizon of the profile in teaplantation of Junshan.3. The pollution index was used to evaluation the soil environmental quality around theDongting Lake. The results showed that: the integrated pollution index was less than 1 in thesurface soils and it was slightly polluted in the tea plantation of Junshan, and the index was lessthan 0.7 in other tea plantations and it was in the safe class. The pollution index of Cr was higherthan 1 in 0-15 cm and 60-100 cm horizon of the profile in tea plantation of Jinhua and Junshan, however, the integrated pollution index was less than 0.7 in tea plantation of Jinhua, and it canbe divided the safe class. The integrated pollution index was 1.386 in the tea plantation ofJunshan, it probably might constitute tea pollution, so correspond methods should be used assoon as possible to eliminate the pollution.4. The Pb content in tea was from 0.092mg/kg to 1.212mg/kg, and the Cu content was from8.5mg/kg to 16.9mg/kg, they were less than the standard of National Agriculture Standard forPollution-free Argo-product in Tea (NY5017-2001), The Cd content in tea was from 0.032mg/kgto 0.072 mg/kg, and the As content was from 0.001mg/kg to 0.006mg/kg, they were both lessthan the standard of Agriculture Standard of Cr, Cd, Hg, As and Fluoride (NY659-2003).5. The statistic analysis showed that in the hilly region of Dongting Lake, the content ofheavy metals in tea was not significantly correlated with it in soils except Pd, and the content ofCd, As, Cr in tea was influenced lightly by which in soils.