江苏省典型茶园土壤硒分布特性及其有效性研究

Distribution and Availability of Selenium in Typical Tea Garden of Jiangsu Province,China

通过实地调查,研究了江苏省22个典型茶园表层土样和12个剖面土样的全硒含量,分析了土壤全硒含量分布特性、有效硒含量及其影响因素。结果表明,江苏省典型茶园土壤全硒含量在0.10～1.78mg·kg-1之间,平均为0.50mg·kg-1,高于全国平均值。其中,宜兴地区土壤全硒平均含量为0.88mg·kg-1,明显高于其他地区的0.25mg·kg-1,但前者土壤硒活化率仅为4.94%,明显低于江苏省平均值9.04%。宜兴地区虽然土壤供硒潜力巨大,但要充分利用富硒土壤开发、生产富硒茶必须提高土壤中硒的活化率和可利用度。土壤有效硒与土壤pH值、CEC呈极显著正相关,在实际生产中可通过提高土壤pH值等改善土壤环境条件的方法来提高土壤硒的有效性,从而提高茶叶中硒的含量。研究区内硒在表层土壤中的相对含量趋向增加,生物积累大于淋溶作用。

As a trace element selenium（Se） is of great importance on human health and its contents in environment directly affects the health and safety of human beings,animals and plants.Concentrations,distribution,and availability of Se in typical tea garden soils in Jiangsu Province were investigated and the governing factors were analyzed.12 vertical profile samples and 22 top layers samples were collected.The results showed that the total Se content ranged from 0.10 mg·kg-1 to 1.78 mg·kg-1 in tea garden soils of Jiangsu with an average of 0.50 mg·kg-1 which is higher than the national average value.The average Se concentration in samples from Yixing（0.88 mg·kg-1） was significantly higher than that from other sampling sites（0.25 mg·kg-1）.This indicated there existed relatively Se-rich top soils in Yixing,southern Jiangsu though Se in top soils was not rich in most areas of Jiangsu.Nevertheless,the activity index of Se was 4.94% in samples from Yixing.It was remarkably lower than the average value in Jiangsu（9.04%）,which puts a disadvantage to produce Se-rich tea in Yixing.Availability of Se positively correlated to the pH and CEC of the soil.Therefore,increasing the soil pH or other practices of improving the conditions of soil in agricultural production could be potentially effective to culture natural Se-rich tea in Yixing.Se content was higher in the top layer of the soils indicating that biological accumulation plays a more significant role than eluviation in control the vertical distribution of Se.The results of this study can serve as a practical reference for both reasonable planning of the tea production and development of Se-rich tea industrialization in Jiangsu.