武夷山市5种类型茶园土壤重金属剖面分布特征

Vertical Distribution of Heavy Metals in Five Types of Soils from Tea Plantations at Wuyishan

采用野外调查和室内分析相结合的方法,研究武夷山市5种类型茶园土壤（黄壤、红壤、潮砂土、高山草甸土、紫色土）重金属剖面分布特征。结果表明：茶园土壤Fe、Mn、Cu、Zn、Cd和Pb的含量范围分别为17.35~44.91 g·kg-1、144.81~693.55 mg·kg-1、4.36~57.12 mg·kg-1、74.92~236.27 mg·kg-1、0.09~0.67 mg·kg-1和22.71~91.87 mg·kg-1。不同类型茶园土壤重金属含量差异较大,茶园黄壤Fe和Cu含量显著高于其它土壤类型;潮砂土和高山草甸土茶园土壤Mn、Zn和Cd含量显著高于黄壤和红壤;茶园土壤Pb含量则以潮砂土最高,黄壤最低。不同重金属元素剖面分布规律略有不同,茶园土壤Fe含量0~80 cm深度内并无明显的变化规律;茶园土壤Mn、Cu和Zn含量在0~20 cm土层含量较高（潮砂土除外）;黄壤、红壤和紫色土Cd和Pb含量由上至下呈递减的趋势,潮砂土Cd和Pb在40 cm以下土层含量较高。相关分析表明,除了Zn与Fe和Cu以外,其它重金属之间存在显著或极显著相关性,表现为多种重金属复合污染;土壤有机碳、全氮、p H、砂砾、粉粒和粘粒对茶园土壤重金属影响较大。

From field surveys and laboratory analyses, the vertical distribution of heavy metals in 5 types of soils （i.e., yellow, red earth, moist sandy, alpine meadow and purple soils）of tea plantations at Wuyishan City was obtained. It was shown that in the soils the contents of feranged from 17.35 g·kg-1 to 44.91 g·kg-1, Mn from 144.81 mg·kg-1 to 693.55 mg·kg-1, Cu from 4.36 mg·kg-1 to 57.12 mg·kg-1, Zn from 74.92 mg·kg-1 to 236.27 mg·kg-1, Cd from 0.09 mg·kg-1 to 0.67 mg·kg-1, and Pb from 22.71 mg·kg-1 to 91.87 mg·kg-1. Disregardingthe variation on tillage, significant differences on heavy metals existed among the 5 soil types. Fe and Cu in the yellow soil were significantly higher than those in others. Mn, Zn and Cd in the moist sandy and the alpine meadow soils were significantly higher than those in either the yellow or the red earth soils. The alpine meadow soil contained the highest amount of Pb, and the yellow soil lowest, among all. The metal distribution in the soils varied by depth. For Fe, no significant difference was found in the depth of 0 to 80 cm of the soils. For Mn, Cu and Zn, with the exception of the moist sandy type, the highest metal contents were observed in the surface layer. In general, the contents of Cd and Pb decreased with the depth, but the highest contents of these metals were located 40 cm below the surface of the moist sandy soil. There were significant or extremely significant correlations among the heavy metals（except Zn, Fe and Cu）indicating compounded pollution at the plantations. In addition, it appeared that the organic matters, total N and pH, as well as the sand-, silt- and clay-type of the soils affected the heavy metal distribution as well.