湖南酸性水稻土有效镉提取剂的研究

Extractants for Available Cadmium in Acid Paddy Soils in Hunan

为筛选酸性水稻土有效镉最佳提取剂,在湖南湘东地区共采集了36个5种类型母质水稻土耕层样品和对应23个早稻植株和稻谷样品,采用DTPA、NH4OAc、CaCl_2、MgCl_2 4种提取剂提取土壤有效镉,结合精米和稻秆中的镉含量分析比较了4种提取剂效果。结果表明:在酸性水稻土中(pH值4.78~5.73),4种提取剂提取率为DTPA>MgCl_2>CaCl_2>NH4OAc,精米中镉含量均与土壤有效镉含量呈显著正相关关系,综合比较以MgCl_2提取剂效果最好,通过回归方程预测精米镉含量低于国家标准0.2 mg/kg时土壤中MgCl_2可提取的镉量应≤0.092 mg/kg。

In order to select the effective cadmium extract of acid paddy soil,.36 paddy soil samples and 23 rice plant samples were collected from Changsha, Xiangtan, Zhuzhou in Hunan Province. Four kinds of extractants, DTPA, NH4 OAc, CaCl2, MgCl2 were used to extract available Cd in these soil, then analyzed the extraction ability by compared these available Cd content with the content of Cd in rice and straw. The results showed that in the acid paddy soil（p H value of 4.78-5.73）, the extraction rate of 4 extracts was DTPA 〉MgCl2 〉CaCl2〉 NH4 OAc, and there were extremely significant correlations between the Cd content of rice and the Cd content of soil. Through comprehensive comparison, it was found that MgCl2 was the best extractant. By regression equation prediction, it turns out that to make sure the Cd content of rice lower than 0.2 mg/kg, the Cd content extracted by MgCl2 should less than 0.092 mg/kg.