中文关键词农地土壤铅(Pb)镉(Cd)有效性黑麦草 英文关键词farmland soilleadcadmiumavailabilityLolium perenne L.

作者	单位	E-mail
陈莹	西南大学资源环境学院, 重庆 400715 重庆市农业资源与环境研究重点实验室, 重庆 400715	479076414@qq.com
刘汉燚	西南大学资源环境学院, 重庆 400715 重庆市农业资源与环境研究重点实验室, 重庆 400715
刘娜	西南大学资源环境学院, 重庆 400715 重庆市农业资源与环境研究重点实验室, 重庆 400715
蒋珍茂	西南大学资源环境学院, 重庆 400715 重庆市农业资源与环境研究重点实验室, 重庆 400715
魏世强	西南大学资源环境学院, 重庆 400715 重庆市农业资源与环境研究重点实验室, 重庆 400715	sqwei@swu.edu.cn

中文摘要 作物重金属累积主要受土壤中重金属有效性的制约，由于土壤种类和污染特征的差异，目前尚无公认的有效态测定方法.为筛选建立适宜土壤铅（Pb）和镉（Cd）有效性评价的方法，本文选择重庆市4种性质差异较大的典型农地土壤：酸性紫色土、中性紫色土、石灰性黄壤和钙质紫色土，系统比较了氯化钙（CaCl₂）、醋酸铵（NH₄OAc）、盐酸（HCl）、乙二胺四乙酸二钠盐（EDTA）和二乙基三胺五乙酸（DTPA）这5种化学提取方法与梯度扩散薄膜技术（DGT）对供试土壤Pb和Cd的提取能力，并以黑麦草为指示植物开展盆栽试验，探讨不同提取剂提取量与植物Pb和Cd累积能力的相关性，进而综合评价不同方法的适宜性.结果表明，不同提取方法对Pb和Cd的提取量存在明显差异：酸性紫色土和石灰性黄壤中以HCl-Pb提取态含量最高，中性紫色土和钙质紫色土中则以EDTA-Pb提取态含量最高；除钙质紫色土以EDTA-Cd提取态含量最高外，其余3种土壤则是以HCl-Cd提取态含量最高.考虑提取量与植物吸收量之间的相关关系，在相同类型土壤上，可选择除CaCl₂外的5种提取方法作为Pb的评价方法，Cd则是6种提取方法均较适合.在不同类型土壤中，EDTA-Pb提取态和DGT-Cd提取态含量与黑麦草地上部Pb和Cd含量相关性最高，相关系数分别为0.941和0.919，说明EDTA提取适用于不同类型土壤间Pb生物有效性的比较与评价，而Cd则以DGT技术最好，化学提取剂中以HCl较为适宜. 英文摘要 The accumulation of heavy metals in crops is largely dependent on the availability of heavy metals in soils. Due to the differences of soil types and pollution characteristics, there is no widely recognized method for the determination of the bio-available heavy metals in soils such as Pb and Cd. In order to screen and establish suitable methods, the extractable abilities of five extractants (CaCl₂, NH₄OAc, HCl, EDTA, and DTPA) and Gradient Diffusion Film Technology (DGT) on four typical farmland soils with very different properties in Chongqing (acid purple soil, neutral purple soil, calcareous yellow soil and calcareous purple soil) were systematically compared. Simultaneously, pot experiments were carried out with Lolium perenne L. as an indicator plant to explore the relationship between the extractable soil Pb and Cd and their accumulation in plants. The feasibility of the tested methods were evaluated based on the extractability and co-relationships. The results showed that the extractability of the tested extractants for soil Pb and Cd varied a lot. HCl showed highest extractability on Pb in acid purple soil and calcareous yellow soil, while EDTA did the best in neutral purple soil and calcareous purple soil; HCl showed best extractability in all soils except calcareous purple soil, where EDTA was the best. Considering the correlation between the extraction amount and uptake by plant, all the extraction methods could be applied for the evaluation of the bioavailability of soils Pb and Cd except CaCl₂ for Pb due to its weak extractability for Pb for a specific soil type. For the comparison of heavy bioavailability in different soil types, EDTA-extractable Pb and DGT-extractable Cd were recommended due to their well co-relationships between extractable amount in soil and uptake by plant (Lolium perenne L.) as indicated by the correlation coefficients of 0.941 and 0.919, respectively. HCl was relatively suitable as Cd extractant compared to others if DGT method could not be used.

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