镉污染稻草还田对土壤镉形态转化的影响  

Effects of Cd-contaminated Rice Straw Incorporation on Transformation of Cd Forms in Soils

作　　者：曹晓玲[1,2] 罗尊长[2] 黄道友[1] 朱奇宏[1] 刘守龙[1] 饶中秀[1] 任雪菲[1] 席园[1] 

机构地区：[1]中国科学院亚热带农业生态研究所,亚热带农业生态过程重点实验室,长沙410125 [2]湖南省土壤肥料研究所,长沙410125

出　　处：《农业环境科学学报》2013年第9期1786-1792,共7页Journal of Agro-Environment Science

基　　金：国家科技支撑计划项目(2012BAD05B06;2012BAJ24B03);湖南省科技重大专项(2011FJ1002-3)

摘　　要：采用模拟培养实验，研究了镉污染稻草还田后清洁土壤（pH=4．72）和镉污染土壤（pH=7．90）中有效态镉含量及镉形态分布的变化特征。结果表明：添加稻草和淹水培养使土壤pH值向6．0—7．5的区间转变，并显著提高了土壤可溶性有机碳（DOC）含量。清洁土壤添加镉污染稻草后，土壤DTPA（Diethylene triamine pentacetate acid）提取态cd含量增加23．5％-225．0％，土壤酸提取态和可还原态镉的相对比例显著提高，而残渣态和可氧化态镉的比例则相对降低，其效果随稻草添加量的增加显著增强；镉污染土壤添加镉污染稻草后，DTPA提取态镉仅在培养初期（2d）略有提高，随培养时间的延长，DTPA提取态镉含量显著降低（28．6％～41．1％），且添加稻草促使酸提取态镉向可还原态镉和残渣态镉转化。研究表明，镉污染稻草进入清洁土壤会带来镉污染的扩散风险，而进入供试污染土壤后则能在一定程度上降低污染土壤中镉的有效性。To investigate the effects of Cd-contaminated rice straw incorporation on the Cd fractions and the available Cd contents in soils（a non-contaminated soil, pH=4.72 gnd a Cd-contaminated soil, pH=7.90） an incubation experiment（28 d） was conducted. The results indi- cated that after the addition of rice straw（both contaminated and clean rice straw） the pH in both soils were neutralized（6.0 to 7.5 ） and the contents of dissolved organic carbon（ DOC ） in both soils were sharply increased in the first 2 d and reduced gradually in the rest incubation period. At the same time, Cd-contaminated rice straw incorporation significantly increased the DTPA extractable Cd by 23.5%~225.0% and the proportions of acid-extractable and reducible Cd, and relatively decreased the proportions of residual and oxidizable Cd in clean soil. These effects were enhanced with the increasing of Cd-contaminated rice straw added. Whereas, in Cd-contaminated soil, the DTPA ex- tractable Cd was slightly increased firstly, and then decreased（by 28.6%~41.1% ） continually during the rest incubation period（2~28 d） when Cd-contaminated rice straw was applied. Moreover, the addition of Cd-contaminated rice straw reduced acid-extractable Cd and si- multaneously increased reducible Cd and residual Cd in Cd-contaminated soil. In conclusion, the application of Cd-contaminated rice straw may induce Cd-pollution risk in clean acidic soil and contrarily may reduce the availability of Cd in Cd-contaminated alkaline soil.

关 键 词：稻草还田 CD污染 清洁土壤 污染土壤 土壤Cd形态 

分 类 号：X53[环境科学与工程—环境工程]