土壤外源铜形态的动态变化:5年定位试验  

Dynamic Variations of Distribution Forms of Exogenous Copper in Soil:A 5-Years Located Experiment

作　　者：赵江宁[1] 王云霞[1] 沈春晓[1,2] 杨连新[1] 王余龙[1] 

机构地区：[1]扬州大学江苏省作物遗传生理重点实验室,江苏扬州225009 [2]光明种业有限公司,上海崇明202150

出　　处：《农业环境科学学报》2012年第5期926-933,共8页Journal of Agro-Environment Science

基　　金：江苏省科学技术厅社会发展计划(BS2006019);江苏省"333 高层次人才培养工程"项目(2009);江苏省"六大人才高峰"项目(07-G-023);江苏高校优势学科建设工程资助项目

摘　　要：土壤铜污染的危害性不仅取决于总量,还与其在土壤中的形态有关。选用未受污染的粘质壤土,设置对照(32mg·kg-1)、200、400mg·kg-1铜处理模拟土壤铜污染,进行持续5年(2006—2010年)的稻/麦轮作土培试验。参照Tessier的方法测定小麦和水稻成熟期土壤中不同形态铜含量,研究耕作层土壤中各种形态铜含量的动态变化。结果表明:(1)试验期内清洁土壤中总铜以及可交换态、碳酸盐结合态、铁锰氧化物结合态、有机物结合态、残渣态铜含量变化均很小,铜处理使上述参数均大幅增加。(2)污染土壤各形态铜含量随时间推移而变化,其中可交换态浓度持续下降最为显著,5年分别累计下降66%(200mg·kg-1)、67%(400mg·kg-1)。(3)土壤处于旱作条件有利于碳酸盐结合态和有机物结合态铜向铁锰氧化物结合态转化,淹水条件下转化方向相反。(4)铜处理改变了土壤中铜元素的形态分布,清洁土壤主要以残渣态存在(平均占57%),污染土壤中碳酸盐结合态和铁锰氧化物结合态铜所占的比例明显增加(合计平均占58%)。本研究表明,外源铜进入土壤后,易被植物吸收利用的可交换态浓度持续大幅降低,其他形态则因不同年度和不同耕作方式而相互转化。Copper（ Cu ） is an essential micronutrient for crops meanwhile it is also a heavy metal when soil Cu availability exceeds plant＇s normal requirement. Tbe risk of soil copper contamination was related to total Cu concentration and different forms of Cu in soil. In order to investigate the dynamic changes of Cu added into soil, a 5-years experiment （2006-2010） was conducted using cement-tank to avoid Cu leaching into local soil. A clay loam soil was treated with 3 different Cu levels （CK 32 mgkg-1; 200 mg.kg-1 and 400 mgkg-1）. A rice-wheat rotation cropping system was adopted in this long-term experiment. After each halwest of wheat or rice, the soils were analysed by using the method of Tessier 5-continuous extraction. Results showed that： （ 1 ）During whole experiment period of 5 years, tt,e clean soil did not show nmch variation in the concentrations of total Cu and it＇s 5 fractions ： changeable, bound to carbonates, bound to Fe-Mn oxide, bound to organic matter and residual Cu, but in polluted soil these parameters increased largely; （2）Cu concentration of different fonas in polluted soil changed with time, especially the exchangeable Cu decreased 66% and 67% for Cu treatments of 200 mg .kg and 400 mg·kg-1 in 5 years, respectively;（3 ）Cu bound to carbonates and organic matter could transform to Fe-Mn oxide-bound Cu under dry conditions, but in re- verse under wet conditions; （4）Cu treatments also changed the distribution of difterent Cu forms in soil the majority of Cu in clean soil was residual Cu （57%）, while in polluted soil the percentage of Cu bound to carbonates and Fe-Mn oxide increased to 58% in total. This study indicated that after Cu entered into soil, the exchangeable-Cu which plant could uptake and utilize readily decreased significantly, which implies that Cu toxicity to plants can he greatly reduced by time.

关 键 词：土壤 铜 赋存形态 定位试验 

分 类 号：X53[环境科学与工程—环境工程]