| 摘要: |
| [目的]研究黄土高原主要农田土壤重金属Cd的形态与生物有效性的关系,为评价本区土壤重金属Cd污染程度及其生物有效性提供一定的理论与数据依据.[方法]以黄土高原自北向南采集的12个0～20 cm耕层土壤为供试土样,通过室内分析和盆栽试验,研究了黄土高原石灰性土壤中不同形态Cd的分布特征及其生物有效性.[结果]黄土高原农田土壤Cd各形态总体分布特征为:有机结合态Cd、铁锰氧化物结合态Cd＞碳酸盐结合态Cd＞交换态Cd＞残渣态Cd,自北向南各形态Cd含量均呈不同程度的增加趋势.各土壤类型间铁锰氧化物结合态Cd及碳酸盐结合态Cd平均含量均表现为;干润砂质新成土＜黄土正常新成土＜简育干润均腐土＜土垫旱耕人为土,自北向南依次增加.碳酸盐结合态Cd和全Cd含量主要受到全氮、有效磷和砂粒含量的影响,且全氮和有效磷含量对其的影响为正效应.铁锰氧化物结合态Cd含量主要受全氮、有效磷、砂粒和粉砂粒含量的影响,且全氮、有效磷和粉砂粒含量对其的影响为正效应.土壤中各形态Cd含量与有机质、C/N、pH、CaCO3、粘粒含量的相关性均不显著,其中与C/N、pH、粘粒含量呈负相关.Cd在小麦茎叶层的含量小于根系;而作物不同部位Cd累积量表现为茎叶＞根系.[结论]相关分析表明,小麦茎叶Cd累积量与土壤中各形态Cd及全Cd含量无显著相关性,而根系Cd累积量和小麦Cd累积总量与土壤铁锰氧化物结合态Cd及全Cd含量呈显著正相关,说明黄土高原主要农田土壤中铁锰氧化物结合态Cd具有较高的生物有效性. |
| 关键词: 黄土高原 Cd形态 生物有效性 小麦 |
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| 基金项目:国家自然科学基金项目（90502006）；西北农林科技大学创新团队项目 |
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| Study of soil Cd fractionation and its bioavailability on the Loess Plateau |
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| Abstract: |
| 【Objective】 The problem of heavy metal pollution is becoming more and more serious. But the indicators of soil pollution are not perfect.The research was on the relationship of heavy metal Cd fractionation and its bioavailability on the Loess Plateau,which could be used to assess soil Cd pollution and its bioavailability,and provided a basis for theory and data in the region. 【Method】 12 soil samples of the 0-20 cm layer were collected from north to south on the Loess Plateau,both the soil Cadmium fractionation and its bioavailability were studied by using laboratory analysis and pot experiment. 【Result】 The results indicated that different fractionations of Cd in soil distributed in an order of succession:bound to organic matter＞bound to Fe-Mn oxide＞bound to carbonate＞exchangeable＞residue,the different forms of Cd increased from north to south on the Loess Plateau,and the average Cd contents of exchangeable and bound to carbonate fractionation were:Ust Sandic Entisols
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| Key words: the Loess Plateau Cadmium form bioavailability wheat |
