湖南洞庭湖地区土壤-作物系统铅含量及其影响因素
Pb content in the soil-crop system in the Dongting Lake region, Hunan, China, and its influence factors
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摘要: 以湖南洞庭湖地区为研究区域，探讨了土壤有机质、PH值、P、N对Pb在土壤-作物系统中迁移的影响，研究了Pb、Cd复合污染对水稻Pb、Cd富集的作用。相关分析结果表明：随土壤有机质含量的增加，离子交换态Pb含量减少，但通过转化可以被植物吸收利用的有机质的结合态Pb含量增加，进而增加了水稻对土壤Pb的吸收量；土壤为中性偏碱性时，土壤中Pb的活性和水稻Pb的富集能力均较酸性土壤中有所降低；在土壤中增施氮肥和磷肥可降低土壤中离子交换态Pb的含量，减少水稻对Pb的吸收。因此，土壤有机质、PH值、P、N是影响水稻Pb含量及土壤Pb活性的重要因素。Pb—Cd复合污染研究结果表明：土壤中同时存在Pb、Cd时，Pb元素的存在促进了水稻对Cd元素的吸收，而Cd却抑制了水稻对Pb的吸收。Abstract: The authors studied the influence of organic matter,pH values,P and N in soils on Pb migration in the soil-crop system as well the influence of compound pollution of Cd and Pb on the concentration of Pb and Ca in rice in the Dongting Lake region,Hunan.The results of correlation analysis indicates that:the content of ion-exchangeable Pb in soils decreases somewhat with increasing organic matter,but the content of organic bound-state Pb,which can be absorbed by plants,increases through conversion,and thus the capacity of absorption of Pb in soils by rice increases;when the soils are neutral-subalkaline,the bioactivity of Pb in soils and Pb concentration factor(CF) in rice are both lower than those in acid soils;when nitrogenous and phosphate fertilizers are applied to the soils,the ion exchangeable Pb in soils can be reduced and so can the capacity of absorption of Pb by rice.Therefore organic matter,pH values,P and N in soils are important factors influencing the Pb content in rice and Pb bioactivity in soils.The study of compound pollution of Cd and Pb shows that the presence of Pb in soils may promote the absorption of Cd by rice,whereas the presence of Cd inhibits the absorption of Pb by rice.
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Keywords:
- Hunan /
- soil-crop system /
- Pb /
- influence factor /
- interaction
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