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研究论文

Effect of simulated acid rain on chemical behavior of copper in paddy soils and plant of Taihu Lake region

摘要：以太湖地区两种典型的水稻土(乌泥土和白土)为供试土壤,在盆栽条件下种植多年生黑麦草,并配制不同pH值的模拟酸雨浇灌.通过多次刈割鲜草,研究模拟酸雨对土壤植物系统中铜的化学行为的影响.结果表明:对植物体内铜含量的影响是模拟酸雨和“稀释效应”两种影响综合作用的结果.试验初期,表现为处理黑麦草体内铜含量低于对照;随收割茬次的增加,表现出随处理pH的降低,黑麦草体内铜含量增加,且对缓冲能力弱的白土影响强度大于缓冲能力较强的乌泥土;对土壤pH有明显影响,随模拟酸雨作用时间增长,土壤pH下降,其降幅随处理pH的降低而

Abstract：Two typical paddy soils, bleached paddy soil and gleyed paddy soil, collected from Taihu Lake region were used to investigate the effect of acid rain on chemical behavior of copper in soils and plant by simulated and incubated approaches. Results indicated that simulated acid rain showed initially positive effect on ryegrass growth in terms of biomass. However, as the growth continued negative effect presented. The negative effect was often found in soils either with low buffer capacity such as bleached paddy soil,or treated with lower pH of the simulated rain. Measurement of Cu in ryegrass biomass indicated that biomass harvested in early growing stage contained less Cu than the control. However, as more times the ryegrass were harvested and the lower pH of acid rain was applied, Cu content in biomass tended to increase. This trend was once again more obvious in bleached paddy soil. These data suggested that Cu content in biomass was the net results of the combination of acidification effect and the plant dilution effect. Prolonged simulation of acid rain decreased soil pH, acidifying the soil environment, and mainly affected exchangeable Cu. Moderate acidity of acid rain (pH=3) affected carbonate associated Cu. It was only the very strong acidity of acid rain that changed the status of Fe/Mn associated Cu. Organic Cu and residue Cu were almost unchanged even though the acidity of the rain was very strong.