有机肥对铅在土壤中形态分配的影响

Effects of organic manure on Pb speciation in soil

为了解铅污染商品有机肥对培养土壤中铅形态的影响以及低铅含量有机肥对外源铅污染土壤中铅形态分配的影响,在海南采集了4种商品有机肥样品,进行有机肥与土壤铅污染的老化培养实验.结果表明,原土壤中重金属铅主要以交换态(33.43%)和残渣态(30.03%)存在,随着海藻有机肥(HK01)和羊粪有机肥(DF01)施肥量的增加,处理土壤中交换态铅的比例显著降低(P<0.05),有机结合态从9.56%提高到22.05%.外源铅(250 mg·kg-1)污染土壤中以交换态(36.21%)、铁锰态(27.03%)和碳酸盐结合态铅(23.54%)为主;随着有机肥料添加量的增大,格瑞龙有机肥处理后,污染土壤中的交换态铅的比例有所下降,添加量为10%时比例最低为27.80%;有机结合态和残渣态铅的比例上升,在20%时比例最大为13.68%、13.35%.鱼蛋白豆粕有机肥处理的土壤中交换态铅和碳酸盐结合态铅比例下降,在添加量为20%时比例分别降低到11.75%和11.89%,铁锰氧化物结合态铅变化不显著;铅主要转入有机结合态铅和残渣态,平均增长比例分别为8.42%、3.03%.施用有机肥经过足够长时间的老化均会使土壤中的有效性高的铅转化成稳定态的铅,因此有机肥对铅污染的土壤的修复作用较大.但是由于重金属铅的移动性差,会累积在土壤表层,施用有机肥前还是要经过检测,选用相对安全的有机肥改良土壤.

Four types of commercial organic manures collected from Hainan Province were used in the incubation experiment of organic manure with lead contaminated soil in order to investigate the effects of commercial organic manures on lead（ Pb） speciation in high and low concentration Pb contaminated soil. Results show that the major lead fractions in the original control soil were exchangeable fraction（ 33.43%） and residual fraction（ 30.03%）. The exchangeable fraction of lead in high concentration Pb contaminated soils was significantly decreased with the increasing amount of algae organic manure（ HK01） and sheep-manure（ DF01）,while the organic matter bound lead was increased from 9.56% to 22.05%. The main lead fractions in soils contaminated at 250 mg·kg-1 Pb were exchangeable fraction（ 36.21%）,Fe-Mn oxides bound pool（ 27.03%） and carbonates boundpool（ 23.54%）.With increased contents of BT06 and BT03,the exchangeable fraction of Pb in the contaminated soil was reduced,and reduced the lowest rate（ 27.8%） when treated with 10% BT06.Proportions of organic bound and residual lead increased and were the highest（ 13.66%,13.35%,respectively） at 20%. Exchangeable and carbonate bound fractions of Pb treated by 20% BT03 were decreased by 11. 75%,11. 89%,respectively while the ratio of Fe-Mn oxides bound lead did not change significantly（ P〈0.05）. Lead forms in soil were mainly organic bound and residual fractions at average growth rates of 8.42%,3.03%,respectively. Available Pb in soil transformed into stable phases. Therefore,organic fertilizer had a greater effect on the remediation of contaminated soil after a long period of aging.