淹水条件下有机肥对土壤重金属形态转化及迁移的影响

采用土柱模拟试验，利用欧共体参比司提出的BCR连续提取法，探讨了重金属Zn，Cu，Pb，Cd在农田土壤中的化学形态及迁移风险。结果表明，施用不同有机肥对重金属向下迁移影响不大，淹水9个月后，Zn，Cu，Pb，Cd从表层土壤（0-20 cm）向下迁移了约2 cm，集中于20-22 cm土层，不易对深层土壤造成污染。添加有机肥后，0-10 cm土层中Zn，Cu，Pb，Cd的酸溶态比例随着淹水时间的增加而降低，而可还原态比例却随之升高，表明有机肥对重金属的有效性有一定的抑制作用。在此期间，可氧化态和残渣态的含量基本保持不变，两者百分比之和在各元素中均小于15%。

Effects of organic fertilizers on transformation and migration of soil heavy metals under flooded condition

A soil column experiment and BCR sequential extraction were applied together to investigate the chemical forms and migration risk of zinc （Zn）， copper （Cu）， lead （Pb） and cadmium （Cd） in the farm land soil. It was shown that application of different organic fertilizers had minimal effect on migration of heavy metals. After 9 months flooding， Zn， Cu， Pb and Cd migrated from the topsoil （0-20 cm） down about 2 cm （focusing on 20-22 cm soil layer）， which indicated limited pollution to the deep soil layers. After adding organic fertilizers， with the increase of flooded time， the percentage of acid\|extractable fraction decreased， while the reducible fraction increased， which indicated that organic fertilizers had certain inhibition effect on availability of heavy metals. The content of oxidizable and residual fraction remained substantially constant during this process， and the total percentage of oxidizable and residual fraction was less than 15%.