通过室内土壤培养试验,研究单独添加赤泥或堆肥以及两种添加物一起添加对土壤锌形态转化的影响。结果表明,单独添加赤泥或堆肥均可以降低土壤中交换态-Zn的比例,提高铁锰氧化物结合态-Zn和有机结合态-Zn的比例。与对照相比,添加5%赤泥,培养1个月后土壤中交换态-Zn在Zn形态中的比重由51%下降到0%;铁锰氧化物结合态-Zn和有机结合态-Zn的比重由31%和7%分别提高到66%和13%。说明赤泥和堆肥均可以固定土壤中的Zn,降低Zn的植物有效性。试验还表明,赤泥和堆肥一起应用到污染土壤中,其固定土壤Zn的效果比单独添加堆肥时好。
An indoor soil column cultivation experiment was carried out to investigate the effects of compost and red mud on the transformation of zinc (Zn) speciation. After adding 5% (by weight) red mud, 10% (by weight) compost, and 5% red mud and 10% compost together, the soil columns were cultivated for 3 months in 9 replicates. We kept water in soil to maintain 60% of field holding capacity at room temperature (25 ℃). Three replicates were sampled each month, and speciation of Zn was measured using a sequential extraction method. We found that individual amendment of red mud or compost into soil could both reduce the percentage of exchangeable-Zn, and increase the proportion of organic and Fe-Mn oxide fractions. When compared with the control, 5% RM (red mud) amendment could significantly reduce the exchangeable Zn fraction in soil from 51% to 0% after one month cuhivation. However, the Fe-Mn oxide and organic fractions were significantly increased from 31% and 7% to 66% and 13%, respectively. This phenomenon was maintained for 3 months. Our results showed that both red mud and compost could immobilize the Zn in soil, reducing its bioavailability. We also found that the red mud and compost when applied together enhanced the immobilization of Zn more effectively than single compost amendment.