土壤中铁锰的形态分布及其有效性研究

以乌鲁木齐雅马里克山的土壤为研究对象,采用Tessier连续提取法对土壤铁、锰各种化学形态进行浸提.研究了土壤中有效铁、锰和土壤的理化性质与土壤铁、锰形态之间的关系,及对铁、锰在土壤中存在形态的影响;并通过盆栽试验对铁、锰的植物有效性进行了分析.结果表明,土壤铁主要以残渣态为主,占全铁的92.3%,其它形态含量均小于全量的8%.土壤锰主要是以铁锰氧化态和残渣态为主,分别占全锰的49%和41.6%,其它形态含量均小于全量的10%.用二级出水灌溉处理可增加铁、锰的有效性,原污水灌溉不利于铁、锰的供应,土壤缺铁、锰的现象可通过施加一定量的铁盐和锰盐而得以改善.相关分析还表明,土壤的理化性质与铁锰形态之间有一定的相关性.供试土壤的pH值、CaCO3含量、有机质及阳离子交换态等对土壤铁、锰的有效性影响较大.逐步回归分析表明,铁的氧化物结合态对植物最为有效,锰的有机结合态对植物有效性贡献最大.

Soil iron-and manganese forms and their availability to plants

Soil samples were collected from Yama Mountain area in Urumqi, and Tessier sequential extraction procedure was used to extract different chemical forms of soil Fe and Mn. Pot experiments were conducted to investigate the relationships of soil Fe and Mn forms with soil physical chemical proprieties, and their availability to plants. The results showed that soil Fe was dominated by residual form, which accounted for 92.3 % of soll total Fe. The proportion of other Fe forms was less than 8%. Soil Mn was dominated by Fe and Mn oxidesbound and residual forms, and their contents were 49 % and 41.6 % of total Mn, respectively. The proportion of other Mn forms was less than 10%. Irrigation with secondary effluent increased the availability of Fe and Mn, but irrigation with untreated wastewater was not profitable to Fe and Mn supply. The deficiency of soil Fe and Mn could be improved by adding Fe and Mn salts. Correlation analysis showed that there was certain relativity between soil physicallchemical proprieties and soil Fe and Mn forms. Soll pH, CaCO3, organic matter, and exchangeable cations had significant effects on the availability of Fe and Mn. Stepwise regression analysis showed that Fe-Mn oxides-bound Fe was most available to plant Fe nutrition, whereas organic matterbound Mn contributed to the largest share in plant Mn availability.