Instituto Tecnológico Vale, R. Boaventura da Silva 955, Nazaré, Belem, PA, 66055-090, Brazil.
Instituto de Ciências Agrárias, Universidade Federal Rural da Amazônia, CP 917, Belem, PA, 66077-530, Brazil.
Environ Monit Assess. 2020 May 24;192(6):390. doi: 10.1007/s10661-020-08365-4.
Impacted areas by iron mining may face challenges in the management of phosphate fertilization and reduced efficiency of rehabilitation practices, thus extending the time required for the rehabilitation of these areas. The objective of this study was to evaluate phosphorus (P) lability in soils of native forest and ferriferous canga areas (savanna vegetation above ironstone outcrops covering iron ore deposits) and in iron mine waste piles undergoing rehabilitation. Benches of the analysed waste pile differ in age of rehabilitation: as the initial rehabilitation stage (INI), we consider benches with fewer than 3 years of rehabilitation; the intermediate stage (INT) were benches with up to 5 years of rehabilitation; and the advanced rehabilitation stage (ADV) corresponds to benches with more than 8 years of rehabilitation activities. Organic and inorganic P fractions were analysed in these areas by chemical fractionation and were classified according to the degree of soil lability. The results show that in the canga environment, there was a predominance of inorganic fractions of moderate lability and moderate stability, with a strong dependency of the soil organic matter (SOM) on the P fractions, whereas there was a greater participation of the moderately labile organic fractions in the forest than in the canga. On the other hand, in the rehabilitation areas, there was an increase in the labile organic and inorganic fractions as the rehabilitation process advanced. The distribution of P in areas undergoing rehabilitation indicates that there is a tendency for P levels to resemble those of native environments, such as the forests.
受铁矿开采影响的地区可能在磷施肥管理和修复实践效率降低方面面临挑战，从而延长这些地区的修复时间。本研究的目的是评估原生林和含铁砾岩层（覆盖铁矿石矿床的铁石露头上方的热带稀树草原植被）以及正在进行修复的铁矿废石堆中的土壤中磷的可动性。分析的废石堆的长凳在修复年龄上有所不同：在初始修复阶段（INI），我们考虑修复不到 3 年的长凳；中期修复阶段（INT）是指修复时间长达 5 年的长凳；高级修复阶段（ADV）则对应于修复活动超过 8 年的长凳。通过化学分级，在这些地区分析了有机和无机磷分数，并根据土壤的可动性程度进行了分类。结果表明，在铁砾岩层环境中，存在中等可动性和中等稳定性的无机磷分数占主导地位，土壤有机质（SOM）对磷分数有很强的依赖性，而在森林中，中等可动性有机磷分数的参与度大于铁砾岩层。另一方面，在修复区，随着修复过程的推进，可动有机和无机磷分数增加。正在进行修复的地区的磷分布表明，磷水平有趋于类似于原生环境（如森林）的趋势。
