Inoculum potential of arbuscular mycorrhizal fungi in iron ore tailings areas under rehabilitation

ABSTRACT Mining has long been important for Brazil’s economy, but it causes severe environmental damages. The Fundão Dam disaster in Minas Gerais, for example, harmed ecosystems and soil biota, particularly arbuscular mycorrhizal fungi (AMF). These fungi are essential for soil and plant health, but mining reduces their colonization. Revegetation with proper management and AMF inoculation can accelerate ecological recovery. This study evaluated the inoculum potential of AMF in mining-impacted areas at different revegetation stages in Mariana, Minas Gerais. Soil samples were collected for chemical analyses, spore and mycorrhizal colonization quantification, and soil inoculum-efficiency tests. Our results showed that areas with five years of revegetation had higher spore viability and colonization, indicating the onset of ecological stabilization. However, these levels remained lower than those observed in the reference area. Longer revegetation periods increased colonization and symbiotic efficiency. Overall, revegetation contributed to the chemical and microbiological recovery of soils, but full recovery of mycorrhizal function requires more time and more favorable environmental conditions.