Soil biological recovery and plant growth under arbuscular mycorrizhal fungi inoculation in iron mining tailings and soil mixtures

ABSTRACT The deposition of iron mining tailings impairs soil quality and hinders its recovery. Arbuscular mycorrhizal fungi (AMF) associated with plants may enhance soil restructuring, biochemical processes, and functionality.3 This study aimed to evaluate plant growth and soil biological activity over two successive maize (Zea mays L.) cultivation cycles in substrates formed by mixtures of mining tailings and natural soil, and with AMF inoculation. Two greenhouse experiments were conducted using a completely randomized design. The first experiment had three treatments: natural soil, pure tailings, and a 1:1 soil-tailings. The second experiment evaluated the soil-tailings mixture under three conditions: untreated (reference, used as a control), autoclaved, and inoculated with an AMF spore mix. In both experiments, maize plants were grown for 45 days. Plant growth was measured, and soil and root samples were collected for biological and biochemical activity. In Experiment 1, the soil-tailings mixture and natural soil had similar glomalin levels and mycorrhizal colonization, but the mixture showed reduced plant development and enzymatic activity. In Experiment 2, AMF inoculation enhanced root colonization but did not improve enzymatic activity or glomalin content. The autoclaved treatment reduced plant growth but showed higher induced respiration. The findings indicate that successive cultivation cycles foster soil microbiota, primarily through the input of labile organic matter, which in turn improves plant performance and supports soil recovery in tailings-impacted environments.