Condicionadores químicos e inoculantes microbiológicos no crescimento da Urochloa brizantha sobre rejeito da barragem de Fundão, Mariana, MG

Abstract

The Quadrilátero Ferrífero, located in the state of MG, is the region with the largest production of Fe ore in Brazil, and promotes great socioeconomic development for the country. Despite this essentiality, the mining process is an activity that causes degradation in ecosystems. Following the breach of the Fundão dam in 2015, in the district of Mariana-MG, which released approximately 34 million m3, techniques are needed to assist in the revegetation process for the rehabilitation of the area. However, the application of soil conditioners can help improve tailing conditions for plant development, just as the interaction between soil microbiota can benefit the establishment of plants on site. Therefore, the aim of this study was to evaluate how soil conditioners affect the chemical conditions of tailings and Urochloabrizantha development and to evaluate the contribution of AMFs to soil microbial activation in tailings and growth of Urochloabrizantha in Fe mining tailings. Mining tailings samples from Fe from Mariana were collected to cultivate Urochloabrizantha with different soil conditioners and in another stage with mycorrhizal fungi associated with different concentrations of microbial cells.The first study was carried out in a greenhouse with seven treatments (control and six different soil conditioners biochar, charcoal, manure, organic compost, plaster and sulfur) and five replicates. content and accumulation of elements in plants. The second study was conducted in a greenhouse and consisted of a 5 x 2 factorial, with five dilutions for extinction of soil microorganisms (0, 10-1, 10-3, 10-6 and 10-9) with and without inoculation. with FMAs, in four repetitions. Quantification of micrometer colonization, fluorescence diacetate hydrolysis activity, microbial biomass carbon determination, spore extraction and easily extractable glomalin and total mycelium length were evaluated.The application of gypsum and sulfur provided the largest SDM, RDM and increase in the accumulation of chemical elements in relation to the other conditioners, however, were similar to the control, which indicates that the technosol has no negative effect on plant growth. Application of coal and organic compost and manure provided increases in pH. The conditioners used were not efficient in altering the physicochemical characteristics of the Technosol and in promoting the growth of Urochloabrizantha.Already mycorrhizal fungi arbitrate to favor the increase of soil microbial biomass, but were not able to promote the growth ofUrochloabrizantha. The tailings show no restriction on the growth of UrochloaBrizantha, but it does not provide favorable conditions for the development of an appropriate microbiota for the restoration of ecosystem services at sites affected by the dam rupture.