Comportamento de espécies vegetais em substrato de leucofilito para recuperação de área degradada pela mineração de argila

The mining is an important activity that promotes environmental impacts. The suppression of vegetation cover, changes in geomorphology and local pedology, water and atmospheric pollution and interactions with fauna are frequently recorded. Mines finalized, as in the areas degraded by the exploitation of clays and leucophylite ore (white phyllite) in the municipality of Bambuí-MG, present irregular pitches or benches, exhibiting sterile horizons of the soil, which are marked by its great hardness, low permeability, high concentrations of phytotoxics, what makes impossible the spontaneous resurgence of vegetal cover. This paper sought for the development of a technic of revegetation for the present degraded area in a greenhouse experiment, aiming to value the growth of species in its interactions with various substrates for identification of the most viable relationship to be used in vegetal recomposition of areas degraded by the mining of leucophylite. Four species were selected for the experiment (Acacia- Acacia mangium, Jambolão- Syzygium cumini, Pau-pombo- Tapirira guianensis and Vetiver grass- Chrysopogon zizanioides). Containers (25dm³) were prepared with different proportions of soil (topsoil of the mined area), phyllite ore, hidrogel and fertilizers, namely (S1: phyllite 100%, S2: phyllite and topsoil from the mined area in the proportion of 50%, S3: phyllite with topsoil from the mined area in the proportion of 50% and 100g of NPK 4-14-8 and added 2g of ammonium sulfate in the ninetieth day, S4 : 100% topsoil from the area). The experiment was conducted in the greenhouse of IFMG’s Biotechnology Laboratory (LABIOTEC), organized in Completely Randomized Designs with sixteen treatments, four blocks and duplicated plots aiming the minimization of losses of complete plots, totalizing 128 containers. The growth of the species was accompanied, recorded, and quantified aiming to find the best relation between specie and substrate for revegetation and recovery of the mined area. The analysis of the results pointed out the difficulties for the recuperation of the area, taking into account the physical and chemical characteristics of the substract in the mined area. Positives results were recorded in the response of Vetiver grass in the relation of this specie with the fertilized substract, witch presented the best growth in the root system, leaf material and the best results of N and K in the leaf material. For the Jambolão, were verified the biggest growth of the stalk diameter and the biggest growth of root amongst the arboreal species tested. The Acácia stood out for present characteristics of nodulation, notably in its interaction with the fertilized substract, with bigger concentration of N in the root. Pau- pombo presented the worst response for the treatments. From the technical point of view, the response of the interactions between plants and substract presented in this work can be useful to guide the vegetal recomposition of mining areas similar to those areas of clay and phyllite exploitation.