BIOCHEMICAL ATTRIBUTES AND ESTABLISHMENT OF TREE SEEDLINGS IN SOIL AFTER DEPOSITION OF IRON MINING RESIDUES

The recovery of areas impacted by mining activities is a major challenge and requires knowledge of how the biological and biochemical processes of the soil as well as the establishment of plant species are affected by mining residue. In this work, the influence of deposition of iron mining mud and tailings on soil biochemical attributes and the initial development of tree seedlings was studied in a simulated event in the greenhouse. Pots (n = 27) with natural soil (2.0 kg) received deposition (280 mL) of iron mining mud or tailings and by three-month was cultivated with Urochloa decumbens. At the end of this period, part of the pots was sampled and the soil biochemical activities (basal soil respiration, microbial biomass carbon, enzyme activity β-glucosidase, quantification of easily extractable glomalin) were evaluated. Then tree seedlings (Schinus terebinthifolius and Eremanthus incanus) were planted and cultivated for a year, when then shoot (SDW) and roots (RDW) dry weight were evaluated. The mud deposition reduced (p < 0.05) the SDM of E. incanus. The deposition of iron mining mud and tailings affected negatively (p < 0.05) the β-glucosidase and reduced in 19% the easily extractable glomalin. Nevertheless, Uruchloa decumbens and Eremanthus incanus showed no variation in dry weight production between treatments, showing good establishment capacity in soil affected by mining residue.