Influence of elementary added sulfur on a mining waste for nutrient release in soil

In the state of Paraíba and in Brazil, the exploitation of the vermiculite mineral has generated a large volume of waste in the vicinity of the mining companies, which has become a significant environmental liability, with polluting or contaminating potential. Thus, in this work, the objective was to evaluate the influence of proportions of elemental sulfur (source p.a) added to the vermiculite exploration residue on the release of nutrients in the soil. For this purpose, an experiment was carried out in a completely randomized design in a 5 × 8 factorial, with five proportions of elemental sulfur (0, 50, 100, 150 and 200 g.kg^-1) added to the vermiculite residue and eight incubation periods (0 , 15, 30, 45, 60, 75, 90 and 105 days of incubation) of the residue-sulfur mixture, with four replications, totaling 160 experimental plots. During 105 days of incubation, every 15 days, the available contents of K, Na, Ca, Mg, P, SO₄^-2 and pH values were determined in the soil-residue-sulfur mixture. The mining residue associated with elemental sulfur, provided in the mixture, significant increase in the contents of sulfate, calcium and phosphorus available, reduction of the pH and of the contents of K. The contents of Mg were not influenced by the addition of the 'additive', already in relation to Na levels, there was a significant increase. In conclusion, It is concluded that the sulfur-tailing mixture has the potential to increase the contents of some nutrients in the soil, however, its use may be limited in soils with drainage difficulties due to excessive accumulation of exchangeable sodium. (author)