Use of Emerald Mining Tailings From the Esmeraldifera Province Between Itabira and Nova Era – MG, As a Supplier of Nutrients to Agricultural Soils
Two experiments were conducted in a laboratory with incubation of mineral tailings formed predominantly by emerald-biotite-amphibole-mica quartz schist on soil with and without plants. The first experiment evaluated the release of exchangeable Mg+2, Ca+2 and K+, change in pH, soil aluminum saturation and soil base saturation. The methodology used was to incubate 0, 1, 2, 4, 8, 12, 16, 20, 40 t/ha of tailings for 60 days. The second experiment evaluated the dry matter production of hybrid corn for doses, used in the form of rock dust, of 0, 5, 10, 20, 40 t/ha. A completely randomized design was used with four replications in the first and five in the second. The standardized particle size of the tailings was < 0.500 mm. The ability of the mineral tailings to release Mg+2 and K+ to the soil varied according to dosage. With the doses tested, alterations were observed in the values of potassium, reaching 250 mg/dm3 in the dose close to 20 t/ha. For the magnesium, the altered levels varied with values of 0.30 cmol/dm3 in the untreated control and values above 1.5 cmol/dm3 for the dose close to 20 t/ha. For calcium, the change in the soil was not positive. For the period analyzed, there was no significant change in the pH of the soil. Regarding the aluminum saturation, there was a 60% decrease for the dose of 40 t/ha. For base saturation, there were increases ranging from 7% to 34% for the doses 1 t/ha and 40 t/ha. In dry matter production of hybrid corn compared to the control, the increments of the values were approximately 350 g/pot with increases of 78%. The chemical characteristics of the tailings, coupled with the low concentration of Potentially Toxic Elements (PTE), encourage technical studies and research into chemical or biochemical interventions to improve the release of nutrients, which could increase their agronomic efficiency.