Subprodutos da mineração de calcário da Formação Irati como fontes de cálcio, magnésio e enxofre

Abstract

Mining is a natural resource exploration that can cause environmental impacts. To promote an appropriate destination for the byproducts of mining is fundamental for economic and environmental return. In this sense, this research has seek to evaluate the use of byproducts from the limestone mining as calcium, magnesium and sulfur sources. For this, three studies were carried out. The first was conducted in a greenhouse and a Paleudalf soil was used. The inputs evaluated were limestone, 1ª and 2ª haste (byproducts). The rates were: 0; 0.5; 1; 2 and 4 times the recommended rate according to the SMP pH of the soil and PRNT of the limestone for soil correction up to pH 6. The experiment was carried out in pots containing 3.54 kg of dry soil kept at a humidity near to the field capacity. A weekly determination of soil pH was carried out until its stabilization, and after a period of 4 months of input-soil incubation, the determination of the available macronutrient contents of the soil was carried out. After that, the second study was started, where NPK fertilizer and corn applied. Corn plants were harvested at the V7 stage and had their dry aerial mass and macro and micronutrient contents evaluated. The third study was carried out in a greenhouse with a two soils, Paleudalf and an Albaqualf. The inputs used were: mixing of 1st and 2nd layer, limestone, CaCO3 p.a., MgCO3 p.a. e CaSO4.2H2O. Based on soil SMP pH and PRNT of the inputs, different amounts of soil source were used for soil correction until pH 6. The culture chosen (onion) was sown in floating trays with substrate and, after transplanting for pots containing 10 dm³ of soil kept at a humidity near to the field capacity. At that time NPK inputs and fertilizers were applied. Two phytomass (bulb + leaves) were harvested. The first was at 49 and the second at 77 days after transplanting. After that, the soil macronutrients, dry phytomass and macro and micronutrient contents of the phytomass of the onion were determined. The byproducts of limestone mining have been shown to have the potential to correct soil pH, but at higher rates than limestone. The application of the byproducts, in general, provided higher levels of Ca, Mg and S in the soil and in the plant, besides a greater accumulation of the same nutrients. The byproducts provided an increase in the dry mass of the aerial part of the corn crops. For the onion, in general, there was no statistical difference between the inputs.