Technical feasibility of the use of topsoil in the composition of substrates of Caatinga forest species

Abstract

Mining generates great environmental impacts, in addition to a large amount of waste. In order to comply with environmental legislation, the production of seedlings is one of the actions carried out, which requires a large volume of substrates, generally commercial. The topsoil it is a residue with physical-chemical characteristics with potential for agricultural use, present in large quantities, reaching 33 thousand m3. This research aimed to know the technical feasibility of topsoil added to commercial substrate for the production of seedlings of four native Caatinga species. The experiment was carried out in a completely randomized design, in a 5 x 4 factorial model, with five topsoil levels (0, 25, 50, 75 and 100%) and four species [‘Canafístula’ (Peltophorum dubium), ‘Farinha Seca’ (Albizia hasslerii), ‘Timbaúba’ (Enterolobium contortisiliquum) and ‘Ipê Branco’ (Tabebuia roseo-alba)]. Considering the Dickson quality index, for the species ‘Canafístula’ and ‘Ipê Branco’, 74.1 and 36.1% are the maximum limits of topsoil and, for ‘Farinha Seca’ and ‘Timbaúba’, up to 100% can be used. In general, the addition of topsoil to the substrate will allow savings of 77% in substrate costs, making its use in the production of forest seedlings economically viable and environmentally correct.