PRODUÇÃO DE BIOCHAR A PARTIR DE RESÍDUOS DA COLHEITA DE PINUS E SEU USO NA COMPOSIÇÃO DE SUBSTRATOS PARA PRODUÇÃO DE MUDAS

Abstract

Forest harvesting operations generate significant amounts of residue that, although they can be kept in the field as a soil management practice, when in large quantities, can end up affecting the development and conduct of planting. Pine forest harvesting generates, in its operations, three main residues, namely: needles, bark and wood (tips and branches), which could be better reused. One of the ways of using it is its thermochemical conversion, using the pyrolysis technique, to produce biochar. Biochar is a product rich in carbon, with a porous constitution, which has a range of uses, contributing to the reduction of CO2 emissions, as an agent for removing pollutants from water, as well as a management practice, contributing to the correction of acidity and even availability of nutrients and can even return to the beginning of the production process, in the composition of substrates for seedling production. In this way, the study aimed to evaluate the quality of Eucalyptus benthamii seedlings, produced with the addition of biocharfrom Pinus taeda harvest residues in the composition of the substrates. The characterization of the waste generated during the Pine harvest was carried out and the material was subsequently taken to a pyrolysis reactor to produce biochar. Physicochemical characterizations of the biochar, BET analysis and FTIR analysis were carried out in order to evaluate its properties. Afterwards, biochar was incorporated into the composition of the substrates, in three proportions (15, 30 and 45%), and the characterization of the substrates was carried out, in order to evaluate the effect of biochar on their composition. In the last stage, Eucalyptus benthamii seedlings were produced in a greenhouse, in order to evaluate the effect of biochar on the growth and quality of the seedlings. The results demonstrated that the waste has potential characteristics for biochar production, such as carbon and ash content, porosity, particle size and shape. The biochar produced from the residue showed good yield and, from its characterization, it was possible to identify properties that make it suitable for use in the composition of substrates, as it presented characteristics that are required for substrates, such as high ash and carbon content, low density and high porosity. The evaluation of the quality of Eucalyptus benthamii seedlings demonstrated that pine needle biochar, in proportions of 30 and 45%, presented better results for the morphological properties evaluated, such as length of the root system, aerial and root dry mass, dry mass total and Dickson quality index. It was concluded, then, that residues from Pinus taeda forest harvesting had potential as a feedstock for the production of biochar, which demonstrated potential for use in the composition of substrates, acting as a conditioner.