Potencial de uso de biocarvão como substrato e na dinâmica do carbono do solo na cultura do eucalipto

Abstract

The debarking of tree logs carried out by industries generates a large amount of waste. It is essential to develop strategies for the management of these wastes. Therefore, using them in the production of biochar becomes a viable alternative, since biochar is considered a soil conditioner, improving physical, chemical and biological properties. Thus, the objective of this study was: (1) to evaluate the effects of doses of the addition of eucalyptus bark biochar, produced under different temperatures, on the quality of Eucalyptus grandis seedlings and (2) to evaluate the effect of the application of doses of eucalyptus bark biochar, produced under two pyrolysis temperatures, on different organic carbon compartments and soil biological attributes under eucalyptus cultivation. Biochar was produced from eucalyptus bark residues. In chapter 1, the substrates were composed of coconut fiber, vermiculite and biochar with four pyrolysis temperatures (250, 350, 450 and 600 °C) and five concentrations of biochar (0; 2.5; 5; 10 and 15% of the v/v). The substrates were physically and chemically characterized and chemical and morphological analyzes were performed on the seedlings. In chapter 2, two pyrolysis temperatures (350 and 600ºC) and five doses of biochar (0, 0.25, 0.5, 1 and 2% of the volume/volume considering the soil volume of the planting furrow) were used), previously distributed in the planting furrow (30 cm depth). At 730 and 913 days after planting eucalyptus, soil samples were taken to evaluate the effect of treatments on biological attributes and related to organic matter. The experimental results showed that the substrate composition with the addition of biochar provided adequate nutritional supplies to the seedlings and good root quality, with satisfactory development for seedling expedition, however, treatments T16 and T17 were inferior to the others, not being recommended. The addition of biochar to the soil promoted an increase in total organic carbon and more stable carbon fractions over time for the two pyrolysis temperatures, in both soil layers. Microbial biomass carbon and microbial quotient reduced with increasing doses of biochar. Climatic conditions provided 913 days after planting (2nd evaluation) reduced soil microbial activity.