Dosagens de adubação de cobertura na produtividade inicial e sobrevivência de eucalipto em Pernambuco

Abstract

Energy generation from biomass coming from planted forests, in addition to being a sustainable energy source, is an opportunity to create a viable alternative to the demand for biomass from wood in the state. Considering the edaphoclimatic characteristics of the region, the scarcity of studies on the subject and the importance of fertilization, as one of the silvicultural practices that provides greater gains in wood productivity, this experiment aims to evaluate the silvicultural behavior of eucalyptus clones in an area of transition between Zona da Mata and Agreste Pernambucano, in relation to growth and yield when subjected to different doses of top dressing. The research was carried out in a clonal eucalyptus plantation, implemented in 2018, in the municipality of Glória do Goitá, on a farm leased to the company BRF. The experiment with different doses of topdressing fertilization (NPK) and the addition of foliar boron applied when the stand was 15 months old was initially carried out with measurements of DBH and tree height in 32 plots with 8 treatments and 4 replications. The first measurement was carried out 15 months after planting and the second after 24 months after planting, to assess which dosage of top-dressing results in better indicators of productivity and survival. Through regression obtained through destructive sampling of biomass, individual volumes were estimated using the Schumacher & Hall equation. The volume was extrapolated to the total area (m³/ha) and the indicators of productivity average annual increment (IMA) and current annual increment (ICA) between the two measurements were estimated. The volume per treatment of the plots in the first measurement was 7.2 m3/ha and in the second measurement 16.3 m3/ha, and the IMA respectively 5.77 m3/ha/year and 8.16 m3/ha/year, resulting in a Current Annual Increment (ICA) of 10.92 m3/ha/year. The results at 24 months of planting show the relative gain in productivity was 28% to 58%, with the maximum gain for the dosage of treatment 8 (250% of the usual dose adopted by the company, 535kg/ha). In statistical analysis by regression, we obtained a significance level of 5% for boron-free fertilization, when we correlated the ICA with the fertilizer dosages, showing that there is a trend of growth from a statistical point of view. The experiment will continue to be analyzed in the coming years and new fertilization with fertilizer and foliar boron will be carried out, to verify if the productivity gain keeps increasing and if the mortality rates remain low.