PRODUCTION OF ESSENTIAL OIL AND NUTRIENT BUDGET IN Corymbia citriodora FERTILIZED WITH SEWAGE SLUDGE IN DIFFERENT SPACING

Abstract

The Corymbia citriodora is one of the most cultivated species in Brazil for wood and essential oil production. The oil is obtained by the leaves distillation and the yield is around 2%. For the sustainability of leaves extraction is necessary a good nutritional replacement, because the leaves contain a large quantity of nutrients. The sewage sludge application in Corymbia plantations is a way to apply organic fertilizer and is also a good alternative for the final disposal of this residue. In this context, the objective of this study was to evaluate the sewage sludge use as fertilizer for the essential oil production in two different spacing. The experiment was constituted by 4 blocks and the treatments were: i) Close spacing (1m x 1m) with sewage sludge + K and B; ii) Close spacing  with mineral fertilization; iii) Regular  spacing (3m x 1m) with sewage sludge + K and B; and iv) Regular spacing with mineral fertilization. When the C. citriodora plots were 12, 18, 24 and 30 months old; leaves and branches biomass and also essential oil production were quantified. It was observed that the system of close planting totalized a higher biomass, 3.8 times more than the conventional system, providing 3 times more essential oil production (363 l ha^-1 at the close spacing and 116 l ha^-1 at the regular spacing during 30 months). No difference was found in the leaves or oil production with the use of sewage sludge or mineral fertilizer any of spacing studied. The use of sewage sludge as fertilizer for Corymbia citriodora plantations may be an interesting alternative, because it supplies large quantities of nutrients and ensures a positive budget of nutrients in the ecosystem.