This work was carried out at the Universidade Federal do Parana, Paraná State, Brazil, from October 2005 to June 2006. The effect of organic fertilization with sheep manure was evaluated on Ocimum gratissimum development and the viability of this practice was determined to increase biomass and essential oil yield and quality. The plants were spaced 0.5 m from each other in the experimental units which were separated in 1 m. Three rates of organic fertlization (4; 8 and 12 kg m-2) were compared to control (without fertilizers), with 5 replications and 8 plants by experimental unit. Plants were harvested 150 and 226 days after planting, and the total, leaves, flowers and stems fresh and dried biomass, essential oil yield from leaves and flowers and composition by GC/MS beign evaluated. There was significant difference among the treatments on biomass production at the first harvest, where the plants treated with 8 kg m-2 of organic fertilizer presented higher flowers fresh biomass, and flowers and total dry biomass than plants without fertilizer (control plants), but with no difference compared to other organic fertilization levels. At the second harvest there were no differences among treatments. Regarding the essential oil yield no differences were found comparing the organic fertilization levels in both harvest times. In addition, the essential oil composition was similar on plants from all treatments. However, some variations in composition were observed when the essential oil was extracted from flowers and leaves, where the eugenol percentage was 90.4% on leaves and 80.8% on flowers at the first harvest. At the second harvest, a reduction of eugenol content and an increase of alpha trans trans farnesene, beta bisabolene, beta cariophilene, germacrene D and alfa selineno was found.
Ocimum gratissimum; organic compost; yield
