Biomass production and essential oil of Plectranthus neochilus Schlechter cultured in field under increasing doses of organic manure

Abstract

With the purpose of evaluate increasing doses of organic manure in Plectranthus neochilus Schlechter plants, this work studied dry biomass production from vegetal material, content and essential oil yield. The experiment was conducted in an experimental field at the Federal University of Lavras (UFLA) in 2006. The scions, after been acclimatized were taken to field and transplanted to beds. It was used randomized complete block design with three replications of five parcels each. The parcels were made of 16 plants; the four central ones were considered the useful parcel. The treatment had 5 cattle manure doses: 0.0; 2.5; 5.0; 7.5; 10.0 kg m^-2. The plants were harvested at 180 days old, part of the fresh leaves were for essential oil extraction and the rest of the vegetal material were sent to an oven to dry until they had a constant mass for the dry biomass verification. The essential oil content and yield calculation were done from the mass from the oil extraction. The increasing doses of cattle manure tested gave a linear increase in biomass production and essential oil yield in Plectranthus neochilus plants; it was not observed the maximum curve in the studied period of time. The different cattle manure dosages used did not modify the volatile oil content.