Effect of liming and shadow on yield and essential oil content of "carqueja" (Baccharis trimera A. P. de Candolle)

Abstract

Popularly known as "carqueja", the Baccharis trimera A. P. de Candolle is very used by its medicinal effect, being target of irresponsible extraction due to the great demand for the phytotherapeutic industry. The present work had as objective to quantify the influence of liming levels over mass production and shadow over essential oil content of "carqueja", aiming to release information to increase the species cultivation efficiency. The liming experiment was conducted in the greenhouse of the Departamento de Fitotecnia e Fitossaniratismo of the Setor de Ciências Agrárias of UFPR, in Curitiba PR and the shadow experiment was accomplished in the Section of Medicinal Plants of the Estação Experimental do Canguiri, in Pinhais PR. For the liming experiment, Cambissolo Alico of loamy texture, collected from 10 to 30 cm of depth, dry, sifted and chemical analyzed was corrected with fast reaction Füller limestone and placed in vases with capacity of 1L. The correction was calculated to V% 70, being considered 1 dose the amount of limestone necessary to reach this level. The tested treatments were 0 dose; 0,5 dose; 1 dose and 1,5 dose of limestone. The design used was completely randomized, with four repetitions and six vases for experimental unit. Plantlets of "carqueja", with approximately two months, proceeding of cutting propagation were used. The evaluation of the fresh and dry masses of the whole aerial part was accomplished 105 days after the installation. In the experiment of different shadow levels it was made the comparison of three stonemasons of 6,48 m each, contends 72 plants with 16 months of age in spacing of 30x30 cm. Plants exposed to full sun, with 30% and 70% of shadow were the treatments used. Evaluation was accomplished after 5 months of the installation of the covers and a second evaluation was made after 5 months from the first one. There were evaluated the fresh and dry mass of the plants which were cut at 15 cm of the ground, as well as there were made the extraction and determination of the percentage of essential oil in the different treatments. In the liming experiment, the amount of fresh and dry presented a quadratic behavior, increasing the production until the saturation of bases of 50,1% for fresh mass and 44,4% for dry mass. In the different shadow levels experiment, in both first and second cuts, the amount of mass was larger in the full sun exposed plants, presenting loss of approximately 50% in the shaded plants production, and an increase of 12,5% in the oil content in the full sun exposed plants. It is indicated a V% of 44,4 to increase production of dry mass. Shadow decreases the amount of fresh and dry mass, as well as the oil amount.