Adubação verde com Crotalaria juncea afeta a produção de biomassa e o metabolismo de compostos voláteis e fenólicos de Lippia dulcis Trevir. (Verbenaceae)

Abstract

Medicinal plants are affected by several factors, including fertilization. Lippia dulcis is a medicinal plant used in the treatment of coughs, colds and bronchitis. It presents in its chemical composition essential oils and phenolic compounds, including verbascoside. The objective was to evaluate the influence of green manuring (GM) with Crotalaria juncea on vegetative growth and accumulation of essential oil, total phenolic compounds and verbascoside in Lippia dulcis. The experiment was conducted in the field and has seven treatments: Soil and sand substrate; Fertilization with cattle manure (450 g/10 L per pot); Chemical fertilization; Green manure with 150g per 10 L pot; Green manure with 300 g per 10 L pot; Green manure with 450g per 10 L pot; Green manure with 600 g per 10 L pot. The dry weight was evaluated; leaf analysis; levels of photosynthetic pigments, total phenolics, total flavonoids and verbascoside; and, content, yield and chemical analysis of the essential oil. For plant biomass, the most significant treatment was with the use of 600 g of GM. For the essential oil content and yield, were the doses of 450 and 600 g of GM. For verbascoside and total flavonoids it was the control treatment. For phenolic compounds, the most significant treatments were chemical fertilization and GM at a dose of 300 g. Therefore, green manuring was positive for the cultivation of the Lippia dulcis species. In addition to being a cheaper and more sustainable strategy in the cultivation of medicinal plants.