Availability of nutrients and toxic heavy metals in marigold plants/Disponibilidade de nutrientes e metais pesados toxicos em plantas de calendula

Availability of nutrients and toxic heavy metals in marigold plants. This study was performed aiming to assess the availability of nutrients and toxic heavy metals present in marigold plants (Calendula officinalis) treated with different fertilizers. The treatments were arranged in factorial scheme (2 x 2 x 3) in a completely randomized experimental design (CRD), with two textures of soil (sandy and clayey), two forms of fertilization (organic and chemical) and three fertilization levels (without fertilization, recommended dose, and twice the recommended dose) totaling 12 treatments, with four replications. The results showed that the clayey soil promoted the availability of N P, K, Mg, Cu, Zn and Fe; on the other hand, the sandy soil favored the availability of Ca, Mn, Pb and Cr. The organic fertilization provided higher levels of P and Fe, while the leaf tissue of marigold plants chemically fertilized presented higher concentrations of K and Mn. Keywords: medicinal plants, chemical fertilization, organic fertilization. Realizou-se este trabalho com o objetivo de avaliar a disponibilidade de nutrientes e de metais pesados toxicos presentes em plantas de calendula (Calendula officinalis) apos diferentes tipos de adubacao. Os tratamentos foram arranjados em esquema fatorial (2 x 2 x 3) dispostos em delineamento experimental inteiramente casualizado (DIC), sendo duas texturas de solo, (argilosa e arenosa), duas formas de adubacao (quimica e organica) e tres doses de adubacao (sem adubacao, dose recomendada e o dobro da dose recomendada), totalizando 12 tratamentos com quatro repeticoes. Os resultados demonstraram que os solos argilosos favoreceram a disponibilidade de N P, K, Mg, Cu, Zn e Fe; os solos de textura arenosa favoreceram a disponibilidade de Ca, Mn, Pb e Cr. A adubacao organica disponibilizou maiores teores de P e Fe, enquanto o tecido foliar de plantas de calendula adubadas com adubacao quimica apresentaram concentracoes maiores de K e Mn. Palavras-chave: plantas medicinais, adubacao quimica, adubacao organica.