Content and distribution of micronutrients in calendula (Calendula officinalis) grown in Valle del Cauca, Colombia

Calendula productivity depends on the nutritional demands of the crop. Knowledge of the nutritional requirements of calendula at its different phenological stages will allow the producer to improve fertilization programs. The objective of this research was to evaluate the content and distribution of essential micronutrients and beneficial elements in different organs and stages of development of calendula under field conditions. An experiment was set up in the municipality of Yumbo, in the Department of Valle del Cauca in Colombia, using a completely randomized design with five treatments related to the stage of development of the plants (2, 3, 5, 6 and 7 months after transplanting). Each treatment had three replicates. Leaves, stems, flowers and seeds were collected every month after transplanting to analyze the concentrations of Mn, Fe, Zn, Cu, B, and Na. The concentration of nutrients differed significantly between organs and stages of development. Calendula accumulated nutrients in descending order (from highest to lowest) as follows: Na>Fe>Mn>B>Zn>Cu. The highest concentrations of Na, Mn, Zn, B and Cu were found in the leaves and of Fe in the flowers. Among the phenological stages, the highest values of Na were recorded in the second and sixth months, B and Fe in the fifth month, Cu and Zn in the third month, and Mn in the third and fifth months. Thus, the stages and organs on the plant with the greatest nutrient accumulation were identified.