Growth of Didymopanax morototoni seedlings as a function of doses of controlled-release fertilizer

The species Didymopanax morototoni, commonly known as morototó, presents great potential for the timber industry and the recovery of degraded areas, but the absence of adequate technical standards for seedling production limits its success in the field. The use of controlled-release fertilizers (CRF) is an alternative to conventional fertilizers, as it reduces costs and losses. The authors of this study aimed to evaluate the effect of different doses of Osmocote® fertilizer on the growth characteristics and seedling quality of D. morototoni. The experiment was conducted in a nursery, using a randomized block design, testing five doses of Osmocote® (0, 2, 4, 6, and 8 g dm-3), with an NPK 18-5-9 formulation and a release period of five months. After 150 days, height, collar diameter, number of leaves, root length, leaf area, chlorophyll content, dry mass, and Dickson Quality Index were evaluated. The data were subjected to ANOVA and regression analysis (α = 0.05), and the dose of maximum technical efficiency (DMTE) was calculated using the derivative of the fitted equations. The results showed that the controlled-release fertilizer significantly influenced on the increase of all analyzed variables compared to the control. The most effective dose was 3 2 g dm-3 of Osmocote® 5M 18-5-9 mini prill, which provided the highest DQI for the production of D. morototoni seedlings.