Paulo Henrique Carvalho de Castro

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.

The growing demand for native seeds in forest restoration projects highlights the importance of technical and technological knowledge in the propagation and maintenance of forest species. Seed coating can facilitate direct seeding of these species. However, although the polymer polyvinyl alcohol (PVA) and the plasticizer glycerol have been studied for coating agricultural seeds, there is a lack of information about their behavior in forest species. Therefore, the objective of this research is to evaluate the applicability of film coating using polyvinyl alcohol and glycerol on forest seeds, specifically Enterolobium schomburgkii, and evaluate its influence on germination. The first experiment determined a suitable formulation for coating, for which three concentrations of PVA (1%, 3% and 5%) and glycerol (10%, 20% and 30%) were evaluated. To evaluate the effect of coatings on germination, a control was included, totaling 40 plots. Thickness, water vapor permeability, solubility and germination tests were carried out. The combination of 5% PVA and 10% glycerol was appropriate for coating E. schomburgkii seeds due to its properties and lack of deleterious effect on germination.