Silvicultural Potential of Handroanthus heptaphyllus Under Doses of Controlled Release Fertilizer and Container Volume, in Nursery and in the Field

The present study aimed to characterize the growth of Handroanthus heptaphyllus seedlings in a nursery, planted under different container volumes and doses of controlled release fertilizer (CRF), and to verify whether the responses obtained in the nursery are confirmed in the field. For the production of seedlings in the nursery, three volumes of container (180 and 280 cm3 polypropylene tubes and 500 cm3 polyethylene bags) and four CRF doses (0, 4, 8, and 12 g L-1 of substrate) were used. At 180 d after emergence, height (H), stem diameter (SD), H-SD ratio, shoot dry weight, root dry weight, total dry weight, Dickson Quality Index, leaf area, root length, and fluorescence of chlorophyll a were evaluated. The same treatments were evaluated again in the field 540 d after planting, and the survival, increase in H and SD, as well as shoot dry weight, leaf area, chlorophyll fluorescence, and chlorophyll index (a, b and total) were measured. In the nursery, seedlings of H. heptaphyllus responded positively to the volume of the container, as well as the base fertilization using CRF. However, when planted in the field, the plants that received the best nutritional conditions in the nursery showed good performance and was favored in the field. Thus, in the production of quality seedlings, the use of containers of the type polypropylene tubes with 180 cm3, and basic fertilization with 12 g L-1 of CRF conditions that enable growth of H. heptaphyllus in the field are recommended.