Fertilization and containers in the seedlings production and post-planting survival of Schizolobium parahyba

Abstract

Fertilization in the production of forest seedlings can vary according to the substrate, container and fertilizer used in the nursery. Controlled release fertilizers (CRF) can be applied to reduce or even to eliminate the need for top-dress fertilization. The CRF doses can vary according to the container volume, considering the different amount of substrate available for seedlings in different containers. This study aimed to evaluate the growth of Schizolobium parahyba seedlings produced in plastic tubes of 110 and 280 cm3, with different doses of CRF (15-09-12) (0, 3, 6 e 12 kg m-3), as well as the seedlings survival and the initial growth after post-planting in the northern region of Rio de Janeiro state. The study was conducted using a factorial design 2 x 4 (tube volumes x CRF doses), with five repetitions for each treatment. As substrate it was used sewage sludge from urban areas, which was dried in open air beds. The growth of seedlings at nursery was evaluated at 93 days after the transplant, and the survival and initial growth at five and twelve months after planting. The Schizolobium parahyba seedlings showed higher growth in 280 cm3 tubes and responded positively to the CRF application, where the most efficient dose was 8.3 kg cm3 for this plastic tube. Twelve months after planting, seedlings from all treatments showed survival below 80%, being under the standard recommended for forest restoration. The mortality of seedlings occurred in consequence of five months of water deficit in a sandy clay loam soil. Considering only nursery data, the combination of 280 cm3 plastic tubes, with the CRF dose of 8.3 kg cm3 are recommended to produce Schizolobium parahyba seedlings.