INPUTS OPTIMIZATION IN THE SEEDLINGS PRODUCTION OF Corymbia citriodora E Eucalyptus dunnii

Corymbia citriodora and Eucalyptus dunnii are species of relevant importance due to the quality of the wood and growth potential in Southern Brazil. Therefore, we aimed to identify containers and doses of controlled-release fertilizer capable of enhancing the morphophysiological quality and growth of these species in the nursery, aiming for the proper management of these inputs. The seedlings were produced in two volumes of containers (50 e 110 cm³), filled with Sphagnum peat-based substrate, mixed with different doses of controlled-release fertilizer (CRF) NPK 15-09-12 (0, 3, 6, 9 e 12 g L-1 of substrates). In addition, the morphological (height, stem diameter, leaf area, dry weight of shoot, root, and total) and physiological (chlorophyll a and b index and quantum yield of the photosystem II) attributes were evaluated. The morphological attributes proved to be suitable indicators of the quality of C. citriodora and E. dunnii seedlings, allowing to recommend the container of 50 cm³ and the doses of 9.0 g L-1 of controlled-release fertilizer for both species. At the same time, the physiological variables evaluated were not responsive to the effect of the treatments.

Remineralizer and controlled-release fertilizer increase Mimosa scabrella Benth. seedlings growth

Contextualization: M. scabrella is a native tree species of the Brazilian Mixed Ombrophilous Forest, with a high ecological importance and economic potential. Knowledge gap: There is a lack of information about the use of resources that favour the seedlings production of this species. Purpose: This study aimed to determine the most appropriate doses of controlled-release fertilizer (CRF) combined with the addition of remineralizer for production of M. scabrella seedlings. Methodology: Seedlings were produced using four doses of CRF (0, 4, 8, and 12 kg m-3) and four doses of remineralizer (0 %, 10 %, 20 %, and 30 %), in a 4 x 4 factorial scheme. At 180 days of seedling production, growth in height and stem diameter, shoot (SDB), root (RDB) and total biomass (TDB), and Dickson quality index (DQI) were evaluated. Results and conclusions: The use of remineralizer provided an increase in density and water retention capacity of substrates, as well as a reduction of macroporosity and total porosity. Combined with doses of 4 and 8 kg m-3, CRF contributed to the increase of biomass and DQI. The addition of 10 % remineralizer, associated with 4.0 kg m-3 CRF, provides adequate growth to produce M. scabrella seedlings. Above this percentage of remineralizer and CRF dose, species growth rate is reduced.