Growth and Quality of Inga heterophylla Willd Seedlings According to the Slow Release Fertilizer

Slow release fertilizers have become an alternative for better efficiency in substrate fertilization for seedlings production, however, there are not many studies approaching the use of such fertilizers in the production of native forest species seedlings. This work aimed to evaluate the effect of different doses of a slow release fertilizer (SRF) on the development and quality of the Inga heterophylla seedlings. The experiment was conducted in a vivarium with 50% of shade for a 150-day period. Randomized blocks were the chosen experimental design, constituted of four treatments and four replications, with twenty plants per experimental unit. The treatments were four doses of Osmocote® FLL (0, 4.1, 8.2 and 12.3 g dm-3) in NPK 15-09-12 formulation, with evaluated variables being the height of the seedling (H), collar diameter (CD), number of leaf pairs (NLP), leaf area (LA), aerial part dry mass (APDM), root dry mass, total dry mass (TDM) and Dickson quality index (DQI). All the evaluated parameters responded significantly to the SRF doses and fit the positive quadratic polynomial model. For all of the analyzed variables, results show that the best averages were obtained by using the doses between 5.7 and 6.5 g dm-3, but due to the quadratic response they presented a decrease in the mean values after doses which were superior to the maximum performance point of each characteristic.