Fertilizer use and permanence time of sweet potato plantlets produced in trays

Abstract

The objective of this work was to evaluate the production of sweet potato plantlets in polystyrene foam trays, using slow-release fertilizer and to establish the proper permanence time for this plantlets to stay in trays. An entirely radonmized experimental design was used with 5x5 factorial arrangement, with five doses of osmocote slow-release fertilizer NPK 15-09-12 (0, 50, 100, 150 e 200 g per 25 kg of the substrate) and five permanence times in the trays (14, 28, 42, 56 e 70 days after planting, DAP). The number of roots and leaves, and their respective dry matter mass were evaluated. Furthermore, clod integrity as a function of the permanence time of cuttings in trays was evaluated in an experiment without the use of fertilizers. It was observed significant interaction between fertilizer doses and permanence time in the trays. The fertilization with 150 g increased the number of roots and leaves and the dry matter of new plantlets, after 14 DAP. Generally, clod integrity increases with permanence time. Nutritional deficiency symptoms were observed from 25 DAP, when no fertilizer was used. The permanence time in trays may be extended if the slow-release fertilizer is used.