Adubação nitrogenada, potássica e fosfatada influenciando a qualidade e durabilidade pós-colheitta de gladíolo

Abstract

The gladiolus is one of the most cut flowers produced and commercialized in Brazil and worldwide. This work, conducted in Dourados-MS, during the period of November 2010 to January 2011, aimed to evaluate the use of fertilization potassium and nitrogen associated with different sources and doses of phosphorus in quality and durability in post harvest of gladiolus (Gladiolus hortulanus L. cv. T704) cultivated in oxisol. We used a split-plot completely randomized design. Each plots were allocated in the presence or absence of nitrogen of fertilization and potassium fertilization subplots were assigned to the sources of phosphorus which consisted of single superphosphate (SSP), triple superphosphate (TSP) and bone meal (BM)., and in the sub-subplots were allocated five doses of P (0, 75, 150, 225 and 300 kg ha-1) of each fertilizer studied. Were evaluated on the number of colored buttons (NCB), total number of buttons (TNB), number of open flowers (NOF), leaf quality (LQ), flower quality (FQ), quality of the stem (QS), plant height (PH), length of the floral spike (LFS), flower diameter (Diflower) and flower durability (FD). Regardless of treatments and combinations studied, the leaves produced and evaluated in the post-harvest were classified as optimal. The combined action of the three factors studied (p <0.05) was observed only on the durability of potted flowers. The highest value (84h37min) was obtained with the use of NK fertilization associated with the calculated dose of 161.11 kg ha-1 TSP. Using isolated NK stems submitted to post-harvest showed a number of open flowers equal to 0.18, the quality of flowers equals to 8.18; quality of flower spike equal to 0.78 and height of the stems equal to 1.11 m, values statistically superior to those observed without the addition of NK (0.50, 7.88, 1.36 and 1.07 m, respectively). The use of single superphosphate led to 7.52 colored buttons better (p <0.05) than the results observed for the other two sources (TSP = 8.08 buttons, buttons BM = 8.40). Based on the observed results we can conclude that the use of NK fertilization is essential for obtaining a quality class I gladioli and values between 150 and 160 kg ha-1 of triple superphosphate are effective to quality of the stems produced and the durability with use of the source superphosphate.