FOLIAR NUTRIENT CONCENTRATION AND MICRONUTRIENT UPTAKE IN THREE PINEAPPLE VARIETIES ESTABLISHED AT DIFFERENT PLANTING DENSITIES

<p><strong>Background.</strong><strong> </strong>The amount of micronutrients required by pineapple changes according to different factors, including cultivar and planting density. Knowing the micronutrient requirement in quantity and the appropriate phenological stage will allow the development of an adequate fertilization program. <strong>Objectives.</strong> (1) to determine the content of Cu, Fe, Mn, and Zn during the development of three pineapple varieties, at three planting densities; (2) to determine the effect of planting densities on the foliar concentration of N, P, K, Ca, Mg, Cu, Fe, Mn, and Zn during the vegetative stage of the plants; (3) to determine the effect of foliar concentrations on the total micronutrient content at harvest. <strong>Methodology.</strong> The varieties 'Smooth cayenne', 'Champaka' and 'MD-2' were evaluated at densities of 30 000, 45 000, and 60 000 plants ha<sup>-1</sup>. The experimental design was a randomized block. The treatments were arranged in a split-plot design, with four replications. The Cu, Fe, Mn, and Zn contents were determined in eight samplings, and the concentrations of N, P, K, Ca, Mg, Fe, Mn, Cu, and Zn were measured in the first five samplings. <strong>Results.</strong> Higher Cu, Fe, Mn, and Zn content per plant was detected at 30,000 plants ha-1, but higher extraction per hectare was observed at 60,000 plants ha<sup>-1</sup>. Similar Fe, Mn, and Zn contents were detected among varieties. No defined behavior of nutrient concentration was detected in leaf D. In the three varieties, a high Pearson correlation (r ≥ 0.5) was detected between concentrations and total micronutrient content at 3.6, 4.6, 6.3, 8.6, and 10.1 months of age. <strong>Conclusions. </strong>The amount of Fe, Mn, Cu, and Zn extracted increases as planting density increases, reaching maximum values of 12.7, 6.2, 1.2, and 0.6 kg ha<sup>-1</sup>. The Fe extraction of the cv. 'MD-2' is 30% lower than that of the 'Smooth cayenne' and 'Champaka'. A high correlation between leaf nutrient concentration and total Fe, Mn, Cu and Zn content was detected only 18% of the time during the flower induction stage (at 10.1 months of age). A high correlation was detected 82% of the time in samples taken between 4 and 9 months after planting. Leaf analysis was found to be most effective for predicting Fe and Zn behavior, but less effective for Mn and Cu behavior in leaf D.<strong></strong></p>