NITROGEN, PHOSPHORUS AND POTASSIUM CONTENT IN DIFFERENT ORGANS OF PINEAPPLE CULTIVARS AT DIFFERENT PLANTING DENSITY

Background. The amount of nutrients required by pineapple varies depending on the cultivar and planting density. Knowing the nutrient requirement in quantity and the appropriate phenological stage will allow the development of an adequate fertilization program. Objective. To determine the effect of pineapple cultivar and planting density on N, P, and K content during plant development and at harvest. Methodology. The cultivars 'Smooth Cayenne', 'Champaka', and 'MD-2' were established at 30000, 45000, and 60000 plants ha-1. Eight samples were taken to determine the N, P, and K content in the organs and the total plant. Results. The highest and lowest N, P, and K contents were detected in the leaf and root, respectively. The highest N and K contents occurred at 441 - 506 days after planting. Higher P content occurred close to harvest. The highest N, P, and K contents per plant were at 30000 plants ha-1 (14.86, 1.52, and 16.29 g plant-1, respectively) and the lowest at 60000 plants ha-1 (10.16, 1.13, and 14.6 g plant-1, respectively). Higher N, P, and K contents per hectare were detected with 60000 plants ha-1 (609, 68, and 875 kg ha-1, respectively).  At harvest, ‘Smooth Cayenne’ at 60000 plants ha-1 accumulated the highest amount of N, P, and K (147, 37, and 306 kg ha-1, respectively). Implications. The changes that can occur in the nutrient requirements of pineapple as a function of cultivar, planting density, and stage of plant development were identified. This information will be useful for producers, agricultural technicians, and researchers in Mexico and the world, to generate fertilization programs or establish new research. Conclusion. At the beginning of plant growth, a higher N, P, and K contents in the leaf, this amount decreases as the fruit harvest approaches. Regardless of cultivar, the highest nutrient content per plant occurs at the lowest planting density, however, the highest content per hectare occurs at the highest planting density. At harvest time, fewer nutrients are removed from the soil with 'Champaka' and 'MD-2' fruit.