STRATEGIES FOR NITROGEN AND POTASSIUM FERTILIZATION FRACTIONATION VIA FERTIGATION IN EARLY GROWTH OF CONILON COFFEE PLANTS
Fertigation is an important strategy to increase nutrient use efficiency in irrigated coffee cultivation, especially in Coffea canephora crops. The objective was to evaluate early growth and biomass accumulation of Conilon coffee plant clone R08 submitted to different nitrogen and potassium fertilization fractionation strategies via fertigation. The experiment was conducted in a greenhouse, in a completely randomized design with split-plots in time and five replications. Four NK fertilization fractionation strategies were evaluated: single application of the recommended dose (100%), fractionation in two applications (50%), four applications (25%), and ten applications (10%). Evaluations were performed at 30, 60, 90, 120, and 150 days after planting (DAP), determining dry mass of shoot, root, and total. Data were submitted to analysis of variance, Tukey test (p≤0.05), and polynomial regression. A significant interaction was observed between evaluated factors for all analyzed variables. Less fractionated treatments promoted higher initial growth up to 90 DAP due to greater immediate nutrient availability. However, from 120 DAP onwards, the treatment with ten fractionations showed superior performance, providing greater accumulation of shoot, root, and total biomass. At 150 DAP, this management promoted an 11.54% increase in total dry mass compared to single fertilization application. Frequent fractionation of NK fertilization via fertigation favors greater synchronization between nutrient supply and physiological demand of plants, increasing nutritional efficiency and vegetative growth of Conilon coffee plants in early development phase.