Doses de adubação nitrogenada e potássica em cobertura na cultura da cana-de-açúcar, primeira soca, com e sem irrigação

Abstract

This research had the objective of evaluating the effect of different manuring levels of N and K2O on the growth and yield of the sugar-cane (Saccharum spp, cultivate SP79 1011) first leaf, cultivated with and without irrigation. The experiment was conducted in the farm of the Miriri distillery, in the municipality of Capim, Paraíba state. The experimental scheme had a factorial type 2 x 4 (with and without irrigation and four levels of manuring of N and K2O) with three replications. The water irrigation depth used, 27.5 mm, was applied in intervals of 12 days. The manurings were composed of the elements N and K2O, in levels based on recommendations of the consultants of the Miriri distillery, equal to AC1 = 44 kg ha-1 of nitrogen and 41 kg ha-1 of potassium, AC2 = 86 kg ha-1 of nitrogen and 81 kg ha-1 of potassium, AC3 =157 kg ha-1 of nitrogen and 148 kg ha-1 of potassium, and AC4 =236 kg ha-1 of nitrogen and 222 kg ha-1 of potassium. When submitted to irrigation, the crop presented better yield in all appraised variables. In the irrigated parcels, the manuring affected significantly, through a positive linear behavior, the production of stems, sugar and alcohol, while in the non-irrigated parcels this effect was shown only for the production of stems. The maximum level of manurring in this work was not enough to get the maximum yield colm peak, using irrigation management or not.