Deficit irrigation strategies and potassium fertilization in the cultivation of banana cv. Nanicão

ABSTRACT This study aimed to evaluate the effects of potassium fertilization on gas exchange and production of banana under water deficit irrigation strategies. The experiment was conducted at the experimental farm belonging to the Center of Science and Agri-Food Technology of the Federal University of Campina Grande, in São Domingos - PB, Brazil. The treatments were arranged in a randomized block design, in a split-plot arrangement, with main plots consisting of four water deficit irrigation strategies based on phenological phases (without water stress - irrigation with 100% of crop evapotranspiration (ETc); water deficit (irrigation with 50% ETc) during the juvenile phase only; during the fruiting phase only; and during both the juvenile and the fruiting phases) and subplots consisting of two potassium doses (50% and 100% of the recommendation), with three replications and six plants per plot. Continuous water deficit during the juvenile and fruiting phases reduced stomatal conductance and transpiration, while deficit in the fruiting phase alone compromised the CO2 assimilation rate. Banana plants cultivated under water deficit in the juvenile phase with 50% K2O and in the juvenile/fruiting phases with 100% of the potassium recommendation showed the greatest physiological acclimation to water deficit conditions, although with yield losses compared to those irrigated with 100% ETc and fertilized with 100% K2O.