Irrigação com águas salinas e doses de nitrogênio no cultivo de mudas de maracujazeiro ‘BRS RC’.

Abstract

In fruit growing, the purple passion fruit has aroused the interest of producers, due to its high commercial value, being produced mainly for export, where the high saline levels of the water used for irrigation in the Northeast region, compromises growth and production, making it necessary to adopt management techniques, such as the use of nitrogen fertilizer, capable of attenuating the effects of salts on plants. In this context, the objective was to evaluate the growth, physiological indices and seedling quality of the purple passion fruit, grown under different levels of irrigation water salinity and nitrogen doses. The experiment was carried out at the Federal University of Campina Grande - UFCG, Pombal - PB, in a greenhouse environment, using a randomized block design, in a 5 x 4 factorial scheme, whose treatments were testing five levels of electrical conductivity irrigation water (0,3; 1,1; 1,9; 2,7 and 3,5 dS m-1) associated with four nitrogen doses (50%, 75%, 100% and 125% according to recommendation), with four replications and three plants per plot, totalizing 240 experimental units. The salinity of the irrigation water above 0,3 dS m-1 compromised the leaf area, the dry stem mass, the relative water content and the leaf succulence of the purple passion fruit 'BRS Rubi do Cerrado'. High doses of nitrogen potentiated the deleterious effects of irrigation water salinity on stomatal conductance, transpiration, internal CO2 concentration, CO2 assimilation rate, number of leaves, stem diameter, plant height, root/shoot ratio and deficit of water saturation of the purple passion fruit. From an agronomic point of view, purple passion fruit seedlings 'BRS Rubi do Cerrado' are considered quality when irrigated with salinity water up to 3,5 dS m-1.