Water salinity and nitrogen fertilization in the production and quality of guava fruits

Abstract

Using nitrogen (N) to increase plant tolerance to salinity has been tested in many species. However, in addition to controversial results, most studies are conducted with annual species and/or in the initial growth stage and there are almost no studies with perennial fruit crops in the production stage. Thus, this study aimed to evaluate the production components and post-harvest quality of ‘Paluma’ guava irrigated with water of increasing salinity in soil fertilized with N. The experiment was carried out for two years in drainage lysimeters in an experimental area of the Federal University of Campina Grande (UFCG), Pombal, PB, Brazil. The experimental design was in randomized blocks, in 5 x 4 factorial scheme, with of  five levels of water salinity – ECw (NaCl) (0.3, 1.1, 1.9, 2.7 and 3.5 dS m^-1) and four N doses (ureia) (70, 100, 130 and 160% of the recommended dose - 541.1 mg of N dm^-3 of soil per year), with three replicates. Number of fruits, mean fruit weight, production per plant, polar and equatorial diameters of fruit and contents of soluble solids and ascorbic acid (vitamin C) decreased linearly with the increase in irrigation water salinity from 0.3 dS m^-1. The interaction between water salinity and N doses and the isolated action of N did not interfere statistically with the studied variables.