Adubação nitrogenada como atenuante da salinidade da água de irrigação em mudas de romã.

Abstract

The scarcity of good quality water is a limiting factor for irrigated agriculture, especially in semi-arid regions, and the use of water with high levels of salts, in this context, is an alternative to be considered. Thus, it is necessary to adopt appropriate agronomic strategies, among them, nitrogen fertilization, in order to guarantee the sustainability of the production system. Therefore, the objective of this work was to evaluate the tolerance of the pomegranate tree when submitted to nitrogen fertilization and irrigation with water of different saline levels. The work was carried out in a greenhouse belonging to the Center for Agrifood Sciences and Technology - CCTA of the Federal University of Campina Grande - UFCG. The design was in randomized blocks with a 5 × 5 factorial scheme with four replications, with the experimental plot consisting of three plants, whose treatments will be five levels of electrical conductivity of irrigation water (0.3; 1.8; 3.3; 4.8 and 6.3 dS m-1) and five doses of nitrogen (50; 75; 100; 125 and 150% of the recommendation), with the dose of 100% corresponding to 100 mg N per kg-1 of soil. Water salinity from 0.3 dS m-1 promotes a decrease in water relations, gas exchange and chloroplast pigment levels in pomegranates at 270 days after planting. Nitrogen doses did not attenuate the deleterious effects of saline stress on gas exchange and chlorophyll a content in pomegranate plants. Water salinity increases electrolyte leakage, regardless of nitrogen doses.