Estratégias de irrigação com água salina e ácido ascórbico no desempenho agronômico e goiabeira enxertada.

Abstract

Prolonged periods of drought in the Brazilian semi-arid region have driven the use of water with high salt content to meet the water needs of agricultural crops. This practice has led to the search for strategies to mitigate the adverse effects of salinity on plants, ranging from identifying the susceptibility of different phenological phases to the application of elicitors, such as ascorbic acid. Therefore, this study aimed to evaluate the physiology, growth, and fruit production of guava cv. Paluma under irrigation strategies with saline water and foliar application of ascorbic acid in the semi-arid conditions of Paraíba. The experiment was conducted in pots adapted to drainage lysimeters, with a capacity of 100 L, under field conditions at the Experimental Farm belonging to the Center for Agricultural and Food Technology Sciences (CCTA) of the Federal University of Campina Grande (UFCG), in São Domingos, Paraíba. The experimental design used was a randomized block design in a split-plot arrangement, with the main plots consisting of four irrigation strategies using saline water (irrigation with low electrical conductivity water, 0.9 dS m-1 , throughout the cycle - SE; irrigation with high salinity water, 3.3 dS m-1 , only during the vegetative phase - VE; flowering phase - FL; fruiting phase - FR), the subplot consisted of three concentrations of ascorbic acid (0, 200, and 400 mg/L), with three replications and one plant per experimental unit. The irrigation strategies with 3.3 dS m-1 water did not negatively affect the photosynthetic activity, growth, and production of the guava tree. Irrigation with 3.3 dS m-1 water during the flowering phase resulted in a greater number of fruits and production per guava plant. The application of 200 and 400 mg/L of ascorbic acid increased the photosynthetic activity of guava plants under a saline irrigation strategy 324 days after transplanting. Foliar application of ascorbic acid at a concentration of 400 mg/L promotes beneficial effects on the production components of guava plants in the period of 380-420 days after transplanting.