Potassium fertigation reduces salt stress in okra cultivated in a protected environment

Resumo

The use of saline water in the production of vegetables should be performed together with a strategy to inhibit salt stress. The objective of this study was to analyze the effect of potassium supplementation as a salinity-attenuating agent in okra. The experiment was conducted in a greenhouse at the Federal Rural University of the Semi-Arid Region, in Mossoró, RN, Brazil. The experimental design was completely randomized, in 2x5 factorial scheme with 4 replicates. Two okra cultivars (Santa Cruz 47 and Valença) fertigated with five fertigation managements [F1= irrigation with non-saline water (0.55 dS m^-1) and fertigation with a standard dose of potassium (6.004,4 mg plant^-1); F2, F3, F4 and F5= irrigation with saline water (3.5 dS m^-1) and fertigation with increasing doses of potassium (6, 9, 12 and 15 g plant^-1, respectively)]. Plants were collected at 110 days after emergence and evaluated for growth variables (leaf number, leaf área, leaf dry mass, stem dry mass, stem dry fruit and total) and yield (fruit number, average fruit mass and fruit production). The potassium influence the growth and yield characteristics of okra irrigated with saline water. The highest yields of fruits occurred at doses of 9.56 and 10.23 g plant^-1 of K, being 330.24 and 733.36 g plant^-1, in cultivars Santa Cruz 47 and Valença, respectively. Okra irrigated with saline water is more demanding in potassium.