Produção e qualidade da couve-flor com águas salobras em hidroponia

Abstract

The use of brackish waters for hydroponic cultivation of horticultural species in the semiarid region can ensure food production and improve regional quality of life. Thus, the interest arises to study the insertion of crops with high nutritional value, high market demand and that are adapted to local conditions, such as cauliflower, which has heat tolerant hybrid cultivars. Therefore, this study aimed to evaluate the water consumption, growth and quality of cauliflower production submitted to different levels of electrical conductivity of the nutrient solution in hydroponic conditions. Two experiments (Exp. I and II) were carried out in a randomized block design, with six replications. In the Exp. I, a 6 x 2 factorial arrangement in split-plot was used, which consisted of six levels of electrical conductivity of the time-weighted nutrient solution (ECsol 1.4, 2.6, 3.5, 4.6, 5.4 and 6.7 dS m-1), with three cauliflower cultivars (‘Piracicaba de Verão’, ‘Sabrina’ and ‘SF1758’) in the sub-plots, which were cultivated in the same hydroponic channel. Only cv. ‘SF1758’ in the Exp. II was cultivated, subjected to six levels of ECsol (1.4, 4.6, 6.7, 7.4, 9.1 and 11.2 dS m-1). Leaf area, plant height, stem diameter, number of leaves, fresh and dry matters of leaves, salinity tolerance, harvest precocity, inflorescence fresh matter, inflorescence diameter and height, water consumption, water use efficiency were evaluated in the Exp.I. In the Exp II the same variables were evaluated, except for salinity tolerance and harvest precocity. In the Exp. I, the water consumption, leaf area and inflorescence fresh matter were the variables most affected by the increase of ECsol. The water use efficiency of the leaf and inflorescence were not significantly affected influenced by ECsol, with means of 17.53 and 37.00 g L-1, respectively. The cv. ‘SF1758’ had higher salinity (dS m-1) tolerance threshold, while the cultivars ‘Piracicaba de Verão’ and ‘Sabrina’ were similar to each other. For Exp. II, all variables were significantly affected by ECsol, such as inflorescence fresh matter and water consumption, which decreased by 3.91 and 2.7% per unitary increase of CEsol, respectively. The water use efficiency fresh matter of leaves was not significantly affected by ECsol. Considering the dual purpose of cauliflower, salinity impaired leaf production any less than inflorescence.