Crescimento, produção e qualidade da couve-flor e hidroponia com uso de águas salobras

Abstract

Drilled wells are often the only source of water for isolated rural communities in the Brazilian semi-arid region, but their quality is often compromised by the high concentration of salts, thus limiting the use of these waters for irrigation of various plant species in conventional soil cultivation. Given the above, the aim of this study was to evaluate the vegetative and productive development of cauliflower in NFT hydroponic cultivation as an alternative to the use of brackish water. The experiment was carried out in a greenhouse, being designed in randomized blocks with six replications, with the cauliflower plants subjected to six levels of electrical conductivity of water - ECa. The ECa levels adopted were 1.5; 2.5; 3.5; 4.5 and 5.5 dS m-1 obtained by adding NaCl to the supply water (ECa 0.3 dS m-1 - control). The waters were used for the preparation of the nutrient solution, while for the replacement of the water consumption of the plants, only supply water was used. The cultivar used was 'SF1758', spaced 0.80 x 0.50 m between hydroponic channels and plants, respectively. Plant height, length and width of the leaf blade and number of leaves were evaluated at 15, 25, 35 DAT. At the time of harvest, stem diameter was also evaluated; fresh mass of leaves and stem; diameter, length and fresh mass of the inflorescence. From the previous measurements, the DI/CI and CLF/LLF ratios were calculated, as well as the area of the leaf blade and the fresh and dry mass of the aerial part. Among the growth variables analyzed, except NF and the CLF/LLF ratio, they were not affected by the increase in ECa at harvest time, while only plant height was affected by salinity at 35 DAT. For the productive variables, the fresh mass of the inflorescence and the diameter of the inflorescence were reduced with the addition of ECa. The hydroponic cultivation of cauliflower in a hydroponic system with brackish water is possible, although with reduced production.