Estratégias de uso da água salobra para cultivo de mostarda em sistema hidropônico

Abstract

Arid and semi-arid regions have limited availability of surface water, with groundwater as an alternative, often with high concentrations of salts. When used in irrigation, these waters can cause disturbances in biochemical and physiological processes and growth in cultivated plants, which consequently reduces their production. Hydroponics is a technique that allows the efficient use of brackish water without major losses in agricultural production. Therefore, the objective of this study was to evaluate two strategies for using brackish water in two mustard cultivars 'Lisa da Florida' and 'Crespa' in an laminar slow technique hydroponic system (NFT). A completely randomized experimental design was used in a factorial scheme 3 (three levels of electrical conductivity of water (ECw) – 0.3; 2.5 and 4.5 dS m-1) × 2 (two strategies for using brackish water – exclusive use and only for preparing the nutrient solution), with three repetitions. The fresh and dry mass of the aerial part, dry mass of the root, plant height, number, length and width of the leaf, contents of organic solutes (soluble carbohydrates, free amino acids, soluble proteins and free proline), inorganic solutes (Na+, K+ and Cl-) and chlorophyll contents (chlorophyll a, b and total) were evaluated. According to the results presented in Chapter II, both cultivars are viable for the hydroponic cultivation 'Lisa da Florida' mustard up to ECw 4.5 dS m-1 independent of stategy of uso, while 'Crespa' mustard is sensitive to salinity, being preferable use of brackish water only for the preparation of the nutrient solution.