Lettuce growing in different hydroponic systems and nutrient concentrations of the nutrient solution¹

Cultivo de alface em diferentes sistemas hidropônicos e concentrações de nutrientes na solução nutritiva

ABSTRACT

Alternative techniques for cultivation without soil are widespread; however, studies comparing hydroponic systems still need to be studied, mainly in semi-arid regions. The present study aimed to evaluate the effect of hydroponic systems on the yield and quality of lettuce cultivars subjected to different electrical conductivities of the nutrient solution. The research was conducted in a greenhouse, adopting a completely randomized design in a 2 × 2 × 3 factorial scheme, being two lettuce cultivars (Cinderela and Rubinela), two electrical conductivities (2.90 and 1.6 dS m^-1), and three hydroponics systems (NFT, semi-hydroponic, and floating), with three replications. The number of leaves, leaf succulence, specific leaf area, leaf fresh mass, total dry mass, leaf area, titratable acidity, vitamin C, and soluble solids were evaluated. Cinderela cultivar showed the highest average leaf fresh mass, total dry mass, leaf area, and vitamin C values. The NFT and floating systems provided the highest leaf yield and quality, especially in the solution of 1.60 dS m^-1. The semi-hydroponic system provided greater development of the plants with a more concentrated nutrient solution (2.90 dS m^-1).

Key words:
electrical conductivity; vegetables; Lactuca sativa

HIGHLIGHTS:

Cultivation systems and nutrient solutions influence lettuce plants.

NFT system provides greater plant biomass in a less dilute solution.

Diluted nutrient solution with lower EC (1.6 dS m^-1) is sufficient for lettuce production and quality.