Production and quality of purple kohlrabi under nutrient solutions of different electrical conductivities¹

Produção e qualidade de couve-rábano roxa sob soluções nutritivas de diferentes condutividades elétricas

HIGHLIGHTS:

Kohlrabi is sensitive to electrical conductivity of the nutrient solution greater than 1.31 dS m^-1.

Vitamin C content in kohlrabi increases with salt stress provoked by nutrient solutions between 2.3 and 2.9 dS m^-1.

Bulb is the part of the kohlrabi plant most affected by salinity of 3.75 dS m^-1.

ABSTRACT

Managing electrical conductivity levels is one of the fundamentals required to obtain greater production and better quality of vegetables. The aim of this study was to evaluate the effect of electrical conductivity of the nutrient solution on the kohlrabi crop cultivated in semi-hydroponic system. A randomized block design was used with five treatments associated with the electrical conductivity of the nutrient solution (1.31, 1.71, 2.37, 2.98, and 3.75 dS m^-1) and four replications. The plants were harvested 78 days after transplanting and evaluated for growth, production, and postharvest quality. Nutrient solution with electrical conductivity (EC) of 1.31 dS m^-1 promotes greater production of purple kohlrabi. The increase in EC reduced linearly most of the analyzed variables (leaf area, fresh mass of leaves, bulb and shoot, dry mass of leaves and total, bulb volume and firmness), with more significant losses for the bulb fresh mass (50.54%) and bulb volume (57.37%) variables. The use of nutrient solution with EC between 2.3 and 2.9 dS m^-1 increased the vitamin C content and the titratable acidity.

Key words:
Brassica oleracea Gongylodes Group; mineral nutrition; hydroponic cultivation