Electrical conductivity of nutrient solution on crisphead lettuce fertigated at sand

Nutrient solution aspects such as the electrical conductivity are extremely important in hydroponic systems, with few studies related to that being performed in fertigation of crisphead lettuce at substrates. The aim of this work was to evaluate nutritional and productive aspects of crisphead lettuce, cv. Mauren, submitted to electrical conductivities of nutrient solution fertigated in pots with sand. The experiment was carried out in a greenhouse at the Agrarian Sciences Center of the Londrina State University (UEL), Londrina, PR, using a randomized block design with five treatments (0,8; 1,3; 1,8; 2,3 and 2,8 dS m-1 at nutrient solution) and five replications. It was evaluated the total mass of fresh matter (TMFM) and the total mass of dry matter (TMDM) of shoots, as well as the concentrations of macronutrients. The data were submitted to ANOVA and, when significant, were adjusted to regression models. The increase of the electrical conductivity at nutrient solution did not influence both TMFM and TMDM, providing response only for phosphorus (quadratic) and potassium (positive linear) concentration at shoots, which were, as the other nutrients, near to the sufficiency range.