Cultivo de alface em sistema hidropônico com solução nutritiva enriquecida com silício

Abstract

Hydroponic has been presented as a viable alternative to face the socio environmental problems of the Semiarid region. However, its high nutritional concentrations can damage the plants development. Silicon has been considered promising in increasing nutrient performance. Thus, it is understood that it is possible that its addition to the hydroponic nutrient solution promotes a better nutritional performance in lettuce plants. In this sense, this study aimed to evaluate the effect of silicon in nutrient solutions with low concentration of nitrate and different electrical conductivities, as a way to make the management of nutrients in hydroponic cultivation cheaper and enable a lower accumulation of nitrate in the lettuce crop. Therefore, two experiments were carried out in a completely randomized design, with split plots and under a 3x2 factorial scheme, where in the first one three electrical conductivities were evaluated (1.0 dSm-1; 2.0 dSm-1 and 3.0 dSm-1) and two silicon doses (0 and 0.4 mM), and in the second three potassium nitrate concentrations (0.05 M; 0.04 M and 0.03 M) and two silicon doses (0 and 0.4 mM) in NFT hydroponic culture of crisp lettuce cv. Veneranda. Morphological and biochemical characteristics and organic contents were evaluated, in addition to daily monitoring of pH, temperature and conductivity of the nutrient solution. The results were submitted to analysis of variance by the F test (5% probability), and the Tukey mean comparison test was applied, as well as the Shapiro-Wilk normality test, using the R® and Rstudio® software, Library package Expenses pt. Given the above, it was concluded that silicon enabled a better use of nitrate, but the reduction in its concentration caused a decrease in some analyzed variables. It is also possible to reduce the electrical conductivity of the nutrient solution to 1.0 dSm-1, and the use of silicon in the hydroponic cultivation of lettuce is advisable, however, further studies are needed that can evaluate different sources of silicon, as well as foliar application for the same purpose as the study.