NÍVEIS DE IRRIGAÇÃO E USO DE HIDRORREDENTOR NA PRODUÇÃO DE ALFACE EM AMBIENTE PROTEGIDO

Abstract

The use of hydrogels at irrigated agriculture has being promising, fact observed in literature; however, other studies should be done, because there are no effective methodologies about the use of these substances. Therefore, this study aims to evaluate the effect in different irrigation levels and different doses of hydro retainer solution on lettuce production in protected environment. The experiment was carried out in the experimental area of the Vegetable Crops of Goiano Federal Institute, Urutaí Campus, state of Goiás, (GO), Brazil. The experiment was carried out from December 2017 to January 2018 under protected environment. The experimental design was in randomized complete block in a 4x5 factorial scheme of split-plot and four blocks, four irrigation levels (50%, 75%, 100%, and 125%) obtained from the daily evaporation by the hook micrometer and five doses of hydrogel solution (0, 50, 100, 150, and 200 g). Each dose (split-plot) had the equivalent of sixteen plants, and only four plants were considered useful for analyzes. In the experiment, the following arrangement was made: (a) each split-plot was composed by 16 plants; (b) each plot was composed by 80 plants; and (c) each block was composed by 320 plants, totaling 1280 plants. Vanda was the crisp lettuce cultivar used. Harvesting xiv was carried out at the twenty-ninth days after transplant, and the fresh mass from the aerial part, dry mass from the aerial part, maximum plant height, number of leaves, productivity, and efficient use of water were the variables analyzed. Data was collected by analysis of variance, and significant results were obtained by regression analysis performed by exploratory pre-analysis of data. In accordance with results from the average found, there is an increase in the percentage of soil gravimetric moisture, both in the increase of the dose of hydro retainer solution and in the increase of the irrigation level. The use of hydro retainer solution on crisp lettuce, Vanda cultivar, provided a significant increase in each evaluated productive parameter. The irrigation levels used had a significant influence on fresh mass from aerial part, maximum plant height, productivity, and efficient use of water. The productivity increased 18.42% in the irrigation levels used, and the highest estimated values were presented in the dose of 157.49 g (14.46 t.ha-1 ) hydro retainer solution.