DESEMPENHO DE RÚCULA SUBMETIDA A FREQUÊNCIAS DE IRRIGAÇÃO E DOSES DE HIDROGEL

Abstract

The new technologies in agriculture associated with the use of water-retaining polymers have proved to be a new research tool in irrigation management. Its use has shown to be promising; however, there are few studies showing details on the dosage to be applied and on promoting water saving. Therefore, this study aimed to find out the effect of the use of hydrogel at different doses and irrigation frequencies on the arugula development and productivity as well as its physiological responses. The experiment was carried out in a farm-school’s experimental field of Evangelical College of Goianésia in the countryside protected environment, at GO-230 highway 1 km away from the right of the Boa Vista Sector, Goianésia City, Goiás State, (GO), Brazil. The experimental design was in 2 x 2 x 4 splitplots comprising sixteen treatments with four replicates, totaling sixty-four plots, each plot working as a block for the subplot treatments. The plots received frequencies F1 (once a day) and F2 (one day interval). The splitplots were shared on Factor A [cultivars V1 arugula Michaella and V2 arugula Donatella (both with broad leaves)] and Factor B [hydrogel doses (0, 1.0, 1.5, 2.0 g kg-1 of substrate)] in each pot containing 5 kg of substrate. Before harvesting, the chlorophyll index was noted with the Soil Plant Analysis Development (SPAD). The harvest was carried out forty-five days after sowing, when the plants reached their maximum vegetative growth. All the plants in the experiment were harvested. Immediately after harvesting, the following analyzes were carried out: (a) maximum plant height (H) measure, with a ruler graduated in mm; (b) number of leaves per plant (NL) per count; (c) aerial part fresh mass (APFM) with a digital scale with a precision of 0.01 g and determined by the average production of each plant in the pot; (d) aerial part dry mass (APDM), with a digital scale with a precision of 0.01 g; (e) productivity (PRO), extrapolating the APFM results (55,000 plants/ha-1); and (f) efficiency in using water (EUA), determined as a function of productivity. The data were submitted to regression analysis by Analysis of variance (ANOVA), defining the best fit at 1% or 5% significance level of probability by the SISVAR 5.6 statistical software. It was concluded that the hydrogel doses showed no statistical difference; however, it showed a positive influence on the variables under study. The arugula Donatella cultivar showed superior behavior in relation to Michaella cultivar. Irrigation had an isolated effect on arugula inside the variables used.