Efeito da cor do perfil na temperatura e concentração de oxigênio da solução nutritiva em cultivo hidropônico de rúcula

Abstract

This study has as main purpose to evaluate the influence of different color profiles on the cultivation related to temperature and dissolved oxygen concentration in the nutrient solution in the growing of rocket over two growing seasons in hydroponic system NFT. The experiment was conducted in the period of April to August 2012, in protected ambient counting with three production benches each comprised of eight profiles for the conduct of the plants evaluated, having four black and four white painted with plastic paint. The two colors of profile were arranged alternately and, to surround effect, a profile was installed on each edge of the bench. During the experiment, the temperature was recorded and the concentration of dissolved oxygen in the nutrient solution in the profiles three times per day, at 9:00, 15:00 and 21:00. In each reading recorded the temperature and concentration of oxygen at the beginning and end of two profiles of each color. For growth analysis, assessments were performed every four days in two growing seasons, autumn and winter, and the variables were evaluated: leaf dry matter, stem dry mass and root dry mass; plant height; root length; number of leaves and leaf area index. The results were analyzed separately and show that the different colors and profile stations modify the temperature and oxygen concentration of the nutrient solution. The black color profile increased the temperature of the circulating nutrient solution. Changes in temperature affected the concentration of dissolved oxygen in the nutrient solution. The different colors and seasons interfered with the growth of rocket. Plants grown in white profile showed higher leaf dry matter, stem dry mass and root dry mass, as well as increased root length and increased leaf area index.