Manejo da irrigação com o programa computacional irrigauto e efeito de doses de potássio na qualidade de frutos da melancia

Abstract

The quantity of water and fertilizer allied to the cultural dealings influence the quality of the fruits. The use of software and equipment working together is an alternative capable of improving quality indicators. The objective of this work was to use the irrigation software “irrigauto” as a tool to perform irrigation monitoring and to verify potassium dose effect as watermelon fruits. The experimental design was a completely randomized design in subdivided plots, 4x5 scheme, referring to 4 irrigation depht (3mm, 6mm, 9mm and 12mm) and 5 doses of fertilization K2O (A1 90kg K2O, A2 120kg K2O, A3 135kg K2O, A4 150kg K2O, A5 180kg K2O/ ha), with three replicates per experimental unit, totaling 60 plants in the experiment. The experiment was conducted in the experimental area of the Laboratory of Hydraulics and Irrigation of the Department of Agricultural Engineering - UFC, from October 2014 to January 2015. In irrigation monitoring it was analyzed the operation of: capacitive sensor set with remote module and soil moisture and the variables: fruit mass (MF), transverse diameter (DT), longitudinal diameter (DL), soluble solids (SS), titratable acidity (TA), SS and AT ratio, pH, Luminosity (L *), Chroma (C) and Hue angle (H). The capacitive sensor and remote module were used to set up irrigation monitoring efficiently, generating moisture graphs. The capacitive sensors had different behaviors among themselves. The variables MF, DT, DL, LP and CP were significantly influenced by the factors L (L), fertilization (A) and the interaction (L x A). The values of SS and Hue angle of the pulp was influenced by fertilization and the interaction (L x A). The AT and SS / AT received influence of the depht and of the interaction (L x A). The brightness and angle Hue of the light green stripe of the watermelon peel received influence of the depht factor. The luminosity of the dark green stripe of the watermelon peel was influenced by the interaction (L x A). The other variables did not show a significant influence of the factors of production. The dose of 114 kg ha-1 K2O with the 6 mm depht was the combination that most influenced the quality of the fruits. In this way, one can be conclude that the use of the software “irrigauto” in conjunction with the capacitive sensor and remote modules can be used for irrigation management. The interaction between irrigation depth and fertilization made it possible to know the significant responses for the analyzed variables in the quality of watermelon fruits.