Evapotranspiration and crop coefficient for Radish under protected cultivation

The objective of this study was to evaluate the real crop evapotranspiration and radish crop coefficient, “Crimson Gigante” cultivar, for different phenological stages under protected cultivation. The research was performed from March to April 2015 in pots arranged in greenhouse located at the Federal University of Campina Grande (UFCG). Dripping irrigation system was used for plants irrigation and the management was based on reference evapotranspiration (ET0). The water efficiency application of irrigation system (Ea), gross irrigation depth (LB), real crop evapotranspiration (ETr) and crop coefficient (kc) were determined during radish cycle cultivation. The results showed Ea = 89,30%, average daily LB of 4.31 mm, accumulated values of ETo and ETr of 175 and 150 mm. The maximum kc (0.94) was obtained in the intermediate phenological stage (III) and the minimum kc (0.58) occurred in the final stage (IV) with ETr of 75.4 and 14.5 mm, respectively. The crop coefficients were similar to those in the literature, except in the last growth plant stage. The increase in leaf area can be used as a parameter to estimate the water consumption of radish plants. Key words: Crimson Gigante, greenhouse, water consumption.