INFRARED THERMOGRAPHY FOR DETERMINING TRAY TEMPERATURE IN LETTUCE PRODUCTION

This research was carried out in Recife, PE, Brazil, and aimed to assess the variation of the surface temperature of trays and substrate in the production of lettuce seedlings and its influence on the final product. Trays consisted of expanded polystyrene, conventional polyvinyl chloride, polyvinyl chloride painted white, and polyvinyl chloride painted gray. Two cultivars (Solaris and Vanda) were used to register crop biometric variables from seedling stage to the final product (46 days). Tray and substrate temperatures were recorded by means of an infrared thermal imager. The experimental design was a completely randomized design in a 4 x 2 factorial scheme with three replications. The conventional polyvinyl chloride tray presented the highest surface temperature. The substrate temperature in the styrofoam tray was higher when compared to the others. The white tray showed the lowest values of substrate temperature, providing a better seedling development. Seedling quality and the most important agronomic characteristics for commercialization were obtained in the white tray, being the best alternative for lettuce cultivation.