MONITORING WATER-STRESS IN CORN WITH AN I NFRARED THERMOMETER

An experiment was conducted in 1986 at the field laboratory belonging to CPATSA/EMBRAPA to study the response of corn crop subjected to four different levels of irrigation (100%, 75%, 50% and 25% of field capac ity). The objective was to verify the possibility of monitoring the wa ter stress in corn (Zea mays L.) using the technique of infrared therm ometry. The experimental design consisted of a randomized block design with four irrigation treatments and three replications. Each experime ntal unit occupied an area of 76.8 m(2). The irrigation system consist ed of furrows blocked at the extremities, and the volume of irrigated water was controlled by means of a water meter. The irrigation treatme nts were strated 30 days after planting. The data utilized in the pres ent work were collected along the whole life cycle of the crop. The in dices of Stress Degree Day, Temperature Stress Day and Canopy Temperat ure Variability were utilized for monitoring the water stress.