EVALUATION OF THE CROP WATER STRESS INDEX ON SIX CORN LINES

Abstract

In order to determine the potential use of the infrared thermometers to estimate the crop water stress index (CWSI) instead of another techniques which are more time and labor consuming, two models of CWSI were evaluated in six lines of corn (Zea mays L.). These lines were grown on three different soil water potentials (0.03, 0.8, and 1.5 MPa); at each of these water potentials, the canopy temperature was measured using an infrared thermometer and the soil moisture availability was determined by the gravimetric method. At the end of the crop season, the grain yield of each line of corn was obtained. The results of this study showed that the two models gave a good agreement between the value of the index and the magnitude of the crop water stress (R2 varied from 0.79 to 0.86), so it is possible to estimate the soil moisture availability by measuring the difference between the canopy and the air temperature. An inverse relation between crop yield and the value of the CWSI for each line was also found (average R2 = 0.60).