Remotely-sensed canopy temperatures used for irrigation timing linked to crop water stress index (CWSI)

We used the canopy and air temperature differential to calculate the Crop Water Stress Index (CWSI) of maize at Keszthely, Hungary over the past fourteen years. Our objective was twofold. First, we wanted to. determine if: the.CWSI could be used to determine when irrigation water should be applied to maize under Hungarian weather conditions. Second, we wanted to know what influence N had on the CWSI. The experiment included two levels of N fertilization and three water treatments: fully watered treatment, irrigated treatment, and. non-irrigated control. Canopy temperatures were measured using an infrared thermometer. Relevant meteorological and plant data were also collected. We concluded that during humid years, there is no need to irrigate maize in Hungary. In hot, dry years the CWSI is a useful tool for determining irrigation timing. The amount of applied nitrogen seemed to be a basic determinant of canopy temperature. Additional research needs to be done to learn more about the effect of stressors such as disease, or plant nutrition on, the CWSI.