Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 1, 1999
Publication Date: N/A
Technical Abstract: Field corn (Zea mays L., hybrid Pioneer 3261) was grown using automatic drip irrigation controlled by a canopy temperature feedback algorithm in 1997 and 1999. The algorithm used threshold temperatures and times. If canopy temperature, measured every minute with an infrared thermometer, was above the threshold temperature for more than the threshold time, then an irrigation equal to peak consumptive use (10 mm) was applied. Threshold temperatures of 28 and 30 deg C were used. In mid-season, the mean canopy temperature for the 28 and 30 deg C treatments (three replicates) was separated by 2 deg C through most of the daylight hours. Yields of automatically-irrigated corn exceeded those of corn irrigated by replenishing the root zone to field capacity weekly according to neutron probe measurements of profile water content. In 1997, dry basis corn yields for automatically-irrigated corn ranged from 1.09 to 1.39 kg m**2 and those for weekly replenishment of soil water were significantly lower at 0.76 kg m**2. Results for 1999 will be compared with those for 1997.