Evapotranspiration Studies on Rice in Relation to Water Use Efficiency

STUDIES on evapotranspiration (ET) for rice were conducted in lysimeters and in the field. The daily ET varied from 3.6 to 10.9 mm/day for a spring crop, from 3.3 to 11.7 mm/day for a summer crop, and from 1.8 to 7.6 mm/day for a fall crop. The mean daily ET values were 6.5, 6.8 and 4.5 mm/day for spring, summer, and fall crops, respectively. Total ET varied from 740 to 880 mm, 610 to 840 mm, and 400 to 500 mm for spring, sum-mer, and fall crops, respectively. The mean total ET values were 800, 740 and 450 mm for spring, summer, and fall crops, respectively. From 759 to 1150 kg with a mean of 875 kg of water was required to produce 1 kg of rough rice grain.