Abstract
The purpose of this study was to investigate the effects of ponding depth treatment on evapotranspiration in paddy fields. Three poding depth treatments, very sallow, shallow, and deep were used. The experimental plots were three $80m{\times}8m$ rectangular plots. Daily values of rainfall amount, ponding depth, irrigation water, drainage water, evapotranspiration, and infiltration were measured in the field. The ponding depth was continuously observed by observed nstaff during the growing season. The ET was measured by 1m diameter PVC lysimeters. Irrigation water volume was measured by 75 mm pipe flow-meters and the drainage water volume by 75 mm pipe flow-meters and a recording parshall flume. The results showed that irrigation water depths were 688.9 mm, 513.6 mm, and 624.4 mm in 2001, and 356.9 mm, 428.6 mm, and 513.2 mm in 2002 in very shallow, shallow, and deep ponding, respectively. The evapotranspiration were 465.0 mm, 484.1 mm, and 415.1 mm in 2001 and 461.3 mm, 476.3 mm, and 470.6 mm in 2002 in very shallow, shallow, and deep ponding, respectively.
