On the Evapotranspiration from Paddy Fields in a Southern Part of Kyushu

Abstract

Results of observations on evapotranspiration in both early seasonal cultivation and ordinary cultivation systems for four years (1960 to 1963) are presented. Mean daily totals of evapotranspiration in both cultivation systems were nearly the same, but the extreme of daily total in evapotranspiration in early cultivation exceeded that in the ordinary cultivation. The difference in extremes arises from the fact that the period with dense plant canopy in the early cultivation coincides with the period of most intensive insolation in year.
Evaporation from an ordinary small pan was found to agree fairly well with evapotranspiration from paddy fields and to be used as a rough measure of it. The heat balance and the combination methods were applied to estimating the evapotranspiration. The latter was found to be more promising than the former for operational use.