The present experiment is a part of studies as for the quantity of irrigating water for the rice field in the warmer district of Kyushu.
The results shown in Table 2 are the typical, values on a clear day at the maximum tillering stage of rice.
1) The absorption of water by the plant is vigorous in the forenoon, decreases rapiddly in the afternoon, and almost ceases in the early night. It recovers gradually in the dead of night.
2) The evaporation from water-surface in the field is about 45% of that measured with the evaporation-gauge of “Japanease Meteorological Observatory Type.”
3) The percolation is dependent on the topography, sort of soil, climate and the depth of groundwater-surface.
Much attention should be paid as for the percolation, for it is very large and variable in each locality.