The three elements of water-loss in the paddy field-evaporation from water surface, transpiration from the rice plants and percolation to the depth of ground were measured. The results obtained are given in Tables 1-3 and Fig. 2.
Evaporation from water surface in the paddy field gradually decreased with the lapse of growing time and became almost constant after late August.
Transpiration increased with the lapse of growing time, and showed two peaks in the cultivating term. The first peak is at the ear-developing stage (late August) and the second at the early stage of ripening (late September).
Percolation was great in midsummer with continuous clear weather, and exudation was great in rainny season (BAIU and early autumn). The great percolation or exudation depend on the characters of the local topography, soil structure, and underground water level.
