Experimental studies were made on seasonal march and other behaviors of soil and water teniperature under vegetable cover through the whole growing season. The studies revealed the following characteristics on these-
(1) The daily minimum temperature of soil and water were independent of the state of vegetable cover but were dependent on the seasonal march of climate.
(2) On the contrary, the daily maximum temperature of soil and water was affected by both climate and the state of vegetable cover, and particularly by the latter.
(3) The daily amplitude of soil and water temperature was also affected by the state of vegetable cover and the relationship between the amplitude and the state of vegetable cover was given by the following equation:
φ=AP0/AB0=αe-βb+ (1-α)
here, AP0, AB0: amplitude of soil surface temperature with and without rice plant, respectively;L: leaf area index;α, β, : constants.
(4) The effect of vegetable cover (L. A. I.=6) affecting on the decrease of the amplitude was nearly equal to that of saturated soil having 13 cm depth.
