Investigations of the Relation between the Growth of Rice Plants and Their Surrounding Microclima (The First Report)

Abstract

The purpose of present study is to observe experimentally the relation between the growth of rice plants and their surrounding microclima. The observations were made in the rice fields at Harumati, near Hukuoka, which belong to the Department of Agriculture, Kyûsyû Imperial University.
The results obtained may be briefly summarrized as follows:-
(1) As is shown in Fig. 1. (a) (the mean temperature) and (b) (the relative humidity), the vertical distribution of the mean temperature and humidity varies from July to October. Throughout all months the humidity of air near the earth's surface shows a large percentage compared with that of the higher places. As to the mean temperature, however, it was not always so.
(2) For the purposes of studying the diurnal variation of mean temperature and humidity, special screens for self-recording thermograph and hygrometer were installed at the lower (30cm above the earth surface) and the higher places (120cm above).
The main feature of lower place was of higher humidity and lower temperature. (see Fig. 3 (a) and (b)). The time of occurrence of the maximum and minimum temperature nearly coincided at both levels. But the maximum of humidity at the lower place occured in the evening, while at the higher in the morning. On the other hand, the minimum humidity at both placesoccured in the same time.
(3) Moreover the vapour pressure and the amounts of evaporation at the lower and upper places were calculated.