Incoming Radiation and Transpiration at the Air-Conditioned Glasshouse

[摘要] As the surface temperatures of roof glass, plant leaf, bed etc. have been proved to be almost the same by the survery in an air-conditioned glasshouse, we can simplify the heat balance equation of leaf layer omitting the long wave terms from it. LE=(L+β)Si↓al+C By measuring, therefore, the transpiration (LE) and the radiation (Si↓), the coefficient of short wave absorption (al) and the heat conductance (C) of the tobacco leaves are obtained directly at the same time. Experimental results show that on a fine day; al=0.55, C=-4.6 cal/cm2·hr, mean value in half a year; al=0.38 and C=57.4 cal/cm2·day respectively. The author have calculated the heat balance of the leaf layer in summer using these values: the total radiant energy into the leaf layer is distributed 60 per cent to re-radiation, 4 per cent to heat conductance and residual 27 per cent to transpiration respectively. The results of trial calculation using these measured values agree considerably well with the water supply in every month in two rooms of the air-conditioned glasshouse. (fig. 8).

[学科分类] 农业科学（综合）