Soil moisture and its vertical transport were studied by use of observation data of soil water budget carried out at a grass field throughout one year.
(1) Bowen's ratio increases gradually with decreasing soil moisture near the surface when fine weather lasted for several days, but its seasonal increase towards winter is much more remarkable, independent of soil moisture. It is also shown, from the observed variation in soil moisture and ground water level, that soil moisture is discharged by evaporation only from the surface layer of soil in winter and through the deeper layers in summer. These results show that the activity of vegetation plays an essential role in evapotranspiration and soil moisture transfer.
(2) A theory with a simple model was developed from the viewpoint that the vertical transfer of moisture takes place in the vapor phase within the unsaturated layers of soil. The effect of soil moisture on the rate of evapotranspiration was discussed. A fundamental equation of vapor diffusion in soil layers was deduced, and the values of diffusivity and other constants were estimated. The effect of transpirating vegetation was considered as the moisture sink. Following results are obtained: the moisture change does not reach in winter the level of about 15cm depth within a dry spell for several days. The moisture in summer, on the whole, remains lower than that in winter down to about 20cm depth. The rate of evapotranspiration decreases gradually with decrease in surface soil moisture. Satisfactory agreement was obtained between observed and theoretical values. The observed facts may be explained by assuming that the moisture transfer in the soil layer near the surface takes place in the vapor phase.

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This paper describes the principle of calculating the degree hour and the fuel consumption for heating glasshouses under the occuring weather conditions. Formulas for the time change of air temperature in and out-side the glasshouse were used to determine the heating degree hour per day (D_h) from weather data. The relationship between D_h and ΔT was approximated by
Dh=5.9ΔT^1.22,
where ΔT=T_c-T_min, T_c is the desired air temperature in the glasshouse and T_min the outside minimum air temperature. By making use of the desired air temperature in the glasshouse of 5, 10 and 15°C, the total heating degree hour (k°C hr) over the cold season was calculated from the above formula and presented in Fig. 4. It is revealed from the geographical distribution that the absolute value of the degree hour is lower in the case of T_c=5°C than those in other cases. The relative difference in the degree hour between Kyushu and Hokkaido districts decreased with increment of the desired air temperature. The total degree hour was found to range between 1 and 25k°Chr in the case of T_c=5°C, between 5 and 40k°C hr in the case of T_c=10°C and between 10 and 60k°C hr in the case of T_c=15°C, respectively. The results presented in Fig. 5 shows the fuel consumption as a function of three of the heat loss ratio (R′), the degree hour (D_h) and the total heat transfer coefficient (H_T).

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The experiments presented here were carried out in an attempt to clarify the effects of shading and elapsed time after lodging on the photosynthesis in lodged plants during the ripening stage.
The flag leaves of normally standing (standard) and artificially lodged plants were subjected to ¹⁴CO₂ assimilation treatment for 1 hour under various light conditions at different time after heading.
The experimental results indicated that (1) the assimilated amount of ¹⁴C in the leaf decreased with decreasing light intensity irrespective of the lodging treatment, (2) the lodged plants showed lower amounts of the assimilated ¹⁴C in thier leaves than the standard plants under similar light condition, and (3) the lodged plants were also gradually disturbed in their photosynthesis with passage of time after lodging.
The hindrance of photosynthesis in the lodged plants is, therefore, enhanced by shading with their leaves and possibly by gradual decrease in chlorophyll contents in the leaves with passage of time after lodging. Factors affecting the photosynthesis in the logded plants were also discussed.

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When parallel light comes into foliage, a part of it is scattered by reflection and transmission of leaves. A foliage exposed to parallel light is divided into two parts: 1) sunlit part receiving both parallel and scattered light and 2) shaded part receiving only scattered light. Leaves of foliage were assumed to be inclined at a fixed angle (α) against the horizontal, and distributed at random as to leaf position and angle of leaf orientation (β).
The gross photosynthesis of a foliage (P_t) exposed only to parallel light with a constant angle of incidence (θ) was calculated by the author's method^{4, 5)}, for a horizontal-leaf (α=0°), an oblique-leaf (α=45°) and a vertical-leaf (α=90°) foliage (LAI=5 and 10). On the other hand, the gross photosynthesis of a foliage under isotropic light conditions (P) was calculated by using the equation given by MONSI and SAEKI⁶⁾, and the results were compared with P_t.
1) Mean gross photosynthesis p_d of sunlit part at F (cumulative leaf area index)=0.
When (π/2-θ)≥α, exposure of leaves to a parallel light in sunlit part is limited to adaxial leaf surface for any β value. When (π/2-θ)<α, the sunlit part is exposed adaxially in the range of β≤π/2+sin^-1 (cotα·cotθ), and abaxially in the range of β>π/2+sin^-1 (cotα cotθ). p_d was calculated as the average for β ranging from 0 to π.
θ-p_d relation was considered for fixed values of I_D (intensity of incident parallel light on a plane perpendicular to the rays).……The increment of θ decreases p_d when (π/2-θ)≥α, and increases p_d when (π/2-θ)<α. Furthermore, the θ-p_d relation was discussed also for the light condition where the value of I (horizontal intensity of incident parallel light) is kept at a fixed by varying the θ value according to the change of I_D as shown by I=I_D cosθ.
2) Relationships between θ and P_t under constant I_D.
When α=0°, the increment of θ diminishes the intensity of light received by leaves both in sunlit and shaded parts, and hence reduces P_t. When α=90°, however, P_t has its maximum at a certain value of θ which becomes somewhat small with increasing I_D and LAI. This variation of θ giving the maximum P_t depends theoretically upon the ratio in area between the sunlit and the shaded part and upon the photo-synthetic rate in each part. The decreasing tendency of P_t at α=45°with increment of θ is similar to that at α=0°in the θ range of 0°to about 30°, and similar to that at α=90°in the θ range of about 60°to 90°.
3) I(=I_Dcosθ)-P_t curves under constant I_D or under constant θ.
When α=0°, P_t is fixed for a constant value of I, even if I is given by any combination of I_D and θ. When α=45°and 90°, I-P_t curves under a constant value of I_D are different from those under a constant value of θ.
From these curves, θ-P_t relation was deduced for the light condition of fixed I values which are decided by changing the θ value according to the variation of I_D.

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