The mass thickness and the moisture ratio of various plant leaves were measured with the beta radiation transmission method using a G-M detector and ¹⁴C source.
Since beta rays transmitted by leaf are diffuse, the placement of the detector with respect to the leaf was a primary limiting factor on the transmitted beta rays that would be detected. It was recognized that the distance between leaf and detector or source, should be kept as short as possible.
The transmission of beta rays decreased with increasing mass thickness of a leaf. The mass thickness of the leaf made the mass absorption coefficient almost independent of the nature of the leaf.
Although the absorption curve was not linear under a wide range of the mass thickness, the curve was approximately linear for thin leaves.
The low-energy beta ray source, such as ¹⁴C, is to be used only for thin leaves of mass thickness smaller than 20mg/cm². On the contrary, the high-energy beta ray source, such as ²⁰⁴Tl, should be used for thick leaves of mass thickness larger than 30mg/cm².

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The canopy photosynthesis and the CO₂ environment within a crop canopy are studied numerically by employing the model based on transfer equation of CO₂ within the canopy. The transfer of CO₂ can be expressed by
-d/dz(KdC/dz)=-f_L(z)p(z)+f_L(z)rp,
where p(z) is CO₂ uptake intensity of leaves, r_p respiration intensity of leaves, f_L(z) leaf area density function, K transfer coefficient and C concentration of CO₂ in the air. Numerical computations were made on an electric computer (Tosbac 3400) to give profiles of CO₂ concentration and cumulative CO₂ flux profiles. Iterative formulae (5) and (6) were used for numerical integration of the transfer equation of CO₂. The following relations are assumed
p=D_{c, max}⋅C(Q/a+Q),
r_p=const=αp_∞,
K=K_H-δ(H-z),
Q=Q_Hk/1-τexp{-k∫^H_zf_L(z′)dz′},
where D_{c, max} is the effective exchange velocity for CO₂ exchange between ambient air and photosynthetic action center in leaves under sufficiently high light intensity, Q intensity of short-wave radiation on leaves, K_H transfer coefficient at the canopy top (z=H), Q_H intensity of short-wave radiation at the canopy top, k extinction coefficient, τ, transmissibility of leaves for short-wave radiation and a, α and δ proportionality constants. The boundary conditions used in the computations are expressed by Eq. (4).
1. CO₂ profiles within a model canopy are presented in Fig. 1. The top half of Fig. 1 shows CO₂ profiles within the canopy (LAI=F_t=4.0) as a function of radiation intensity and transfer coefficient. The CO₂ profiles as influenced by the soil CO₂ flux are shown in the bottom half of Fig. 1. In the case of low transfer coefficient and high intensity of short-wave radiation, CO₂ concentration profiles are characterized by a minimum in the middle layer of the canopy. The minimum value droppes to 41⋅10^-8g CO₂/cm³ (i.e. down to 74 per cent of the normal concentration). A similar drop of CO₂ concentration was also observed in a corn canopy on calm and sunny days. The height (z_m) of the minimum concentration moves towards the canopy top with decreasing radiation intensity (see Fig. 2). The dependence of the height z_m on radiation intensity was well approximated by an exponential formula.
2. Fig. 3 shows that the daily range of CO₂ concentration decreases rapidly with increasing wind velocity and approaches about 10ppm with wind velocity of about 6m/sec. A similar conclusion was reached in a slightly different approach to the problems (UCHIJIMA et al. 1967). The relation between the daily range of CO₂ concentration at the canopy top and the leaf area index was well fitted to a rectangular hyperbolic equation (Eq. 4). Increase of the extinction coefficient and the transfer coefficient leads to decrease in the maximum daily range of CO₂ concentration at the canopy top. The daily range of CO₂ concentration within the canopy increased gradually with the canopy depth.
3. Fig. 8 gives profiles of cumulative flux of CO₂ in the canopy in relation to the canopy denseness, radiation intensity and extinction coefficient. The profiles presented hear are of the same general patterns as those determined experimentally in a corn canopy (INOUE et al. 1968).

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This paper presents the method of long-range forecasting about drought damages of rice crops.
The method is as follows;
(1) The Lag-correlation coefficients between precipitation and temperature in summer and monthly mean 500mb height in winter are calculated at 198 points on the dorthern hemisphere, (fig. 3).
(2) The number of information is calculated by the correlation coefficients of 1584 points and data of 500mb height in 1955-1967 (Table 2).
(3) The correlation coefficient between the ratio of drought damage of rice crop and the information's number about precipitation and temperature is calculated.
(4) Mean square regression plane is derived.
The results show that the multiple correlation coefficient between the rate of drought damages of rice crops in Fukuoka Prefecture and the information's number about precipitation and temperature by 500mb height in January was +0.83. This value is significant.
This paper describes that the correlation field for droughts in west Japan resemble the correlation field for cold summer in north Japan. It is possible to forecats the drought damage of rice crops in summer from winter values of 500mb height.

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A computation of the evaporation in meso scale areas, Kyushu Island and Setouchi district, by means of atmosheric water vapor budget has been tried using radiosonde observations. The calculation scheme for this analysis is introduced at chapt. 2, and the discussion on errors in such numerical analysis is described at chapt. 6.
1) It is useful even over the meso-scale area to estimate the evaporation with the method of water-vapor budget analysis.
2) It is better to take a short air column (from earth's surface to 850mb) to eliminate the influence of precipitation R and the transfer of liquid or solid water.
3) The calculation method by means of Electronic computer on the assumption that each meteorological quantity varies linearly between two adjacent stations is also available.
4) Evaporation has large values in the field of water vapor divergence and small values, in the field of water vapor convergence and when the storage of water vapor within the atmospheric column, ∫(∂q/∂t) (dp/g) shows high negative values.
5) Seasonal variation of the calculated E from both the areas follows closely the Thornthwaite's Potential Evaporation (PE) during January to August in (except Aprill), and each of E_s in this duration, 653mm (Kyushu area), 539mm (Setouchi area) is quite close to PE's 607mm.
6) Evaporation seems to have relatively high values in drought seasons.
7) Evaporations caluclated with the data of two soundings at 09 and 21 JST give different values and those at 21 JST have always larger values than the values at 09 JST.

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