水稲の登熟過程における生産に有効な気候資源量を表わす指標として気候登熟量示数を先に発表したが, 本報では平年気候下におけるこの示数の我国における地域性について若干の考察を行なつた。
(1) 出穂期別登熟量示数の地理的分布を調べた結果, 8月前半の早い出穂期の場合は東日本の示数が大きく, 東日本の中では太平洋側より日本海側の示数が大きかつた。出穂期が遅くなるにつれて東日本の示数が減少するのに対し西日本の示数が増大した。
(2) 8月5日から9月20日までの間の出穂期について最大示数の分布をみると, 我国で最も大きな示数を獲得できる地域は北海道石狩平野の一部, 裏東北々部, 西九州等の地域と考えられた。また示数の最も小さい地域は関東平野中央部等であると考えられた。
最大示数を示す出穂期は, 北海道, 東北地方北部では8月5日以前で, 南に向うにつれ遅れてゆき西九州, 四国南部では9月10日であつた。
(3) 示数構成要素からみると示数最大になる時期はいずれも登熟気温が21～22℃を示す出穂期であり, 示数の大きさはその時期の日照時数の多少によつていると考えられた。そして北海道, 東北では低温が示数の制約条件であり, 西九州では高温が, 関東では寡照が示数の増大を抑えていると考えられた。

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The influence of the performance of an evaporative fan-and-pad system on climatic conditions in a glasshouse was studied in this paper. Measurments of air temperature, air humidity and wind velocity in and out the glasshouse (east-west orientation) with the scale of 11.2m long and 5.2m wide were made respectively during the summer seasons of 1964 and 1965.
The evaporative pad was set on the north side wall of the glasshouse and four exhaust fans (0.4KW) with the diameter of 50cm were also set on the south side wall. The ventilation rate of this glasshouse was expected to be 180 times per hour. In the summer of 1964, no more than 40 per sent of the ventiration was found to be drawn through the evaporative pad because the house was not very air tight. In the summer of 1965, the house was repaird in order to prevent the draft. Results obtained in the experiments can be summarized as follows;
1. Air temperature was lowered considerably by passing through the evaporative pad as can be seen in Fig. 1. The cooling effect of the fan-and-pad system was much larger in 1965 than that in 1964, because the air ventilation in 1965 was almost made through the pad and fan system. In experiments of 1965, air flow in the house was relatively uniform just behind the pad, the wind speed somewhat decreased in the central section of the house and increased again before the each exhausting fan (see Fig. 2).
2. The pad temperature was found to be in accordance with the temperature of a wet bulb treasured out doors (see Fig. 3 and Table 1). However, the air temperature just behind the pad was slightly higher than the temperature of the wet bulb. No significant change of the cooling effect of incoming air with the water volume flowing down through the pad was observed in our experiments (see Fig. 4).

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1965年の夏 (26June～5Oct.)に「河川流域における水収支機構に関する研究」の一環として埼玉県鴻巣市にある農事試験場の隣接水田で行なつた長期連続気象観測の資料が間接法 (熱収支法・複合法・傾度法) を用いて蒸発散推定に使用された。すべての記録は1時間ごとに平均され, これらを用いて蒸発散の時間量が推定された。これに基づいて日量, 半旬量などが計算された。それらからえられた結果を要約するとつぎのようである。
1. 水稲の全生育期間における全純放射量 (ΣS) と全雨量 (Σr) を用いて計算した放射乾燥度 (=ΣS/Σlr) は0.89となり, 巨視的な生育期間気候は中湿よりやや湿潤状態にあることがわかつた。放射乾燥度から求めたE_T/rは0.72となり実測値0.73と非常によく一致した。
2. 全期間の蒸発散量は熱収支法では309mm, 複合法で347mm, 傾度法 (Bulk 法) では317mmになつた. これらはいずれも隣接水田内の露場での小型蒸発計の値 (379mm) より低かつた。水田に与えられた純放射量が蒸発散のみに使用されると仮定したときの最大可能蒸発量は378mmとなり, 小型蒸発計の値と一致した。
3. 蒸発計値に対する水田蒸発散量の比は全期間についてみると0.82となり, 現在まで水田内での水収支法でえられている比 (約1.2) に比較して小さい。このような差異の原因としては, 平均化期間の差異 (熱収支法などでは全生育期間が使用されているが, 水収支法では雨天以外の期間が用いられている), 測定地点周辺の環境の差異 (周辺反射光と空気の群落内への流入など) などが考えられる。
4. 水田の純放射量と蒸発散量との間には生育の段階に無関係につぎの比例関係が成立することがわかつた:
E_T=0.82S_*
これは他の研究者によつて潅漑 ryegrass 畑や水田でえられている関係とよく一致した。多湿な広い水田地帯では移流熱の影響はなく, 水田上の Bowen 比は常に正で, 約0.22となることがわかつた。
5. 複合法による蒸発散値 (E_C) と熱収支法による値 (E_T) との間にはつぎの関係があり
E_T=0.92E_C,
複合法は水田蒸発散量の推定に有効であることがわかつた。Bulk 法と熱収支法との比較から, 測点のちらばりは若干あるが, 両者は大体一致することがわかつた。
水田蒸発散量の間接推定法は比較的に妥当な結果を与えることがわかつたが, 現在まで報告されている蒸発計の値と蒸発散量との比については若干の差異のあることがわかつた。これは水田用水量決定上における重要な問題であるので, 広い水田内に大型秤量ライシメーターを設けて, 直接法と間接法による水田蒸発散量の比較測定が必要である。

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A basic equation for transpiration rate from a plant leaf may be written as follows
W_T=εDΔC_L, where W_T is transpiration rate, ε: physiological factor, D: transfer coefficient of water vapor from a wetted leaf-shaped plate surface to the bulk air, and ΔC_L: water vapor concentration departure of the leaf surface from the bulk air. The vapor transfer coefficient is given by the boundary layer theory and laboratory-experiments. But, there is not much information on the coefficients under the field condition in which the air flow is turbulent and solar radiation is strong.
This paper represents some information as to the evaporation of water from a watted plane surface under the field condition.
A circular plane has no effect of wind direction. Moreover, a wetted surface made of very smooth cotton cloth colored like a citrus leaf surface is not disturbed by wind like as free water surface. Then, the horizontal circular plane whose surface was always wetted, being supplied from a water reservoir under-placed was used in the field.
The evaporation rate from the upward-facing horizontal circular plane surface, 20cm in diameter, was measured simultaneously with the temperatures of the wetted surface and the bulk air, water vapor pressure of the air, wind velocity, solar radiation, etc.
Thirteen-day data obtained in summer clear days, 1959, were analyzed and the following results were obtained,
1) As long as the wind velocity is constant, the temperature departure of the wetted surface from the air increases approximately linearly with insolation and the lower wind velocity is, the larger the increasing rate.
On the other hand, solar radiation being constant, the temperature decreases with increasing wind velocity, and the decreasing rate is larger under lower wind velocity.
2) When wind velocity is constant, there is a linear relation between the evaporation rate and the vapor pressure departure of the evaporating surface from the bulk air. The proportional constant is larger under higher wind velocity than that under lower wind velocity.
3) As long as the vapor pressure difference is constant, the evaporation rate increases with increasing wind velocity, and the increasing rate is larger under lower wind velocity.
4) When the wind velocity is relatively large, the evaporation is mainly caused by forced convection. But, in the case of relatively larger vapor pressure departure in the daytime, the transport by free convection is considerably effective to the vapor transfer. Even though at around 4m/s in wind speed, the transport by free convection is about 10 percent of the transport by forced convection.
5) Under the field condition, transfer coefficient of water vapor by forced convection increases with four-fifths power of wind velocity. This numerical value of the power shows that the boundary layer over the surface is turbulent.
Then, in the range of normal air temperature and solar radiation, average water vapor transfer coefficients D of an upward-facing horizontal circular plane surface, 20cm in diameter, are given by the following equations,
(1) for upward free convection,
D=0.81×|ρ_A/ρ_S-1|^1/4+2.02+10^-2u^4/5(cm/sec),
(2) for downward free convection,
D=0.41×|ρ_A/ρ_S-1|^1/4+2.02×10^-2u^4/5 (cm/sec),
where ρ_A and ρ_S are the densities of the air outside the boundary layer and at the surface, respectively, and u is the velocity of the outside wind.

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Many papers are published about the aerodynamical saltatorial mechanism of soil and about the effectivity of several protection measures against winderosion. Recently they are interested in the physical and chemical properties and in the vertical distribution of saltant soil particles. For this purpose, several apparatus are applied to gather saltant soil particles (Fig. 1, No. 1-8). The small sized particles with the trifling inertia energy will either run out because of the accelerated airdrawing, or not enter at all, for the streamline is strongly disturbed already at the entrance of the apparatus (Fig. 1, No. 1-8).
In order to catch the small sized soil particles besides great soil particles, the authors have devised a new model (Fig. 2), at whose exit the speed of the airstream is diminished until 1/36 of the initial speed. Thereafter the floating particles need about 1.1 seconds to pass through the apparatus. In this 1.1 seconds a particle (specific gravity 2.0) with the radius of 14 micron falls 5.5cm (calculated by McCubbin's formula). Moreover the new type apparatus has no disturbance at its entrance (Fig. 1, No. 9 and 10). The entrance of the apparatus is built so low for the great soil particles, that they are affected directly to creep and fall into the gathercase.
The comparative examination of several apparatus on their gathering ability of saltant particles shows that the new type possesses substancially better gathering ability especially of the smaller particles (Table 2).
As the apparatus for practical use we have built the black painted apparatus made of iron plates with a vane. The apparatus is fastened up on the iron rod with a ball bearing and may be therewith turned (Fig. 1, No. 11 and 12). In order to research the vertical distribution of saltant particles small changes are undertaken on the size of the entrance and the exit; the entrance section 1cm×5cm and the exit section 7cm×29cm.

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