To estimate the soil moisture from climatic data, the author decided the field capacity of the soil. When the soil saturated to the field capacity, 490mm of water is contained in the soil layer from earth's surface to 100cm depth. (see Table 1).
The author evalute the rate of evaporation from earth's surface as that from water surface. When the earth's surface is covered with the dry soil, the rate of evaporation from earth's surface is not exceed 1mm per a day.
The procedure to estimate the soil moisture from climatic data is shown in Table 2. Estimated and observed data of the soil moisture are shown in Fig. 1.

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In order to describe reasonably the turbulent characteristics of wind velocity fluctuations near the surface of cultivated field, the empirical turbulent energy spectra are introduced as follows:
F_u(N/N_0u)=2/3N/N_0u/{1+(N/N_0u)²}^4/3 and F_w(N/N_0w)=2/3N/N_0w/{1+(N/N_0w)²}^4/3, where N denotes the passage-frequency of turbulon, and N_0u and N_0w do those of the largest (or coupling) turbulon for u-and w-component respectively. These spectra represent the -5/3 power relation at large N and the 1 power at small N.
By means of the partial integration and the Fourier transform of the above spectra, the influence of the change in averaging procedure on the observed turbulent energy and the functional form of the Eulerian correlation coefficient of velocity fluctuations in particular for the range of not necessarily small process time t, are obtained. These theoretical results are compared to those obtained in practical observations reported in the last paper (part 3) of the same authors, and the particular characteristics of the latter are shown to be explained as follows:
(1) When the averaging-time T* is sufficiently larger than the passage-time of the largest turbulon, the change in T* does not cause any remarkable increase in ‹u′²›, whereas when T* is sufficiently smaller than the passage-time of the largest turbulon, ‹u′²› increases with T*^2/3.
(2) When the averaging-time is too much large compared to the passage-time of the largest turbulon, sometimes the contributions of the larger-scale turbulons caused topographically, geographically, thermally and so on, to the observed turbulent energy ‹u′²› predominate. These contributions seem to cause the vertical gustiness distribution independent of height, and to give rise to the result of ‹u′²›^1/2=const. U(z)=const. log (z-d), where z, d and U(z) mean the observation height, the zero-plane displacement and the mean wind velocity at the height z, respectively. However, according to the conditions whether the former be sufficiently smaller than the latter or be of the just same order, the vertical gustiness distribution increases with or independent of the height. Therefore, any simple empirical laws of gustiness distribution seem difficult to be universal.
(3) In order to obtain the Eulerian correlation coefficient corresponding to the well-known form of R(t)=1-const. t^2/3, the process-time t is much smaller than the passage-time of the largest turbulon. However, when the former is much larger than the latter, the functional form of R(t) is rather approximated fairly well by 1-const. t^1/3, where R(t)≤0.4.
(4) The practically observed results seem to suggest that the passage-time of the largest turbulon is almost given by 10(z-d)/U(z). The characteristic time T_z≡(z-d)/U(z) is tentatively called the equivalent passage-time of wind at the height z.
Furthermore, making use of these results, the necessary response time *T of the anemometer and the necessary length T* of averaging time for the measurement of the intermediate turbulon range (or the inertial subrange) are suggested to be given by *T=(z-d)/U(z) and T*=100(z-d)/U(z) respectively.

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It is said that the area protected by the windbreak is the regular triangle on the leeward of the wooded belt, which is the base of the triangle.
It is very important to know the change of wind direction and also the protective area of the shelter-fences, so as to construct proper fence.
The following may be mentioned as the causes of the chage of wind direction.
1. Valley
No matter in what direction the wind may be blowing, the wind has a strong tendency to blow along the valley.
3. Interstice of wood land or wooded belt.
The wind in the wood land is inclined to change its course to right angles to the wooded-belt, as it advances. At the interstice, it changes in the direction of the opening.
3. Roughness of the ground.
It is due to the state of the surface of the ground, such as grassy plain, cultivated land, bare land, and so on, that the wind suffers a change of direction. The greater the obstacles to the windward, the more the wind chages its direction of blowing. In consideration of the above fact.
I have conducted an experiment shown as under:-
Result of the experiment.
1. When the wind blows at right angles to the fence:
In this case, on the leeward at both ends of the fence, not as in the central part, the wind is noticed to blend with the wind outside the covering and the ratio of the wind velocity is greater. Though the fence is 15 times as high, the velocity decreases by 30%.
The the protective area of the fence stretches itself into a form of a rectangle.
2. When the wind blows at oblique angles to the fence:
In this case, the protective area is made much narrower. If deviation from the main wind direction to the right or left occurs, the protective area takes a shape of a triangle. The relation between the length of the wooded belt and the protective area is expressed by the formula: y∞L² (y indicates the protective area; L the length of the wooded belt). Therefore, it is more advisable to lengthen the wooded belt as much as possible.

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It is a common occurence that typhoons strike frequently the southwest zone of Japan (Kyusyu, Shikoku) from August to September everyyear, since this period is the same as earing stage of the paddy rice in that zone, injuries of rice by typhoon are heavy.
The wind injury of the paddy ricce is not only largely influenced by the wind velocity, its blowing duration, growing condition of rice, but also influenced by the temperature and the humidity of the wind.
In order to research the difference of injury between wind-only treatment (10m/s, 3hr.) and wind and rain treatment (rain by shower in addition to wind), we carried out the experiment in the wind-tunnel at earing stage of the paddy rice.
The results are following.
1) The injury of wind only treatment was heavier than that of wind and rain treatment, that is, the former showed larger increase in sterile spikelets, spikelets of fertility injuries than the latter.
2) The transpiration rate of rice by wind treatment showed remakable increase compared to that by non treatment, but that by wind and rain treatment was lower.

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In order to find out the relationship of water temperature with the nutrition and metabolism of the rice plant, some water culture experiments were carried out: in the first and second experiments amounts of nutrients were measured with a definite interval and in the third experiment nitrogen and carbohydrate constituents in the top and the silicification of epidermal cells of leaf blade were determined under different water temperature. Results of experiments are as follows:
(1) Regardless of the variety higher (37°C) or lower (20°C) water temperature than optimum (30°C) reduced the absorption of nutrients, especially that of potassium. The low temperature reduced the absorption of water remarkably, resulting in the decrease in the moisture content of the top.
(2) Decrease in dry weight of the top and reduction in the absorption of nutrients and water due to low water temperature were less remarkable with Rikuu-132, a variety resistant to cool-weather, than with kamenoo, one susceptible to cool-weather.
(3) The water temperature higher or lower than optimum increasd the percentage content of NH₃-N, amide-N and soluble-N and decreased that of protein-N, resulting in a marked increase in soluble-N/protein-N ratio.
(4) Regardless of the water temperature the percentage content of soluble-N and soluble-N/protein-N ratio were lower with Rikuu-132 than with kamenoo.
(5) The percentage content of reducing and non-reducing sugars in the top was decreased by high and low water tempeatures whereas that of starch was increased by decreasing water temperature.
(6) The water temperature higher and lower than optimum conspicuously reduced the silicification of epidermal cells of leaf blade.

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Authors measured the absorption of water by the paddy rice, water content and dry matter of the paddy rice and the evaporation from the irrigated paddy field, in each growing period, 1954. These results are shown in Fig. 1-2 and Table 1-8.
Air temperatures in June and July indicated the minimum records, and so the growing of the paddy rites were very slow. Therefore the absorption were few at first. The maximum absorption appeared from 25 days before the heading, the glume-primordial differentiation stage, to the heading similarly in 1953.
The water requirements of the rice plants were from 230 to 305. The evaporation from the paddy field showed the similar values in the observation field till early in July and, had been decreasing with the growing of rice plants. The net duty of water in the paddy field (absorption+evaporation) showed the maximum in the latter half of August, 350-510lit/are/day.

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In order to add an information for clarification of mechanism of yield lowering induced by the abnormal codition of air temperature during winter season as seen in 1954, we observed the growing process of wheat plant (variety; Norin No 61, spring type) from January to April in 1954 and compared with it in 1952. Summary of results can be stated as follows:
1. Air temperature from January to March in 1954 was somewhat higher than in 1952 and futhermore the irregular variation (rising at middle Jan. and Feb., and dropping at early Feb. and middle March) was seen. However, no essential difference upon the amount of rain fall and the hour of sunshine were found between 1952 and 1954.
2. Rapid elongation of plant height and culm shooting in 1954 were begun at earlier date of growth than in 1952. Stem number in 1954 increased rapidly from early January and gained the nearly maximum number at middle February, though it in 1952 increased slowly at first, became rapid gradually in increasing velocity with progressing of growth and a time of the nearly maximum number corresponded fo about early March. On the other hand, the beginning time of its decreasing was nearly simultaneous in both years. Consequently, the time duration keeping the nearly maximum number in 1954 was about 20 days longer in 1952.
3. A stage of bract primordia differentiation (stage V stated by WADA) was about 30 days earlier in 1954 than in 1952, while a stage of flower organ differentiation (stage X) was about 15 days earlier alone: accordingly, the time duration from stage V to X was about 15 days longer in 1954 than 1952. From this fact it is considered that the probability of lowering of yield was included on higher percentage in wheat plant of 1954, because the early period of spike formation is apt to be affected by various environmental factors as seen in hitherto several reports.
4. Dry matter percent in plant body during January to February in 1954 varied ranging from 10 to 150, though it in 1952 continued in about 15% level, that is, it in 1954 was relatively lower and had striking variation. Next, when seen the increasing curve of total nitrogen and decreasing ones of carbon compounds (total carbohydrate, reducing sugar and invert sugar) of plant body, the clear difference could be found between both years. Thus, it is supposed from these results that the growing habi of wheat plant in 1954 was also differed in physiological state with it in 1952.

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