Following Inoue's (1957) suggestion the aerodynamic method of measuring the CO₂ assimilation and/or respiration of plants over wide fields has been applied to a wheat field during a whole day in May of 1957. This method, which was first applied preliminarily to a paddy field in September of 1956, makes use of the aerodynamic relation of turbulent transfer as
P=(U₂-U₁)(C₁-C₂)/{2.303/klogZ₂-d/Z₁-d}
where U₁, U₂ and C₁, C₂ are the wind velocity and the absolute concentration of CO₂ (for example, mg CO₂ perliter air), k the Kármán's constant (0.4), d the zeroplane displacement, and P is the turbulent flux of CO₂. The positive and negative values of P are respectively corresponding to the respiration and assimilation of plants over the field. The choice of the heights Z₁ and Z₂ must be adequate in order to the above equation be applied without the modifications due to the stability factors. The CO₂ flux from the soil surface has been neglected by examining the small gradient of CO₂ within the air layer amongst stalks. The assimilation rate in daytime and the respiration rate in night are reasonably shown in Table 1 aswell as the evapotranspiration and/or condensation rate χ of water vapor. A brief discussion of the apparent relationship between photosynthesis and evapotranspiration has been given.

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Recently the drill sowing is widely spreading in which wheat or barley is sowed along narrower furrows. It promises a good harvest and has an advantage that both seeding and reaping can be done utilizing animal power or machinery. We made an experiment on the effect of control erosion applying this method in a wind erosion area and could make the following points clear.
(1) In the case of drill sowing; the covering degree of the ground is much higher than in the case of ordinary sowing and consequently the surface of the ground is protected against wind erosion.
(2) The amount of the blown-off soil in the ordinary area was a half of that in the naked area, while in the drill sowing area it was one-third.
(3) In the naked area the erosion was 3 to 4 centimeters deep and in the ordinary area it was 0.5 to 1 centimeter deep, while in the drill sowing area no erosion was observed, and on the contrary soil was heaped up to the depth of 3 to 4 centimeters.
(4) As to the yield, it was in the proportion of 107 to 100 of that in the ordinary area.
The above-mentioned leads to conclusion that the drill sowing has a remarkable effectiveness against wind erosion and so is to be applied in wind erosion regions.

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An observation was carried out during July 27-31, 1957, in a small V-shaped valley dissecting Sugadaira high land, Nagano Prefecture. [I] When the prevailing upper winds crossed over the valley, the following results were obtained. (1) Ratio of the wind speed at the valley stations to that at the station situated on the horizontal high land surface is smaller at night than in the daytime. It is the smallest generally in the valley bottom and becomes larger to the upper edge of the valley side slope. (2) Deviation of the wind direction from the prevailing winds reached almost 90° at the lower part of the valley slope and had diverse component in the valley bottom. From these circumstances the eddies formed in the valley seemed to have some twisted character in the valley bottom. (3) The ratio of the wind speed at the valley stations dependen upon the prevailing wind speed, but an inverse relation in the daytime and a positive relation at night was found. This is originated by the development of relatively strong valley winds and the weak mountain winds in this region. (4) The eddies in the valley were produced even under the low speed (1-2m/s at 1 meter height) of the prevailing wind and irrespectively of time of day or night. [II] When the prevailing wind direction coincides with the running direction of the valley, there appear almost same wind speedsin the valley bottom as that on the open horizontal land. In some cases, however, the former was stronger than the later. Especially, the station located in the valley bottom becomming narrow had an anomalously wide fluctuation of the wind direction and a relatively strong wind speed.

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The profiles of temperature, humidity, and wind velocity have been determined by conventional methods in the lowest 6m of the atmosphere above a bare surface, with simultaneous of observations of heat absorbed in the soil and of the short-wave and long-wave radiative flux of heat. Thirty-six sets of observations were made.
The turbulent flxues of heat and water vapoure are also determined by an aerodynamic method which assumes equality of the eddy viscosity and the appropriate diffusion coefficient. Then the following equation of the heat balance on the ground surface is examined.
R-F-LE=C,
where R is the net radiation, F is the turbulent heat flux on the ground surface, LE is the latent heat of evaporation, and G is the heat absorbed in the soil.

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We have analysed the influence of the straw matting in the western part of Tokyo in the course of mulberry growth during the summer.
We have made experiments for lots, that is, storw matting, and no matting, in order to test the significant difference amoung them. The design of the plots and the cross-section of each plot were shown in Fig 1. The soil temperatures were observed at 9 every morning, at the soil surface, 10cm and 20cm below the surface. The soil moisture content were observed during the period between the 29 July to 7 August every 4 days at 10, at the soil surface, 20cm and 40cm below the surface.
The analysis was carried through by the methods of analysis of variance. Although the difference of the soil temerature can be seen in Fig 2, there is no significant amount of variation among the mulberry leaf yields by the use of lots,

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Since the measurements of air temperatures could not be obtained with good accuracy compared with measurements of wind velocities, sometimes we have felt difficulty in obtaining the relationship between mean wind velocity profile and temperature profile.
The cause of error occurred in temperature measurement depends on both the structure of apparatus and the method of observation, but only the latter is discussed here.
The mean wind velocity is easily obtaind from numbers of electric contacts of cup anemometer during the time, while the thermometer is read point to point. When the number of reading is one or two, it can not represent sufficiently the mean temperature for the sinusoidal fluctuation of temperature. It is necessary for the measurement of mean air temperature that the number of readings must be as many as possible during the averaging time and, therefore, the thermometer must have a rapid response, a quick indication and a high sensibility.
Copper-Constantan thermojunctions, a potentiometer and a galvanometer are usually adopted for temperature measurement in the micro-meteorological observations. In our experience, at least about 12 seconds were needed for one point reading by these apparatus. Therefore, when measuring points are 12 and observing time is 5 minutes, the readings are only twice per one point, which are too few to obtain the mean temperature.
The use of an electronic D. C. volt meter instead of a potentiometer and a galvanometer is very appropriate for rapid readings. When the range selector is set at ±250 micro volt in full scale, the minimum scale corresponds to about 0.125°C and one reading takes only 2-3 seconds. By this volt meter we could obtained a smooth profile from 7 readings in 10 minutes (Fig. 3).

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The auther classified in the previous paper the paddy fields in the Shichigashuku Village, Miyagi Prefecture from the standpoint of the temperature of irrigation water into the following four groups:
paddy area irrigated with water of low temperature (Max. water temp. below 20°C on Aug. 18)
do. of semi-low temperature (Max. 20-23°C on Aug. 18)
do. of medium temperature (Max. 23-25°C on Aug. 18)
do. of high temperature (Max. over 25°C on Aug. 18)
In each area, the representative paddy fields irrigated continuously with water or respective temperature were selected and the growth and yield of rice-plant therein were observed in relation to the water temperature. The results obtained were described and discussed in this paper.
(1) In each paddy field of all the area, the growth and yield of rice increased as the distance from the inlet of water became larger, just same as the temperature of water rose. But the ratio of the increase became less, so that the correlation curve between the increase of growth or yield and the distance from the inlet was parabolic, not linear.
(2) On the growth and yield of rice, the area of high water temperature predominated particularly over the other three. From the point of temperature, water of below 20°C gave serious cold injury to the plant and made almost all of spikelets sterile. The plant was also affected considerably by the water of 20 to 25°C, and especially the temperature of 20 to 22°C was distinguished with the remarkable falling down of the grouth and yield. Incidentally, it was conseivable that that this extent of water temperature would be critical to the growth of rice-plant. On the other hand, water of over 26°C influenced very little and that of over 28°C wo uldnt be troubled about the injurious effect to the plant under somewhat bad climatic conditions.
(3) The fertility of heads was also affected by the temperature of water irrigated. Dividing all the kernels into complete grains (wholly ripened) and incomplete ones (the others), the number or percentage of the former was increased in proportion to the distance from the inlet with just same patterns as mentioned in (1), and the tendency was particularly distinct in the area of low water temperature.
And besides, the ripening appearences in corresponding parts, for instance, water inlet of fields in each area were related with the water temperature; say, excellent in the the high temperature area and in turn.
On the contrary, the incomplete grains did not show so distinct tendency as the complete ones.
(4) Water temperature influenced differently on each tillering of the plant. By a certain degree of low temperature the main culm was injured the least; the higher the order of the tillering, the more the cold injury, general.
At the part of fields where water temperature was about 25°C, heads of both main culm and 1st-ordered tillers had almost same fertillity. Where it was about 24°C, heads of main culm had almost all of complete grains and a little of incomplete ones, while those of 1st-ordered tillers had about half of complete and incomplete grains. Below 23°C, the majority of grains remained to ripen incompletely.
(5) The above-mentioned results of field observations on the relation between the water temperature and the growth or yield of riceplant seemed to concur with many results of laborateory experiment already reported.

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[in Japanese]

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