[in Japanese]

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In the sprinkler application the attachment of chemicals stricken against leaves is given by the disintegrated droplets. The present report deals with the experimental investigation on the size distribution characteristic of disintegrated droplets. The results obtained are summarized as follows:
(1) After the droplets strike against the leaves, there occur cornua in the initial period of development. In case the leaves are dry, the number of cornua is very few, and in case the leaves are wet, a thin-film like liquid is pushed around to extend in a crown form.
(2) When the leaves are wet, the amount of disintegrated droplets increases remarkably. By sprinkling water immediately before sprinkling chemicals with a sprinkler, the effect of disintegrated droplets is raised, and the amount of chemicals used may possibly be reduced.
(3) The smaller the relative collision angle between the leaves and the primary droplets, the larger the disintegrated droplets occur. As the leaf inclination of fruit trees such as orange is generally close to horizontal, the disintegrated spraying effect is enhanced whert the elevation angle of the nozzle of the sprinkler is large.
(4) No difference is observed in the number of disintegrated droplets whether the leaves are vibrated or not, from which it can be said that the influence of vibration of leaves is slight in the collision of droplets against the leaves.
(5) Concering the vibration of leaves, the minimum diameter of the disintegrated droplets is below 0.1mm, and the diameter Dp corresponding to the average value in volume is of the order of 0.6mm, so that, since the largest frequency value of the diameter of disintegrated droplets is of the order of 0.17 mm, that is, extremely small, it may be concluded that only a part of the disintegrated droplets contributes to the attachment of leaves at the upper portion of fruit tree.

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Since division works as well as water measurement faclities in an irrigation canal system are important in order to maintain and control irrigation water, there are many reports on water division and water measurement to make best use of irrigation water.
On the other hand, a variety of division works has been devised from ancient times, and some of them are fulfilling their function even today at various parts of the world. But it can be said that there are no division works which satisfy all conditions required.
Especially in case the main canal discharge fluctuates in a wide range, and floating trashes such as shrubs and weeds are blown or flown in water-course to cause sediment particles to flow down along the canal, the function of division works will be lowered and both maintenance and control of irrigation water will become difficult.
This paper discusses the characteristics and practical applicability of BACK STREAM TYPE fixed rate division works which will be established at a step of about 1 m in height in a main canal as shown in Fig. 5.
The structure of this type division work is exceedingly simpler than others.
Morecver, it keeps the designed fixed rate division with a high accuracy by providing a given incident angle of nappe against the sloped floor set under certain conditions, without influence of up or down stream.
And there are little functional disorder with floating trushes or sediment particles, because these particles are flushed away towards downstream along the nappe guide board.
Therefore, it is no doubt that this type division work is one of the most effectual facities for dividing irrigation water.

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When we try to find effective water maintenance, we feel keenly the necessity of actual studies about the time structure of water appliciation in the terminal fields. Therefore, we investigated about the characteristics and time structure of irrigation water, especially in nonpaddy fields. This paper is based on the experimental data on farm ponds in the Toyokawa Irrigation System. The principal conclusions are as follows.
a) There is concentration of water use both daily and seasonally.
b) Water consumption in the actual fields is less than its planning value in the irrigation season, but there was much rainfall in the year of the investigation.
c) Water appliciation on a farm pond generally shows several patterns.
d) After a modern irrigation system has been constructed, multi-water applications for agricultural use are becoming remarkably.

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The influence of creep and confining pressure on shearing properties of compacted soils at optimum moisture content is shown in this paper.
The shearing strength and Mohr-Coulomb's strength parameters c' and φ are scarcely changed with creep stress.
The initial part of a stress-strain curve of compression test is strongly affected by creep, so the initial tangent modulus of deformation E_it of samples subjected to creep is larger than twice or more that of samples not subjected to creep. But the secant modulus of deformation at failure stress E_sf is scarcely changed with creep. E_it is increased with confining pressure p but E_sf is not always increased with p.
The hyperbolic function of stress-strain relation given by Kondner is only applieable for sandy soil at high confining pressure and for cohesive soil.

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Compared with transported soil, residual soil succeeds strongly the properties of its mother rock. If the mother rock is the same, the soils formed therefrom may have common properties to some extent. The authors are intending to clarify the physical properties of various residual soils having different mother rocks. In the present paper, the physical properties, especially the shear strength and pF moisture property, of residual granitic soil are described.
The following results have been obtained:
1) The residual granitic soil is mostly a sandy soil, and its clay mineral is mainly composed of Kaolin mineral. The specific surface of it is relatively small, therefore, the compaction curve shows a steep peak.
2) The strength parameter tan φ' and C' of sandy “Masa” soils such as Omishima C soil, Hiratake soil and Samukawa soil are not varied perceptively according to the difference of the ratio of molding water content. In this case, it is considered that the interlocking between soil grains mainly governs the strength parameter tan φ' and C'.
3) The parameter tan φ' and C' of fine-grained soils such as Omishima A and B soils vary with the difference of molding water content to a large extent. In this case, it is considered that the strength parameter. tan φ' and C' are governed by the material combination between the soil and water rather than the interlocking between soil grains.

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