The principal subject on the land consolidation in the sloping paddy field area is the countermeasure to the distrupution of constructed ridge. The field investigation showed that the ridge distruption was caused by percolation water from the surface of slope. From the experimental result of the two-dimensional percolation flow analysis using Resistance-Network analogue, we have examined and discussed the effectiveness of various preventive measures for the ridge distruption. The obtained results were as follows:
1.Widening of ridge's width and laying of water block plate had little effect and were inefficient except an extreme case.
2.It was very effective to drain percolation water outward by the laying of underdrain or permeable layer on the lower part of ridge, because there was no percolation from the surface of slope.
3. The ridges constructed with scrupulous care showed an extreme decrease of the amount of percolation water with restrained permeability. Thus, this measures was highly effective.
Thus it was concluded that the most effective measures for preventing the ridge distruption is to make the simple drain on the lower part of ridge and to construct the ridge scrupulously.
Furthermore, using the 6-method, we have generalized the flow conditions of percolation water defined by the degree of finish of the construction of ridge, and showed that if the ratio of the coefficient of permeability between paddy fields and ridge are obtained, conditions can be indicated from Fig.6 in any situations.

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The two-dimensional orientation of soil particles is easily treated if it is measured and analyzed by the vector method for sand and by the optical method for Clay. The arrangements of particles obtained by these two methods are not able to compare each other within the resolving power of optical microscope, and then model arrangements are investigated by studying the intensity of light transmitted through them for comparision of both methods.
A simple apparatus for measuring the intensity of light was set up in a polarizing microscope, and from the measurement of intensities of light passing through optically anisotropic particles and given an experimental equation is given from the difference of transmissions through parallel and crossed nicols. The model arrangements for that indicates the variation between two directions of particles are expressed by the ratio of minimum and maximum intensities of the above equation, on the basis of an assumption that the long axis of a particle coincides with the direction of oscillation of either ordinary or extraordinary ray in it. It is, however, not able to make a comparision of the arrangements between single particles given by the above two expressions, because the random arrangement defined by the ratio of intensities is different from the trigonometric one. For this reason, the application of some spatial distribution function is necessary to consider in relation to both methods.

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Moisture changes due to heat (including such as condensation) have been neglected in past studies of soil moisture transport phenomena. The effect usually limited to laboratory study, and none have ever considered its significance in the field condition. In fact, soil moisture is not constant during the day and whenever there is temperature gradient occurs between the layers, moisture is transported due to the gradient. This paper was aimed to study the in situ effect of heat on moisture movement in vapour and liquid phase in the soil, by assuming that Philip's equation could be extended to such a case. A series of experiments has been conducted at selected areas of the Hamaoka Sand Dunes in Shizuoka Prefecture to collect all data required by the equation. Antecedently to the analysis, a stationary cross section' difining the layer having constant moisture content was set up, and the amount of moisture moved (including both gaseous and liquid phase) across this layer was calculated to obtain the mass flux, while the rate of condensation at the ground surface was estimated by the diffusion equation (1). From the results obtained it was found that the volumetric moisture content near the ground surface increased by 1% during the night (Fig. 2, Fig. 3). The types of moisture flux contributed to this increment arranged in thier order of magnitude, are:(1) Upward movement of liquid water due to moisture gradient, (q_θliq);(2) Upward movement of liquid water due to temperature gradient, (q_Tliq);(3) Upward movement of gaseous water due to temperature gradient, (q_Tvap);(4) Vapour condensation from the atomosphere to the ground surface, (Q);(5) Upward movement of gaseous water due to moisture gradient, (q_θvap), (Table 2).
Furthermore, it also clarified the fact that most of the condensation during the night was due to moisture transport rising from the lower layer. In computing the mass balance, the unknown quantity K₁-K₇, (hydraulic conductivity) was derived directly from the experiment. The value of the hydraulic conductivity was determined as K=3×10^-5cm/sec at 7% volumetric moisture content, which lies well within the range of its possible value.

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With a view of obtaining basic data necessary for making a future plan of irrigation and reclamation of farm-land in the polder field of Hachiro-gata, the actual condition of soil moisture fluctuation during the continuous dry season in the hayfield was investigated.
The following are the main results of this study:
(1) The relation between the soil moisture tension and the moisture content in the hayfield gives an almost coincident with the pF-moisture curve of drying process obtained in laboratory experiments.
(2) Because the surface soil is nearly at the limited height of the capillary action and the shell stratum is nearly at its limited height, the daily variation of moisture of the surface soil and subsoil shows different characteristics sharply.
(3) The hourly variation of soil moisture tension corresponds to that of the amount of insolation.
(4) The decreasing speed of groundwater level after continuous dry weather is nearly twice as fast as that before continuous dry weather.
(5) The supply of groundwater usually occurs from the surface soil when it rains, but the relation between the surface soil moisture evaporation and the groundwater is interrupted after the groundwater level falls down to the shell stratum.
(6) The field capacity has pF of 1.5-1.7.

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The purpose of this paper is to investigate the mechanism of water holding capacity of volcanic soil in South Kyusyu on the basis adsorption theory.
In the experiments, the specific surface of several kinds of volcanic soil were measured by the BET method (adsorbents: H₂O and N₂).
The fine porosity of the soil was analyzed by the Incley's method.
The results obtained are as follows:
1) The specific surface of soil increases in due order; sand, alluvial soil, SHIRASU, KUROBOKU and AKAHOYA.
Though there is no notable difference in the specific surface between alluvial soil and KUROBOKU, but the value of AKAHOYA is about ten times as large as that of alluvial soil.
2) The amount of micro pores increases in the order as mentioned above.
3) The water affinity of KUROBOKU is about seven times as much as that of AKAHOYA.
4) Though the water holding capacity of KUROBOKU and AKAHOYA showed high values, the mechanism essentially different in both of them.
The water holding capacity of AKAHOYA is indebted to the specific surface and micro porosity. On the other hand, that of KUROBOKU is strongly indebted to the water affinity.

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In the southern part of the Gifu Prefecture, especially around Kagamihara city, there distribute the black soil, a kind of the organic soils, that is called the Kuroboku soil of Kagamihara or the Kagamihara Kuroboku soil. The author and his coworker studied experimentally the physical properties of this soil.
The results are summarized as follows;
(1) This soil is rich in organic matter contents, has a high moisture holding capacity, and is acidic due to proceeded humification.
(2) The principal clay minerals are 14A° minerals and Kaolin minerals, in contrast with the typical volcanic ash soils containing allophane as the principal component.
3) Once disturbed the soil showed a great decrease in the unconfined strength and the permeability because of its high seneitivity.
(4) The samples subjected to the drying experiences change their dynamic properties; the chang is irreversible.
(5) It is found that the over consolidation can effectively lengthen the stress relaxation time; this feature is useful in practice.
(6) The Kagamihara Kuroboku is, in general, inadequate as aworking material; however, the soil stabilization by the use of the chemical agents, i. e. adding Ca (OH)₂ and auxiliary agent Ca (HPO₄)₂+2(CaSO₄·2H₂O), is very effective in improving its strength.

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The placing process of dam concrete is controlled by many limitations. Among these limitations, however, the magnitude of manpower engaged in the work of setting up and taking down of molds for placing concrete blocks is regarded as the severest one under a given equipment capacity, because there exists some limitation in manpower generally in the actual dam construction work.
In this paper, a new method is proposed for finding an optimal concrete placing schedule under the limited manpower for the concrete mold work. This method is based on the technique of PERT/ MANPOWER modified by considering feasible working conditions such as the division of day by work into several stages and the temporary shift of workers from surplus job to deficient job.

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