Agricultural land tractors and auto-tricycles popularize in a farm village. The width of agricultural road is enlarging by the land readjustment. It perplex farmers that the arable lands diminish and the costs of road construction become expensive. The author investigated the real conditions of road. Two meters width is inconvenient, for the vehicles to cross. But the agricultural road is not the high way and the high-speed cars need not cross in it. The width has a limit. Asthe agricultural hand tractors and oxcarts can cross, 3.6-4 meters width is proper in flat ground. Due to some amount of the traffics, the road before the farmershouse needs enlarge.
In the farm-village which carried, out the land readjustment before the War, farmers are perplexed by the narrow road. They feel uneasy about the land readjustment at present. But in the collective farm, farmers use agricultural implements on the road of two meters width.
The author investigated the arrangement of agricultural roads too, some of which are unnecessary.The author considered the standard of their arrangement.

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As the standard partition of the land readjustment, the farmers have been dividing the agricultural land into 54. 5 m in length and 18. 2 rn in width for a long time.
The agricultural implements popularize of late and the roads expand, so the acreage of agricultural land is on the decrease. Many farmers suffer it. The large partition effects to solve it. But the drainage-condition of agricultural land obstructs the large partition.
We must improve the drainage to make the large partition.
In Japan, the farmers cultivate a rice field in hilly country. On the land readjustment, the farmers make a levee into a straigh line, the cost of construction is expensive. We must make the partition of agricultural land along a contour line.

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An accumulated intake rate formula in field is generally fixed by multiplying a furrow intake rate by b/B, in which the residual water can not be exactly estimated. So, a method by measuring the residual water was taken in this paper, in which an accumulated intake rate formula was found to be effected by discharge and slope of furrow.
As a ponded furrow irrigation uses the small amount of water rationally, we must notice how much intake water can be supplied by the residual water. For estimating the final distribution of water, it may be practical to consider the residual water independently.

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In this report the authors indicate, using Wagner's pots, that physical and chemical properties of upland soil are closely related to irrigation practices.
Changes in physical properties:
In non-irrigation and irrigation plots, the permeability of soil gradually decreased. This is due to surface crust formed by the impact of raindrops. The crust is easily broken by scratching and then the permeability increases again. By optical observation it was found that the structure of such a crust was different between the two plots. The crust in the irrigation plot was thicker and more stable than that in the non-irrigation plot. The bulk density of the top soil in the non-irrigation plot increased by the action of raindrops. No such crusts were found in the water-ponding plot and the permeability was stable all the time.
Changes in chemical properties:
The value of pH in the non-irrigation plot was the lowest. The top soil in the irrigation plot and the water-ponding plot were relatively rich in water-soluble calcium and exchangeable calcium. It was found that the quantity of exchangeable potassium of the top soil in irrigation plot was the lowest.

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The experiments upon which this report is based represent an attempt to learn the changing of the permeabilitykwith the progress of time in twelve cases obtained by combining the conditions of air contained in soil pore space (including large pores made by little animals) and those of air dissolved in percolating water. The results are as follows:
In case of unsaturated percolation with air-closed system such as the percolation of soil layers containing bubbles in pores, the permeabilitykincreases with time in accordance with the degree of unsaturation with air of percolating water (the degree is higher for less air dissolved). This is because the air in pores dissolves in percolating water and extends the cross sectional area through which water passes.
The percolation in paddy field is almost an unsaturated percolation with air-closed system; so that these results suggest that the permeability changes all the time by the amount of air dissolved in percolating water which depends on meteorological and other factors.
This is a remarkable character of percolation in paddy field and is different from that of ground water percolation.

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This paper is a continuation of the preceeding one which reported the water infiltration process uniform columns of dry sands and glass particles packed in laboratory. In this study the same packed glass particles were used, but this time, layered conditions were investigated. And always the smaller particles overlaid the greater particles.
In the infiltration process in the upper layer, the same results as before were obtained. But in the lower layer the two different flow types were found. One was usual type and the other was, so to speak, partial type. In this type the water did not flow in all section of permeameter, but flowed in partial section having the boundary of air-water surface on every side (Fig. 6). So its average water content was lower than that of the upper layer. Then the type of the variation of the water. entry rate were quite different from that in usual flow.(Fig.8, B).
We tried to make clear the properties of this flow, and have been successful in the illustration of the reason why this partial flow occured, and a necessary condition for it (q₃<K₂, eq, 18.).
Further more such a trial was done not only in the infiltration process but also in the ensuing percolation stages. Then these theoretical considerations and the derived equations nearly agreed with experimental results (Table3).

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Water percolation can be controlled by giving Bentonite in the excessive percolative paddy field. One of the factors for this is assumed as follows; when the suspension of Bentonite percolates through the effective pores of the soil, they are reduced or closed by it.
We testified this assumption by using a porous cup of earthenware which porous structure remains the same through the percolation and ponding the suspension of Bentonite to percolate in its wall.
It was definitely shown by the experiments that Bentonite is very dispersive, and that the more structurally viscous the suspension is, the more it controls the permeability of the earthenware.
On the other hand, the limitation of permeability of the suspension to percolate into the porous earthenware was k=3-4×10^-4 in the case of the suspension dispersed in pure water, and in the chloride solution k=2×10^-4.
Next, in order to get the limitation of permeability of Bentonite suspension to percolate or run through the actual soil, we prepared the several soils with different permeability and added Bentonite into them.
From the above experiments it was shown that when the coefficient of permeability before adding Bentonite is at the degree of k=1×10^-2, the added Bentonite percolates or runs through the soil, and at the degree of k=3. 5×10^-3 no percolation flow of the Bentonite suspension from the soil can be seen, this degree being equal to decrease of water depth 3024mm/day.
So we conclude that the percolation control by adding Bentonite is effective only in the very coarse soil, but its effect is very unstable, and then it is unnecessary to take account of such a factor in ordinary percolative rice paddy field.

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1. The tendency of change of NH₄-N concentration during irrigation season is about the same (Fig. 1) with that in 1958, from which we can see that (a) a big percolation (35mm, 45mm/day) is observed in paddy field where productivity is remarkably decreasing, (b) NH₄-N concentration absorbed by rice plant is high in paddy field with low percolation (5mm, 15mm/day) (Fig.2).
2. In yearly change, water temperature in paddy field with no percolation is higher than others, soil temperature is lower. Daily fluctuations of water-and soil temperature are seen in an interesting relation.
3. The length of plants is about the same with each other.
4. Tillering is showed no big difference between the plots (Fig. 6).
5. About the relation, between yield and percolation water quantity, the plot with percolation 5-15 mm showed the largest yield, and no percolation plot, 25 mm plot, 35 mm plot, more than 45mm plot gave the smaller yield in this order.
Thus the moderate quantity of irrigation water is calculated by the moderate one of percolation.

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Experiments were conducted to clarify the mechanism of consumption of water storagein upland containing the more water in lower layers, and the evapo-transpiration which is the essential part of the consumption. A floating lysimeter in Fig. 1, was used. The results are:
1) The water for the maintenance of rapid crop growth lies in the range between moisture content 24 to 48 hours after irrigation and that around pF 3.2. If moisture content reaches pF 3.2 in the layer including more than 50% of root hair, the rapid crop growth will be hindered.
2) Evapo-transpiration changes mostly under the influence of meteorological factors within the moisture range mentioned above. The above results show that the value of moisture content to be considered for the planning of upland irrigation in Japan corresponds to the range of relatively low tention.
3) If shallow root crops are raised in soil layers containing the more moisture in lower layers, there exist tow different zones: the consumptive zone mostly consisting of root zone and the supplementary one several tens of centimeters under the, root zone. Moisture moves upward from the supplementary zone to the consumptive one about in proportion to evapo-transpiration. Such a supplementary water amounted about 50% of total evapo-transpiration in the experiment.
4) In the theory of soil moisture extraction pattern will not applicable the standard of the U. S. A., but also total readily available moisture estimated from the pattern will not show the true value if the measurement depth is not appropriate.
5) Based on the results, several methods were presented Shere to determine the total available moisture in the planning of upland irrigation in Japan.

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The author observed the relation between ice-columns and soil moisture of an upper layer inKanto-loam field (wheat field), Saitama Pref.
As it was difficult to clear up a small change of soil moisture during ice-columns growth, some methods of small sample theory and of the trial-error were adapted in treating the observed data.
The results are:
1) The depth of the soil layer where soil moisture moves is about 30cm.
2) Water contents of ice-columns changes linearly with soil moisture in an upper layer.
3) Under the weather conditions in which out-door temp. is lower than 0°C with no wind, etc, most ice-columns are seen in field capacity, and no ice-columns in about 28%(volume) of soil moitsure.
4) During ice-columns season, the relation between evaporation from soil surface and soil moisture in an upper layer is almost linear in wheat field.

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We have always noticed that the change of soil moisture makes it complicate to perform field experiements of irrigation.
Several years ago, I pointed out the importance of expressing soil moisture in volume % in order to take off this complication, which is recognized by clearing up the relation between the fieldcapacity of Kantti-loam and its porosity.

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Three phases of soil have been studied from edaphological point of view. For plant growth it is really profitable that gas phase per-centage is large until sub-soil, but this phenomenon is not here discussed sufficiently. The relation between three phases of soil and the other physical properties of soil should be shown in order to improve soil tilth. The author indicated that solid phase per-centage (S) is highly dependent upon its parent material and has almost similar value in the same parent material. As parent material of soil spreads over to a large extent, the influence of soil upon the cycle of water should be studied in the light of three phases of soil. Results are:
(1) To get the volume of solid phase S, liquid phase L, soil moisture ratio M₀ and gas phase A (=100-V) from the. measured ones of total weight of 100 cc fresh. soil. W, total volume of 100cc fresh soil V through a air-pycnometer, a compound nomograph was made for practical convenience (Fig. 2).
(2) Solid phase per-centage depends on parent material as the following series (Fig. 3). Alluvial>Tertiary1>Tertiary2>Volcanic mud flow≥Andesite>Tertiary3>Volcanic detritus=Volcanicash.
(3) The correlation between S and S_υ (=settling volume) is significant and that between M_eq (=moisture equivalent) and S_υ is more higher. S∝1/S_v, Mcq∝S_υ, (Fig. 4).
Relation between A and S is A=a/(S-b).
(4) On Japanese inner belt of Green-tuff Orogeny, the zones with many reservoirs have a topographical and geological feature relating to three phases (Fig.6).

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Study of deformation and flow of soil is one of the important problems in agriculture, and the behaviour of soils is closely connected to soil micro structure. In this paper the flow phenomena of soil paste were investigated, thereby some quantities in the flow phenomena are necessary to be clarified in exectly rheological sence in order to relate the rheological behaviour to soil micro structure.
Flow of soil paste was measured by co-axial cylinder viscometer. Bentonite used in this experiment was electrically dialysed to get a well defined sample. The cation. was 60 meq/100g, therfore the sample was not wholly dialysed. Results of flow were showed by the terms of “consistency variableP, V” according to M. Reiner (eqs. 1-4).
Results are summarised as follows:
(1) The relation between viscosity and temperature was considered after the idea of E. N. da C. Andrade (eq. 5). The change in viscosity of soil paste under critical concentration was negligible in ordinary roomtemperature.
(2) The relation between relative viscosity (η_r) and concentration of suspension (φ) was examined along with J. V. Robinson, Y. Mori & T. Ototake (eq. 6).φ is critical concentration above which soil suspension does not give Newtonian flow by shear.dis effective mean diameter of paticles, S_ris constant. Considering φas the effective concentration due to swelling, (eq. 6) is effective in soil paste. In Fig. 6 if 1/η_r=0, φ0 can be determined graphically. This value is almost equal to that of sedimentation volume.
(3) Above the concentration of sedimentation volume, the type of flow was of shear rate thixotropy (Fig. 7). On the other hand, under this concentration no remarkable thixotropy was expected. This type of flow still leaves much to be investigated.
(4) From the (Figs. 6, 7), we propose that the state of sedimentation is a critical point of flow, uuder which the soil paste behaves like Newtonian liquid, and above which Bingham body is seen.
herfore the authors defined the concentration of sedimetation as “critical concentration.”

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This paper presents outlines of the rainfall and runoff experiments and some general considerations of the observed data. The plots were located on the slopes in Kamigamo Experimenal Station of Kyoto University Forest situated in the low montainous area in the suburbs of Kyoto 130-230m above the sea level and were 3m wide, 18m long and had a slope of 24°. They were composed of 4 different kinds of surface covering: bare soil surface (Plot 1), dense turf covering (Plot 2), bamboo grass covering (Plot 3) and forest covering (Plot 4) with a medium stand of miscellaneous trees and a good humus layer 2-5cm deep. The data of rainfall, runoff, soil moisture variation, water movement in soil, etc. were obtained by self-recording instruments since 1955.
Through comparison of the data for Plots 1, 2 and 4, some remarkable characteristics of the runoff phenomena are confirmed.
First, the seasonal variation of surface runoff from Plot 1 is the most conspicuous of the three, and for several months in, the beginning of every year mass runoff from Plot 1 decreases below that from Plot 2. This characteristic is caused by the freezing of water in soil surface layer that granulates and enlarges soil pores and makes them more permeable again.
Secondly, the intensity-relation between rainfall and runoff keeps up almost unchanged after runoff occuring both from Plot 1 and from Plot 2. Corresponding to their soil texture (clayey soil), surface runoff takes place from both plots when the intensity of rainfall exceeds 2-3mm/h, which is a very low value, and also the intensity of infiltration increases together with that of rainfall.
Thirdly, the intensity of runoff from Plot 4 is lower than that from Plot 2 during the early period of runoff, and then after mass rainfall exceeding over 100mm it increases, abruptly and surpasses that from Plot 2. This characteristic is caused by the abrupt change of the intensity-relation between rainfall and runoff at the limit of mass rainfall.

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This paper deals with the hydraulics of the rapid acceleration divider and gauger. lt is different fron the convensional theory in that the theoretical flow by Belanger's theorem is corrected with an experimental coefficient, and that the condition of free flow is shown on experimental foundation (see Fig. 2).
The overflow depth h₃ is from Bélanger's law,
h₂=3√Q²/b²g...(a)
whereQ, bandgare flow per unit time weir width and gravity acceleration respectively.
As for the free flow on the weir,
Q=mb (E-h_z) √2g (E-h_z)...(b)
wheremis the coefficient of overflow.
From (a) and (b)
h₃=3√Q²/c²b²g, C=3√3/2m...(c)
Then the height of the weirh_zbecomes
h_z=E₃-(c²/2+1) h₃...(d)
E₃is the specific energy on the weir.
The next problem is the condition of free flow, it is
k=h_u/E₃-h_z≤0.6...(e)
The loss head of hydraulic jump ΔEis given by
ΔE= (1-k) (E₃-h_z)-αv₀²/2g...(f)
α≅1.1
Henceh_dbecomes
h_d=E₃-(E₂+ΔE₂+ΔE)...(g)
Based on these equations, designing procedures are shown for the case in which whether the weir width or loss head is given, and for the case in which both the weir width and loss head are given.

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The study was made in order to find out the mechanism of the blocking of the river mouth and to get materials for its improvement.
The size of shores and foreshore slopes and the diameter of drift were measured on the main drift shore of Tosa bay from Muroto to Ashizuri in Kochi prefecture. I studied geophysically the distribution of shores, its characteristics and drift transport, etc.
There is no remarkable differences geologically between the eastern and the western coasts. But the former has a larger slope a greater number of rivers, so that there is a greater quantity of drift.
Because the waves which act on th eastern coast are flatter and have more energy than those on the western coast, there is found more drift transport. Consequently, the on-shore drift are more often shown than the off-shore drift, moreover the foreshore slope and the diameter of the drift are large, which make the drift shore develop.
From such an analysis, river mouths in drift shores are classified into the deflective, straight and protective types, for each of which it became possible to decide the fundamental method of improving the river mouth.

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