This report shows arranged results of the mechanical-stumping tests of the new pine root stocks grown on the soil of volcanic ashes in Kamikita region, Aomori Prefecture, using several kinds of Rakedozer such as BF, D 7, BB IV, D 6, NTK 4 and D 4 types.
The results are summarized as follows
(1) The time required for stumping (t) corresponding with the diameter of root stock (d) somewhat scatters, because of great variety and complication of factors which influence on mechanical stumping. Therefore, the relation of (d) with (t) should be expressed with an extent. Table 8 is considered to be useful practically.
(2) The raking number (N) corresponding with (d) scatters in the extent less than (t) corresponding with (d). Therefore, there is room for studying mechanical stumping from this point of view. Table 9 is trial calculation (N)-(d) values.
(3) (t/ N) corresponding with (d) is the cycle time of mechanical stumping. Because t= N×t/N, Table 9 is considered to be useful practically, together with Table 8.
(4) Each raking method of various kinds of Rakedozer differs with one another. Test results show the characteristic of each type Rakedozer. It is explained in Table 10.
(5) Root types are essential factor for mechanical stumping. They are shown in Table 11.
(6) It is considered that the test results shown in this paper are one example of mechanical stumping of pine root stocks.

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This report shows arranged results of the mechanical stumping tests of the new cedar root stocks grown on the soil of volcanic ashes in Kamikita region, Aomori Prefecture, using several kinds of Rakedozer such as BF, D 7, BB IV, D 6, NTK 4 and D 4 types.
The result; are summarized as follows;
(1) The time required for stumping (t) corresponding with the diameter of root stock (d) somewhat scatters, because of great variety and complication of factors which influence on mechanical stumping. Therefore, the relation of (d) with (t) should be expressed with an extent. It is shown in Table 2.
(2) The raking number (N) corresponding with (d) scatters in the extent less than (t) corresponding with (d). Therefore, there is room for studying mechanical stumping from this point of view.
(3) Because the data are little, the interpretation is not sufficient in this paper. The content of this report is considered to he one example of mechanical stumping of cedar root stock.

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This study is on an investigation on arrangement of branch farm road and tillage road, relation between branch road and field plot, and construction and structure of farm roads.
The branch farm road has a close relation with the field plot and it is decided by the arrangement of the field plot. The field plot on sloping land consists of the contour line side and up and down side. Suitable length of each side of the field plot differs in accordance with the conditions for prevention of calamities and farm practice.
From the view point of the present situation of farm practice, a suitable form of field plot must be decided by taking into consideration the topography of the sloping land and then the management condition.
The form of field plot when considered from the viewpoint of prevention of calamities is maximum contour length of 150-200 meters taken from the limiting length of the same incline of the drainage ditch, and from the point of view of effect of windbreak, the up and down length of the field plot must be about 20 meters for steep slope and more than 50-60 meters for gentle slope.
Good or poor management of farm land is controlled by the slope and shape of the orchard.
Consequently, in order to improve management, uniform rectangular farm plot with the long side situated on the contour should not be applied but must be changed in accordance with the form of the orchard.
Concerning the form of the farm plot, there is the problem of the plot becoming irregular in shape due to bending and crossing of the branch farm road. In view of this, it is necessary to make the farm plot uniform in order to eliminate the obstacles of circling movement and efficiency of machines.
The higher the percentage of tillage road with respect to the main, branch and tillage roads, the saving of labor becomes higher and mechanical operation becomes easier.
From the point of view of farm practice, these network of roads have minimum density of farming, ideal and most suitable density in the present farming situation.
Regarding the construction and structure of farm roads, the higher the density the greater the problem becomes.
Difference in height between the field and road surface can be prevented by improved construction procedure.
The structure of the road surface should be such that side ditch is avoided and drainage belt at intervals of several meters and connected to drains should be provided. By this method, reduction in cost of construction, conservation of road surface and suitable time of management can be expected.
As a result of the above-mentioned investigation, it was possible to find the problems involved. Among these, it can be pointed out that improvements should be made in deciding the field plot for each type of orchard, arrangement of farm roads, most suitable density of farming and conservation of road surface in order to have progress in management of citrus orchards.

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In a previous paper, the authors reported on experiments on farm road pavement using a tar mixture. This paper deals with pavement of farm road using an asphalt mixture and a tar mixture, and deals with properties of the subgrade of farm road. Thepaving methods were as follows;
(A) Asphalt Concrete (Coarse Graded)
(B) Tar Concrete (Coarse Graded)
(C) Tar Concrete (Coarse Graded) with Canvas
(D) Surface Treatment with Tar.
Soil moisture meters (plaster block) and thermistor thermometer were used in order to measure soil moisture and temperature in the subgrade. Earth pressure cells were buried in the subgrade for measurement of earth pressure under a traffic load, and CBR test and Proof-rolling test were carried out after paving to measure the bearing capacity of the farm road. Results show that properties-soil moisture, soil temperature and earth pressure-of subgrade under pavement are different from that which is not paved. The soil moisture of road which has notbeen paved show a large change when compared with that.Lader pavement. The soil temperature near the road surface is higher than that in the inner part in summer and on the contrary lower in winter.
In regard to earth pressure under traffic load, it was indicated that the pavement have a dispersion effect of earth pressure.
Finally, CBR of the subgrade was measured. As a result, it was indicated that CBR is affected by water content and a relation between CBR and water content of subgrade is indicated.
In general, it was shown that pavement of farm road has a good affect upon the subgrade and paving methods (A) and (B) are suitable for farm road pavement.

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Several experimental studies were made on the shrinkage characteristics of clay soils, especially on the effect of the structural changes of these soils with change in the molding water content, and also the effect of the drying temperature (as a rate of drying). Test pieces of soil were molded with 5 different of molding water content and dried at the 3 drying temperatures of 30°C, 40°C and 50°C, respectively. Detailed measurements of horizontal and vertical strains were made and their shrinkage behavior in connection with soil structure was made clear by introducing the new conception of the coefficient of volumetric change.
The results are as follows;
(1) A drying temperature of 30°C did not have such a large effect on the shrinkage behavior but in case of a higher drying temperature, some effect was observed, which may be called the secondary shrinkage.
(2) There was a structural change in the soil test pieces in accordance with change in the molding water content, and its shrinkage constant varied linearly. An increase in the molding water content causes an increase in the shrinkage limit and decrease in the shrinkage ratio.
(3) There is a linear relation between the coefficient of particle orientation, which shows structural characteristic of clay and percentages of cubical contraction by drying. As there is a fixed ratio between percentages of horizontal and vertical shrinkage, it appears that the structural change of clay takes place in an orderly manner by drying.
The coefficient of particle orientation decreases with increase in the molding water content, and it tends to become a parallel orientation.
(4) Results of detailed observation on horizontal and vertical shrinkages are;(a) horizontal shrinkages are mainly caused by pF 2 to pF 4 of soil water, (b) vertical shrinkages begin with the start of drying and a higher molding water content causes a larger vertical shrinkage rate.
(5) From the point of view of the coefficient of volumetric change, there is some difference in the shrinkage behavior due to molding water content in case their horizontal and vertical shrinkage characteristics are the same and have the same parallel orientation. This indicates that there are some quantitative differences among the oriented soil particles.

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The sprinkler system is important in designing sprinkler irrigation, but sufficient studies have not been made as yet on the system.
In this paper, the authors used the Moody diagram as a basis for rationalizing the pipe distribution system for sprinkler irrigation and investigated the limitsof applicability of the Scobey formula and its comparison with the Hazen-Williams formula.
The results are summarized as follows:
(1) The Scobey formula was derived for riveted steel and analogous pipes but this formula is being applied at present to various kinds of pipe.
(2) The Scobey formula is applicable only to pipes having acoefficient Ks in the range 0.2-0.80. For each of these pipes the formula should be used only in the range of Reynolds numbers given in Table 2.
(3) The Scobey and Hazen-Williams formula are respectivelyapplied to the flow of larger Reynolds number and to smaller number, at the smooth pipe side in the transition zone.
(4) Flow rate of 7, 600l/min and the length of line of 2, 400m are considered as the limits up to which the Scobey and Hazen-Williams formulas can be applied. However, these values cannot be considered as basis for the limit of applicability of each formula itself.
(5) It is generally said that the Hazen-Williams formula isapplicable for diameter of over 50mm and velocity over 1.5m/sec but there is doubt in the limit ofvelocity 1.5m/sec.

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The feature of agricutural water works is that a large volume of water is used when compared with other water works. Therefore, modern plans and designs try to utilize it to the utmost. However wate management after the project has been completed is entirely lacking and as a result the work put into this from the planning stage to completion is completely wasted. It is therefore necessary to develop a system of water management so that water is available for irrigation whenever required, irrespective of wet or dry year.
The author developed a method for water management for water source facilities by taking into consideration the features of the water source so that it will match the features of the irrigation areas. If the method proposed by the author is utilized both for new constractions and existing facilities, this can be accomplished simply by modifying and enforcing water management.
For this purpose, the water management of the river systems of Totsu and Kino are explained as examples.
In this river basin, four multi-purpose dams are built for convenience in input and output water calculation but it is necessary to formulate a rule because the problem of how much weight should be placed and the quantity of water released by each dam to the benefiting areas after completion of the project in the future will arise.
For this purpose, 20 dry years were extracted in the order of dryness for a period of 40 years from 1925 to 1961 in the present method and a method of releasing water to satisfy this was decided but the author proposed that a method devised from the standpoint of time series would be more advantageous. That is, the advantage of making it possible to decide resource collecting period of the base years of water discharge from dams or competition for other used (for example, power generation which does not affect irrigation as utilization of water during the non-irrigation period) from continuous water calculation of these periods are explained and as calculation for a large volume of water required for these is possible by using computers, it indicates a method for water management of the water resource facilities in the future.

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Fundamental consideration on the methods of operating dam group, especially on minimizing spill from them is studied in this paper.
Dam groups are divided into three types, namely,
1. Dam group composed of dams arranged in series.
2. Dam group composed of dams arranged in parallel.
3. Dam group composed of the 1 and 2 type.
A single dam was taken as the simplest type of a dam group.
The optimal operational method for each type under the above conditions are as follows;
1. To use stored water from the lower to upper dams.
2. To use stored water by the Space Rule or the Modified Space Rule.
3. To use stored water by a suitable combination of the 1 and 2 method.

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