Tests were carried out using six different models of rakedozers to determine the cycle time of the clearing work. The following results were obtained.
1) The forward speed under load on an even ground decreases with increasing load when the forward speed under no load is taken as the standard. This relationship is shown in Table 5.
2) The forward speed under no load on a descending slope increases with increasing gradient. This relationship is shown in Table 6.
3) The forward speed under load on a descending slope decreases with increasing gradient when the forward speed under no load is taken as the standard. This relationship is shown in Table 7.
4) The backward speed on an ascending slope decreases with increasing gradient or the backward motion becomes impossible. This relationship is shown in Table 8.
5) The cycle time of the clearing work was expressed as C_m=C_td+t, and the cycle times on an even ground and slopes were calculated as shown in Table 9 and 10.
6) It is not easy to show the cycle time of the clearing work under varying conditions accurately because of complexity of the factors involved. The findings reported in this paper will be useful in the area of mechanical reclamation.

View full abstract

Authors studied evapotranspiration of red clover for five years with floating lysimeter at Sapporo, Hirosaki, Tokyo, Gifu, Shiga and Tottori. In this paper, the relation between evapotranspiration and climatic factors is described. Results are summarized as follows.
1) When the relationship between evapotranspiration (ET) and one of the climatic factors was studied, amount of sunshine (R) was found to be the best factor. equation (2).
2) When amount of sunshine (R) and average temperature (θ) were combined, closer relationship was observed. equation (3).
3) The relationship between ET and evaporation of evaporimeter (E) was not so clear, but when it was combined with θ or R, closer relationship could be observed. equation (6), (9).
4) If saturation difference (Δp) was given, ET could be estimated by combination of Δp and R. equation (8).
5) The proportion of calory consumed by ET to the amount of sunshine, was correlated with θ and Δθ.(i. e. the difference of the ground temperature at the depth of 5 cm and 20 cm.). equation (11).

View full abstract

For five months, from April 21 st to September 27 th 1967, in Kusatsu City where is in the inland region of Japan, we measured the evapotranspirations (ET) of the red clover by using lysimeters.
When the soil is wetter than pF 2. 5, the major variables affecting ET are temperature, pan-evaporation (E) and radiation from the sun measured by using a Robitzsch pyrheliometer (R_s).
1) The relations between temperatures and ET (see Fig.1 to 3) are expressed by the empirical formulas (1) and (2). Where “e” is the daily mean ET in millimeters for a period of ten days. The value t_max or t_m are the mean daily maximum or mean temperatures in Centigrade for a period of ten days.
2) The monthly mean values, ET/E were 1.07 in May, 1.16 in June, 1.45 in July and 1.29 in August. Figure 4 shows the relation between the accumulated values of ET and E. ET is proportional to E during adjacent harvest time.
3) ET/R_s have almost the same values as ET/E, and were O. 80 in May, 1.10 in June, 1.10 in July and 1.25 in August.
The growth of red clover during the period of experiments was normal in May and June, but it declined after a lot of rain in July due to insect injuries and the development of plant diseases. Therefore, the leaf area index (LAI) of red clover in July was reduced to about half of the LAI in June as shown in Table 2.
After July, ET also decreased a lot. We showed the computed values of ET by using Blaney-criddle's method (K=1.00, U) and Taneda's method (e') in Table 2.The table also shows possible LAI calculated under the assumption that ET is proportional to LAI and that LAI in May was normal.
Table 3 show the ET and LAI of red clover measured by using floating (soil tank 1.2 m×1.2m, 0.9 m depth) and portable (soil tank 0.56 m diameter, 0.9 m depth) evapotranspirometers. Potential evapotranspiration PE was measured by maintaining the soil moisture in the soil tank above pF 2.5. The same was done with ET of the floating. In general, the growth of red clover in the portable was thicker than in the floating. Therefore, PE in the portable was larger than ET in the floating.

View full abstract

Land valuation by means of marks allocation is a method for deciding substitute lots for the purpose of grouping of farm land. But this method when applied to paddy fields gives rise to many problems. The objective of this paper is to investigate the feasibility and practicability of this method of substitute lots decision when applyed to the grouping of paddy field. As a result of this study the method for deciding substitute lots according to a definite order is proposed here as a new method for the purpose. As a first step in this study, the factors affecting the effectiveness of labor in the paddy fields are examined by presuming that the factors affecting the productivity of the land are more or less constant.
With the function formed from these factors, the condition of the paddy field of each farmer is then expressed. It is my opinion that the function Σl_i, namely the summation of the distance from one's farmstead to each lot, obtained from this study is the most suitable function for this.
This function is set on an order of increasing magnitude, and the substitute lots are then decided according to that order.

View full abstract

The design of the substitute lots on the region of Sanpohjima and Kariya Hazama-choh Tome-gun Miyagi-prefecture is made by applying the substitute lots deciding method proposed in the former paper (I).
Fig. 2 is the outline map of this region. Fig. 3 is the map of the design of the substitute lots of this region.
The hearing investigation on the scene is conducted on the dasis of that design. The findings of this investigation are arranged in Table 1. Almost all the opinions which were expressed in this investigation are that “I have nothing to complain of about this design” or “This method for deciding substitute lots is rational”.
The farmers who expressed their dissatisfaction at this design are persons whose substitute lots are in poor drainage areas or liable to be damaged by flooding.

View full abstract

The writer previously proposed an impact model of the snowslide, useful for the various snowslides in cold or warm weather. In this paper, he discusses how to apply the above model to the landslide, which is very similar to the snowslide.
That is:(1) He points up the similarities and the differences between these two phenomena.(2) He illustrates the representative impact type of landslide, omitting a definition of the slip plane.(3) He estimated analytically an example of the slip plane in homogeneous ground from the shear strength depending on the water contents, in the case where water is diffused from the ground surface.

View full abstract

For the study of effective utilization of rainfall, experiments were conducted with various levels of irrigation coordinating two kinds of soil at depths of 10, 20 and 30cm.
The results observed were as follow.
1) On the case of a shallow irrigation system of 10cm soil depth, the soil moisture of the deeper layer was heavily utilized, because the capillary moisture moves upward. Therefore, as the deeper soil layer has less moisture, rainfall was effectively stored there.
2) From the relation between the soil moisture and root distribution, it was found that the absorption of the moisture by upland-rice was conducted near the surface layer, within a depth of 10cm.
3) The best irrigation system in which the rainfall was used most effectively, and irrigation water was most available for the plant was with irrigation at a depth of 10cm.
4) Considering soil of quite different composition, the utilization rate of rainfall or irrigation water of Kamigamo Soil with more available soil moisture was smaller than that of Kyodai Soil with less available soil moisture.
5) Comparing the utilization percentage of rainfall on different groups of soil having different available moisture, it was found that soils having higher available moisture are more advantageous with regard to moisture utilization than that of soils with less available moisture. This is particularly evident in the case of the soil layer at a depth of 10cm, compared with the other depths for irrigation.

View full abstract

This paper is composed of three parts, the first one is a hydraulic head calculation method for a pipe-line water distribution system, the second and the third are the examples of its applications.
In the first part, the equations expressing hydraulic characteristics of a pipe-line water distribution system are rearranged and the calculation method of hydraulic head suited to approach for an opptimum water distribution system is deduced. Its comvergence in iteration process is improved by combining the two linearizing methods. Then it is pointed out here that the coefficient matrix or its inversed one in this method of calculation are very useful to evaluate the system's characteristics.
In the second, some quantitatative evaluation methods of hydraulic head response to the outflow rate fluctuation at nodes, is deduced from the above mentioned calculation method, and it is verified with these evaluation methods that a net-type system generally has more absorption capacity of head fluctuation than a tree-type or a comb-type system.
Lastly, it is explained that the energy for water distribution is analyzed into three components; friction loss, caused by the water distribution system only, potential energy of water, caused by the topographical undulation of the object region and pressure regulation loss, caused by both the distribution system and the topographical character. The methods to determine the injection rate assignment to minimize total friction loss and the amount of friction loss and pressure regulation loss in multiple injection systems are also mentioned. In this discussion the above mentioned method of hydraulic head calculation plays an important role.

View full abstract

Since nearly all sprinklers are sprinkling over circular areas, a certain amount of overlap is always necessary for uniform water distribution.
The degree of the uniformity of water distribution in the field can be expressed numerically by the index-Uniformity Coefficient (C_u) which is defined by the equation C_u=100 (1.0-ΣX/m·n).
This index is an important factor for planning and controlling the sprinkler irrigation system and has been evaluated from such experiments as the Pan tests and the Can test.
In this report, the authors propose a method of calculation to evaluate the Uniformity Coefficient from the distribution pattern formed by a single sprinkler and to use an electronic computer in order to process this calculation.
Then, an optimum spacing for a certain sprinkler discharge profile and an optimum sprinkler discharge profile for a certain spacing are studied by using this calculation technique.
These data and the proposed calculation technique may be very useful for the planning and control of a sprinkler irrigation system.

View full abstract

The current need for more intensive utilization of land in Japan has called for greater flexibility in its use by transforming paddy fields into farm land and vice versa at one's option.
So, the crucial problem of subsurface discharge is receiving particular consideration.
The authors have been investigating subsurface discharge in a paddy field by using it as farm land for a few years. The last report discussed in detail the relationship between the rainfall and the subsurface discharge based on results from the test paddy-field of the Takatsuki Agricultural Experimental Station of the Kyoto University.
As the result of this, it is evident that the amount of subsurface discharge could be estimated exactly for practical purposes if the rainfall pattern and the pan-evaporation were known.
In this paper the authors have derived the basic equation out of dynamic and water balance equation. And then they explain the physical meanings of the unit graph method by adapting the Maasland's theory to it. Then they get a unit graph from the observation data on drain discharges from independent rainfalls observed at this field for some years.
The subsurface discharge is also estimated by adapting this method to the observed efficient rainfall.
In the results the calculated values agreed well with the observed ones on peak discharge and the time lapse especially for the peak discharge. Therefore they can say that this method is an useful means for analyzing subsurface discharge.
Finally, it is clear that the long period of subsurface discharge could be estimated exactly because the initial rainfall loss could be estimated by using water balance.
Making good use of these conclusion for the planning of underdrainage is necessary after some period of observation of the subsurface discharge, the rainfall and the pan-evaporation to formulate the coaxial figure on the relationship between the amount of rainfall and the subsurface discharge and to prepare the unit graph.
And still more, it has been proved that instead of the coaxial figure the polynominal equation can be adapted as well.

View full abstract

When a dam is built in a river, the earth and sand from upper stream is prevented in movement at this point by settling. And thus, the flow into a down stream is reduced, leading to the lowering of river bed. To deal with the problem of estimating the final river-bed equilibrium, there are two methods based on stationary and dynamic equilibrium theories respectively. Utilizing these two theories, a calculational method based on a mathematical model is presented for the equilibrium river-bed level after a change in the sediment supply. In this method, use is made of the friction velocity and uniform flow depth at the reference point corresponding to the position of river bed under investigation. Then, in estimating in the extended section of a river bed, the employment of the following two are proposed. It is first the division according to the existing, longitudinal slope of river bed, and second the use of average river width and uniform flow depth at the respective reference points, over the whole section, derived from the widths and the average friction velocity, in order to reduce the local error. In the determination of a stream flow to control the equilibrium river-bed slope, the “dynamic” slope differs little with the stream flow, but this difference is fairly large in the “stationary” slope. A variety of the stream flows are thus inserted in the stationary slope formula, to give the most suited flow stream to an actual river. Some examples of its actual application in rivers are also given.

View full abstract

Generally speaking, it is not seemed that the shape of granular material with comparatively large grain diameter used in the civil engineering works has been treated as an important factor, though the shape of civil engineering materials has effects on the strength, durability, difficulty in construction works, of the structure. There are several reasons of the aboves, the authors consider. One of these is based on the fact that considerable amount of labour works are needed to measure the shape of granular material by means of the conventional measurement methods. And the other reason is that the results of measurements themselves generally represent only the shape characteristics of individual particle, but not of the aggregate materials which are consisted of many particles with various sizes.
In this paper, using the conventional direct and indirect methods for measuring the shapes, the authors investigate the shape coefficients of the aggregate materials by basing on the results of measurements obtained in the particles of sand and gravel under the following three conditions;
(1) Particles being deposited with parent rocks.
(2) Particles suffered abrasive operations through their transportations.
(3) Crushed stones.
From the above measurements, the following facts were confirmed;
(1) The surface roughness and geometric anisotropy of the particle are two independent parameters, both of which should be used to represent the shape coefficient.
(2) In the aggregate materials, the shape coefficient is affected by the degree of surface roundness of the material.
Depending on the aboves, the authors consider that in relation of the degree of roundnees the aggregate characteristics such as the void ratio and substantiality under a fixed condition are the factors which represent the shape in the aggregate materials and indicate the effect of the surface roughness. As to the geometric quality of materials that is the other parameter, the direct sphericity and flatness are reasonable to be used as the factors indicating the geometric quality. Therefore, the authors analyzed the experimental results and obtained the following capacity coefficient (C), which can be easily measured,
_??_(1)
Where, V_n; volume of the particle, N_m-1; diameter of mesh through which the particle can pass, N_m; diameter of mesh through which the particle can not pass.
Because the capacity coefficient is a factor to indicate the anisotropy in the shape, it is considered that this coefficient can be used as a standard in the selections and classifications of the construction materials, in combination with the void ratio which tightly correlates with the degree of roundness.

View full abstract