In order to apply the connected theory of finite element method (FEM) and theory of soil rheology, which was described in our papers No. 1 and No. 2 of this series, to a practical problem, a static sinkage of rigid wheel was taken up in this report.
Representing the soil as a three element model, which has constants E, E₁ and η₁, it was found from the test for a natural sandy loam that these constants decreased when the moisture content of soil increased and they increased with the density.
A FEM program was created to simulate a time-dependent static sinkage of rigid wheel, assuming that a creep phenomenon is found under a constant stress state in a short time interval. A load distribution from the wheel to the soil was always corrected to satisfy the condition of the contact between the wheel and nodes of soil surface.
The calculated values of sinkage by this program coincided very well with measured ones and it would mean the possibility of an application of FEM to rheological interactions between wheels and soils.

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In the previous report, the breakdown of soil when fluid was introduced under pressure into the soil-bed layer in a acryl resin soil-bin, was investigated. It became clear from this experiment that the soil could be broken down easily with a small energy by water jets. This paper reports that a test sub-soiler which injects water from the top in order to break down the soil in front of the sub-soiler, was designed as an application of the results of the previous experiment. The following points were examined; to what degree the draft of this sub-soiler was reduced and to what degree the traction horsepower was reduced. The results of this experiment were as follows;
1. When air or water was caused to flow under pressure into the soil-bed layer (clayey loam with about 15% in moisture ratio) in the soil-bin under fixed conditions of the test sub-soiler, the breakdown of soil as shown in Photo 1 was observed. In this case, the energy with which water broke down the soil was about 1/180 times smaller than that of air.
2. When the energy of the static pressure was compared with that of the kinematic pressure in the total energy required to break down the soil, the former was more than 10 times larger than the latter in either case of the water or air flow. It became clear from this result that the soil was broken down almost by the energy of static pressure (eq. (6), (7)).
3. The type of the sub-soiler in which the nozzle port was directed toward the travel-direction (Photo 3), was of no practical use because the nozzle port become clogged with soil. Therefore, a kind of protector added to the nozzle port was necessary to prevent soil from clogging the nozzle port.
4. The type of sub-soiler in which the kinematic energy of the water jet ejected from the nozzle port was made larger by narrowing the nozzle port to 3.2φ was effective for the breakdown of soil above ground but was quite ineffective below the surface. The pressure produced at the nozzle port of this type was very high and a larger horsepower was required to caused the water to spurt.
5. As for a sub-soiler with more than two nozzle ports (Photo 4), only one of the nozzles around which the resistance of the soil was lowest operated well and the remaining nozzles were all clogged with soil and rendered useless. Consequently, when the sub-soiler had more than one nozzle port, the same number of water pipes with that of the nozzle port were required.
6. Under a constant flow rate of water, in proportion to the traction velocity of the sub-soiler that increased, the draft by injecting water decreased and the produced pressure at the nozzle port fluctuated heavily. This demonstrated that the water worked effectively and broke down the soil when the traction velocity of the sub-soiler was high (Fig. 6, Fig. 9).
7. In this experiment, the draft was reduced to less than half when water of more than about 500cm³/s was injected.
8. When the flow rate of injected water was small and the traction velocity of the sub-soiler was slow, the water hardly broke down the soil but flowed along the surface of the sub-soiler. In such case when the lubricating effect of the sub-soiler by water was seen, the reduction of the traction draft was hardly observed. (Fig. g)
9. The traction horsepower could be reduced because the draft was reduced by flowing water. But another energy was required in order to make the water spurt. The total amount of reduced energy resulted from the balance between the horsepower reduced and the horsepower newly required for the above, was greater in proportion to the traction velocity of the sub-soiler. This reduced horsepower was about 0.33 PS when the traction velocity was 13.6cm/s. Since the traction horsepower of the sub-soiler was 1.09 PS when it was drawn at same velocity without water flow, horsepower amounting to about 30% could be reduced (Fig. 10).
The auther wishes to express his gratitude to the Hokkaido Univer

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Traction test o f driving wheel tire in the field was conducted and some ground-to-tire coefficients were obtained:
1. A rear-wheel-drive tractor has been provided with telemetry instruments with which to measure drive wheel thrust and slip, when the instrumented tractor was pulled from the behind by a braking vehicle when it was operating.
2. Four different wireless signals generated by the instruments were sent out in FM wave from the telemetry transmitter mounted on the instrumented tractor. The signals were received and discriminated at the manless station and recorded in a data-recorder simultaneously and continuously.
3. It was observed that the instrument was durable, showing high resistance against heavy tractor vibration.
4. Some ζ-s (traction coefficient—slippage) curves were obtained with the test conducted on a grassland, asphalt, and concrete. The description of the curves was considered. Either Bekker's or exponential eguations expressed ζ-s curves with practically enough accuracy.
5. Parameter K in the exponential function ζ=ζmax(1-EXP(-s/K)), in which ζmax is a peak of ζ, may be calculated by: K=-s/ln(1-ζ/ζmax) for a set of discrete data of ζ and s, under the restricted condition of ζ<ζmax. And the data within the region υ<ζ<ζmax and s<s: were recommended for calculation, where υ is determined properly according to ζ-s curve and s₀ is the slippage corresponds to ζmax.
6. Parameters in Bekker's and exponential functions and s₀ were called ground-to-tire coefficient.
7. Examples of ground-to-tire coefficients obtained with the test of 12.4/11-36 tire on a grassland, asphalt and concrete were presented.
8. It was considered that ground-to-tire coefficients would not change with the practical change of tire size and wheel weight, when tires were geometrically similar and cohesion between ground and tire was negligible.

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1. Roughness of the field surface, soil hardness and sinkage of tractor wheels were continuously measured while tilling, and the influence of them on low-frequency fluctuations of the tilling torque and the tilling depth were investigated.
2. When the automatic control system was not applied and the height of the three-point hitch wass fixed, the tilling torque and the tilling depth were fluctuated mainly by the roughness of the field surface if the soil hardness was relatively large and uniform. While if the soil hardness was small, they were fluctuated mainly by the sinkage of tractor wheels.
3. When the gauge wheels were applied, the tilling torque and the tilling depth were fluctuated by the sinkage of tractor wheels and gauge wheels if the soil hardness was small.
4. In case of tillage under the automatic control of the travelling speed and the tilling depth, low-frequency fluctuations of the torque and the depth were small. And their correlations to the field roughness and the soil hardness were also small. However, the tilling torque fluctuated transiently when the rotary tiller was lifted and lowered.

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The trouble in the operation of power tiller is the great need of human power. And the desire to be freed of it is a main factor of farm tractorization. The operating power spent by hand lifting of tillage unit and hand steering for turning was examined, considering general patterns of turning operation.
In the case of spring tillage, force needed for lifting of tillage unit was 12-30kg. It had a tendency that the values were in proportion to the dimensions of the body of power tiller.
At the practical tillage in the field, the force is generally lower by the effect of soil reaction than that of stationary state. But it might be said to get higher force than at parked one when tilling depth was shallow, the field was in loose soil condition or some types of tillage blades was equipped. Tilling depth and tilling pitch also gave considerable effect.
Steering force for turning was under influence of running speed, and in a larger turning radius than tread width no steering force was necessary if the rolling of turning-side wheel is hold in check.
As a way for easy turning operation, a mechanical turning device was made which equipped with lifting device for tillage unit and steering device of side clutch-brake system. Using these devices, the RMR value was decreased by 3.0-3.5 than that in human turning.

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In order to lighten the heavy labor of harvesting the lotus-roots by hand, the trial lotus-roots harvester by water jet was built and its performance was tested. The results were summarized as follows.
1. The trial lotus-roots harvester was designed with the object of using on the lotus-roots field flooded with water depth 10-20cm. The main parts of this machine consisted of the boat acted as a float, the jet nozzles doing the fan-shaped reciprocating motion and the pump to suck and supplyw ater, and the machine moved by drawing with wire.
2. In order to havest lotus-roots perfectly, the momentum of water jet per unit area required above 3000kg.s/m² under variable conditions of lotus-roots and field.
3. In order to keep lotus-roots from broken loss under the constant momentum of water jet, other conditions of water jet and velocity ratio of nozzle (=nozzle velocity/working velocity) had to be considered. The desirable conditions of water jet were two nozzles of the inside diameter 28mm, each nozzle pressure 1.8-2.0kg/cm², the discharge mass 650l/min, the jet velocity 18m/s in nozzle outlet and the jet force 20kg. The suitable velocity ratio of nozzle was 20-40.
4. The trial machine harvested lotus-roots at the rate 0.3 a to 0.4 a per hour. The values were 4-5 times in comparison with the rate of 0.08 a per hour by hand.

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A saw chain is one of the most important functional parts of a chain saw machine and various studies have been made, however a vital problem remains unsolved. This report deals with the basic part of the studies on the characteristics of wood cutting force of the whole saw chain used in a chain saw machine. To determine the effects of various factors on the cutting process during chain sawing, a special test stand with devices for measuring cutting and feeding forces and cutting energy was designed. The results were as follows:
1) The mechanism for driving the saw chain unit consists of a three phase induction motor (3.7kW, 2900rpm), a variable speed gear (1:4), and dual V-belt drive system as shown in Fig. 1. By this it was confirmed that the sprocket wheel speed for the saw chain drive was able to be controlled in the range from 1, 125 to 8, 500rpm steplessly.
2) The variable feed rate mechanism for timber cutting has drive parts which consist of a ringcone motor (1.5kW, 125-1, 250rpm), variable speed gear (1:4), reduction gear (1:20), chain and sprocket wheel, bevel gear, and rack & pinion to obtain a linear motion as shown in Fig. 2. From this system, the rise and fall of the table mounted on the saw chain unit can be controlled by manual shift; the raising and lowering comes to total of 500mm at the rate from 1.6 to 60mm/s steplessly.
3) The measuring device was designed to measure tangential cutting resistance force and normal cutting resistance force separately at the timber supporting frame. By this system the measured force was independent of frictional resistance between saw chain and bar rail, and the reaction due to discharge saw dust as shown in Figs. 4 and 5.
The obtained bridge output sensitivities of this two-dimensional dynamometer were 9.134×10^-6/kg (non-linearity ±10%) for the tangential cutting resistance force and 6.516×10^-6/kg (non-linearity ±7%) for the normal cutting resistance force respectively as shown in Fig. 6. Therefore, the sensitivity of the latter was found to be 30% smaller than that of the former unexpectedly.

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The pneumatic conveying experiments of hulls as to specified tube were carried out in our previous report. Energy efficiency at the ejector part was searched from the results and fig. 2 as to flying velocities of the materials.
The mechanism of pneumatic conveying with ejector feeder was investigated in this report. The results were as follows.
(1) The experiment was performed at the condition l_best of which conveying weight became maximum under various distances l between nozzle and ejector. Effective conveying energy P_s was in direct proportion to W and the value of W/P_s were constant at any conditions beyond the ejector (fig. 3). The values of W/P_s were small at the conditions except l_best.
(2) Energy efficiency η was defined as a ratio of supplied energy P_f to energy P_s for conveying. The value of η became maximum at the opening ratio (D_d/D_n)_best that the value of W was maximum.
The values ranged from 0.30 to 0.40 at conveying nothing but air, and ranged from 0.19 to 0.30 at conveying air and materials.
It was recognized that the value of η became larger according to decrease of static pressure h_f. The relation was clearer at conveying air and materials (fig. 4 & 5).
(3) Air flow Q_a for conveying was maximum near the (D_d/D_n)_best η was, The Q_s had positive correlation to h_f and diameter of nozzle D_n. Balances of Q_a and supplied air flow Q_f were almost positive at conveying nothing but air, while were almost negative at conveying air and materials (fig. 4 & 5).
(4) Although effective static pressure h₂ beyond the ejector showed larger fluctuation at conveying air and materials than at conveying nothing but air, they were seemed equal at the practical conditions that D_n was large. Effective static pressure h₂ was maximum near the (D_d/D_n)_best as W, η and Q_a were, and it had positive correlation to h_f and D_n (fig. 4 & 5).
(5) Effective static pressure h₂ was equal to the flow resistance between Q_a and W. In the case of conveying nothing but air, it was recognized that h₂ was in direct proportion to square of Q_a (fig. 6). The h₂ had cross-correlation to Q_a and m as fig. 7 showed, and the relation was represented by equation (5). But in the case of conveying air and materials, a large fructuation was observed in the tendency. This means the eq. (6) which represents pressure drop β can be transformed into eq. (7).

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The objective of this study was to find out the relationship between separating performances and physical properties of grain, using a shaking separator of which frequency and feeding rate were 240cpm and 200kg/h respectively. The difference of size and frictional coefficient of grain might be principal factors related to separation of the grains, and a feeding material used were trimmed with a combination of processed grain and some kinds of grain. And the separating performance in the range of the discharge end would be illustrated with the value of recovery and Newton's efficiency.
The main results were as follows:
1) When both the difference of the frictional coefficient and that of the grain size in the feeding material were nearly equal to zero, it was quite impossible to get the desirous grains and tailings in the discharge end separately. Therefore, the value of Newton's efficiency was zero. And it is clear that there is also no separating possibility when only the difference of the frictional coefficient of grain is in a feeding material.
2) When both the difference of the frictional coefficient and that of the grain size in a feeding material were larger than zero, the recovering of the desirous grain and tailings was very easily practicable in the upper and lower portion in the range of the discharge end separately. It is tendency that in this case, the value of Newton's efficiency increases proportionally with the increase of the range of the discharge end, and it arrives at the peak value, and then it gradually decreases. Generally speaking, the increase both the difference of the frictional coefficient and that of the grain size among grains makes the value of Newton's efficiency increase.
3) When only the difference of the grain size in a feeding material were larger than zero, the value of Newton's efficiency was considerably higher.
4) In the case of the separation of grain using the shaking separator, the difference of the grain in a feeding material might be induced the segregation of grain, and that of the frictional coefficient of grain might be induced the movement of grain on the separating surface. It is clear that the separating performance of the shaking separator is materially improved by the action of above these factors.

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In order to investigate the viscoelastic property of a rice kernel, the compression and the stress relaxation tests were made by using the test pieces of the rice endosperm formed into a cylindrical shape. The experimental results obtained were summarized as follows:
(1) The beginning of the stress-strain curve obtained under a constant strain-rate compressoin test was given as a convex function due to imperfect contact between the end surfaces of the test piece and the loading plates.
(2) By the stress-strain curves obtained under various strain-rate tests, it was found that the strain at a constant stress level had a tendency to increase with decreasing strain-rate. It could be considered, as a result, that a rice endosperm had a viscoelastic property.
(3) By the stress relaxation tests, it was proved that a compression stress in the rice endosperm was remarkably relaxed with time.
(4) It could be concluded that the rice endosperm was approximately a kind of linear viscoelastic materials in the range about ε<1% or σ<2kg/mm². The relaxation property of the rice endosperm was given by the following equation, E(t)/E(0)=0.3exp(-t/τ₁)+0.7exp(-t/τ₂) where E(t): relaxation modulus, E(0): instantaneous elastic modulus, t: time, ε: nominal strain, σ: nominal stress, τ₁ and τ₂: relaxation times.

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In this paper, the authors introduced an analytical solution to obtain the drying rate on the fluidized bed drying of high moisture rough rice, particularly from the view point of pre-drying. Both observed and calculated values were compared. Consequently the propriety of analytical solution was found. The main results were as follows.
1) Analytical drying rate equations were developed based on the following assumptions. (Eqs. (16), (17)) (i) The relation between equilibrium moisture content of rough rice and relative humidity is approximated by a linear function. (ii) The moisture content of rough rice is uniform in the fluidized bed. (iii) The pattern of air flow in the fluidized bed is piston flow. (iv) The drying rate equation for the period of the first falling rate is applied in this analysis.
2) The large drying rate of early drying period was shown clearly in the drying curves. Therefore the drying process was devided in two periods. The coefficients of drying rate for each period were obtained based on the drying curves. (Eqs. (20), (21))
3) Close agreement between observed and calculated values was obtained after the consideration on the coefficient of drying rate.
4) The drying rate of rough rice was considerably affected by air temperature and independent of air rate. While the higher initial moisture content of rough rice was slightly larger drying rate.
5) This analytical solution could be calculated simply, giving only the values of air temperature, air rate and initial moisture content of rough rice as the drying conditions when atmospheric temperature and humidity are measured. Therefore the solution may be useful as the base of planning and operating the pre-drying apparatus of high moisture rough rice by fluidized bed.

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An air transportation test from Naha to Tokyo was carried out to improve the technique during the distribution process of Sayaingen (immature kidney bean with pod) produced in Okinawa.
The changes in the temperature and relative humidity during transportation included the flight were measured. The following results were obtained:
1. The relative humidity in DV type freight container loaded Sayaingenn was about 95% R. H. in maximum.
2. In air transportation, dew may well develop by the different weather conditions between origin and destination.
3. Under high humidity condition in air freight container, the strength of existing shipping carton was reduced.
4. Atmospheric pressure in the cargo compartment during flight was 8.3×10⁴Pa in minimum. Changes in atmospheric pressure may be affected the respiratory evaporation of fruits and vegetables and humidity in freight container.
5. The air freight container such as DV type was unsuitable for shipment of the fruits and vegetables because DV type freight container was more air tight than 20 footer ISO type refrigerated marine freight container.

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The melting phenomenon of an ice sphere placed in a constant temprature box (moist air temperature: 8-21°C, relative humidity: 77-90%) was researched assuming that an ice bunker is used in free convection cooling type cold storage warehouse.
The summary of results were shown below.
1) The mass of an ice sphere was almost decreased with time (Fig. 2).
2) When an ice sphere was melted in free convection, the heat and mass transfer coefficients were approximately expressed by the following equations.
Nu=2+0.40G_r^0.27P_r^1/3
Sh=2+0.40G_r^0.27S_c^1/3
3) The mass of water vapor condensed to an ice sphere was able to calculate by equation (26).
4) The total heat transfer rate to an ice sphere was able to obtain as the algebraic sum of heat transfer rates by free convection, radiation and condensation. Each heat transfer rate was roughly equal through the section A-B of Fig. 2.

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In the preceding paper, the basic characteritics of the new soil sterilizing method in which soil was sterilized by the heat transmitted from the radiating pipes buried in the soil were clarified. The outline were as follows: The lethal temperature of main soil borne pathogens of indoor horticultural crops was 60°C. And initial air temperature and air velocity following in the radiating pipe of 10cm diameter, 20m length were 120°C and 8 to 10m/s respectively. In the present paper, various problems regarding the design of sterilizing device was discussed and also, results of trial production of the device and field experiments were detailed. These results are as follows.
In application of commercial greenhouse heaters to the soil sterilization a number of problems to be solved were found. These were as follows: 1) insufficient adiabatic processing of the heater shell plate. 2) shortage of the wind power of fan. 3) lacks of air exhaust port numbers. 4) uniform temperature and velocity of heated air between increased ports. 5) mobility of the heater.
The air heater for soil sterilization was fabricated. The brief specifications and outline drawing are shown in table 4 and figure 1. The results of experiments on the practical scale were as follows.
1) The fusarium wilt with cucumber died completely with treatment of 60°C during 10 minutes. 2) As a result of the experiments on the effect of the sterilization on the growth, the yields and the weed controls, the satisfactory results were obtained respectively. The comparison of the cost analysis of the heated air method and steaming method was investigated. The total cost including the depreciations of air heater and other instrument in this method was equivalent about 58% to the steaming method.
The new system of soil sterilization developed by the authors was considered to have reached the stage for practical use.

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Gradings of fruits and vegetables depend on the sensory perceptions of sorting persons, and the judgements of the grades are different among ones. The sorting persons, therefore, learn the grading standard with due regard to the management plan from the leader and are trained for the accurate grading. To the meeting for such education or training on the grading is given the term of “Mezoroekai”. This meeting often holds at the packing house in the harvest season. In this paper the effects of “Mezoroekai” on grading of Kaki (Diospyros Kaki L. cv. Fuyu) were investigated. The results were follows:
1. By Mezoroekai, concordance of psychometric scale for grading among sorting persons in the same packing house was improved, and fluctuation of criterion point on psychometric scale significantly became small up to certain range. Such effects had continued after a week from Mezoroekai.
2. Criterion points of sorting persons could be changed, but returned to one's previous points nearly within a week from Mezoroekai. This means that the criterion point is of one's own and it is consequently apt to return to own point even if it can be changed by the present Mezoroekai. On the other hand, individual difference on criterion point could not be made uniform by the present Mezoroekai.
3. Rigid or economic grading was proved by criterion point, and extreme rigidness seems to cause much inaccuracy to the grading.

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Computer simulation runs of the hay production system with a conventional hay baler, the hay production system with a round baler and the hay and silage production system with a round baler, which were assumed as a forage production system for being operated within an individual farm scale, were carried out under the weather condition of three regions, Sapporo, Watsukanai and Kushiro. The results were as follows:
1) Suitable operating area for the hay baler system was 17ha at Sappro and Watsukanai and 15ha at Kushiro. Harvesting area per day should be limited 4ha, 2ha and 2ha at the respective regions. (Table 3)
2) Suitable operating area for the round baler system producing hay was 37ha at Sapporo, 40ha at Watsukanai and 30ha at Kushiro. A limit of harvesting area per day was 2ha, 6ha and 2ha, respectively. (Table 4)
3) Suitable operating area for the hay and silage production system used a round baler was 42ha at Sapporo, 49ha at Watsukanai and 37ha at Kushiro and harvesting area per day should be limited 2ha, 4ha and 2ha, respectively. Wilted grass silage production at Sapporo, Watsukanai and Kushiro was 7.6, 4.0 and 9.6 percent of the total production. (Table 5)
4) The larger harvesting area per day causes the larger operating area and the lower productivity of high-quality hay.
5) The round baler system has higher ability to produce hay than the hay baler system has. The round baler system supplemented by wilted grass silage production has much more suitable operating area and dry matter productivity, but it has the lowest productivity on high-quality hay of the three systems.
6) High-quality hay productivity of the hay baler system is higher than the round baler system. The hay baler system has more high-quality hay in the first cutting than in the second, but on the other hand high-quality hay in the round baler system is more in the second cutting than in the first. On the hay baler system, there is hardly difference of high-quality hay productivity between the three regions. On the round baler system, however, the productivity is slightly higher at Watsukanai than at Sapporo and the lowest at Kushiro.
7) The highest dry matter productivity is gained at Sapporo and the following region is Watsukanai.
8) In general Watsukanai is the most suitable region for hay production of the three regions and Kushiro is the worst. However, if limited to the hay baler system, Kushiro is about the same as the others.

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