(1) The authors produced a weeder for waking tractor. The field capacity of the weeder is as follows; working width is from 600mm (common use) to 1000mm (maximum use) and working depth is from 10 to 30mm. Short-teeth and long-teeth are installed on three beams. Interval of the tooth-mark is 12.5mm in case of the combination of short-teeth and long-teeth and the value (12.5mm) is very small. In case of long-teeth (or short-teeth), the interval is 25.0mm.
(2) The power is less than 0.7ps when working width is 40cm and it is effected more by working speed than working depth (1cm or 2.5cm) and interval of tooth-mark (1.25cm or 2.50cm). The draft resistance of one tooth is about 0.3kg and the maximum resistance is 0.7kg. The uint resistance is about 0.7kg/cm² in loam and about 0.2kg/cm² in sandy loam.
(3) The larger the working depth is and the more the working strokes are, the deeper the crushing sphere is.
(4) Value of level degree (80%) after the working is from 15 to 20mm.
(5) Pulverizing effect by the weeder is noticed merely when the field is dry slightly. The proper pulverizing condition of field-surface is as follows; the weight ratio of clods smaller than 1cm and ones larger than 1cm is“7:3”.
(6) Clods on the field-surface move rather far away and distance of the moving clods by one rank of teeth is about 5cm.

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The traction performance of tractor pulling the load at the hitch point which has lateral eccentric length from the center of driving axle was studied. In this study the case of the same weight on each side driving wheels was dealt with.
The tests were divided into two sections in the same way as the previous reports (1)-(3).
1) When the test tractor is pulled by another one, eqs. (1) and (2) shown in report (2) are applied to this condition, replacing λ (ratio of weight difference) with l'/l (eccentric ratio), where l is a half of tread and l' is eccentric distance of hitch point from the center of driving axle. And A and l' are denoted in plus value, under the conditions of heavier outside wheel and inside eccentricity toward the running direction respectively, and yet inside is denoted the direction giving reflection angle.
2) When the tractor is pulling some load, traction force P and side force Sp (n) are denoted by the same equations shown in report (2), replacing λ with l'/l. The driving force is also dealt with in the same way.

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The authors designed the one row ratooning machine of tractor rear-mounted type. Although the design was made on some assumptions, the machine worked well on a sugar cane field in Indonesia. The results are as follows.
1) Stubbles of sugar cane can be cut by the rotating rigid knives with curved point. Its diameter of rotation is 700mmφ, the revolution speed is 1060 r. p. m. and peripheral speed is 35-40m/sec.
2) Required horse-power for stubble cutting was 8-9PS.
3) The suitable length per one knife was 6-9mm
4) Inclining the cutting knives against the ground was necessary to consume the least horse-power for rotation. The inclination of 5°was most suitable.
5) When the machine is used in a dirty field with scattered sugar cane leaves, the ridging disc blades do not penetrate easily. And some additional weight or detaching the discs may be necessary to overcome this condition.
6) Coulter wheel rim is necessary to prevent the swing of machine in work.
7) Center rotary shaft must be shielded to protect from winding leaves.
8) Adjusting the cutting height must be done from the driving seat.
9) Capacity of this machine was estimated as about 2.8ha/day.

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This paper discuses the relations between the factors of operating time and the various tractor utilizing types. The tractor utilizing types can be classified roughly into four types; the family farm use, the co-operative farm use, the work partnership type and the custom-work type. The sample farms of eachtype were selected from the dairy farm in Hokkaido. The operating procedures and handling methods of their tractor were investigated through the season by the service-recorder mounted on the tractors.
The results from the records are as follows:
1) The operating days are from 75 to 80% of investigated days, and the percentage is much the same value as the percent of dry days suitable for tractor work during the season. The value has a little difference between the types.
2) The operating hours a day vary greatly by season and utilizing type. It may be mainly changed by the covering area and the need of miscellaneous works besides the tractor work. In the family farm and the co-operative farm, they scarcely operate the tractor over 8 hours, since they have much side-works. In the custom-work and the work partnership type the operating time often exceeds 9 hours during the busy season.
3) The operating time includes the working time and the lunch time, and the latter is usualy about 90 minutes in most types. The working time can be classified in to the acutual field work, the arrangement, the traveling and the rest time, and their mean values are 68, 14, 10 and 8%, respectively. The difference of the values between the types cannot be recognized clearly.

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Pipe dusters, which consist of the duster and the perforated dust head (hereinafter reffered to as P. D. head) made of 20-100 meter long soft vinyl pipe, diffused owing to the cheapness and the high rate of work. However, many poisoning accidents, which depend on the wrong usage and defects of the P. D. head, were caused in various parts of the country, in the summer of 1967. The main defects of the P. D. head are the following two items.
1. Dust chemical settles and accumulates on the halfway in the P. D. head. Since the end of all P. D. heads on the market is closed, the decrement of the penetrating wind velocity is remarkable, and the dust chemical deposits on the halfway with elapsing of the application times.
2. The length of the P. D, head is unable to be controled. When the application width is narrow because of shape and width of the paddy fields, the P. D. head must be cut at the base near the duster, in stead of rolling the end, because the outlet perforations are distributed to suit for the full length application.
To make up for the defects, we propose in the report to open the end and to set a dust collector such as a cyclon separator to the end of the P. D. head. (Fig. 1) Then we examined Some tests which are necessary to the P. D. head for the uniform application, and searched how to express characteristics of the P. D. head.
1. In case of expressing the characteristic of a P. D, head itself without the influence of the fan, it is easy to understand if index number of wind velocity is used (Fig.2)
2. By plotting the static pressure and the penetrating air flow per minute in the P. D. head on a rectangular coordinates, the characteristic of a set tied up with a fan and a P. D, head is expressed considerably well. Namely, the condition of the stream at any parts in P. D. head can be seen clearly.
Besides, the limits due to the material of dusts and P. D, heads are expressed on the same graph. (Fig. 3)
3. According to the performance curve, in the Preceding graph the wind velocity beyond the midpoint of the P. D. head with closed end falls under the lower limit of wind velocity to convey the dust. On the other hand, opening the end to its full section bring about better results, but the floating force of P. D. head, that is the force blowing into the crop plant, become weak near the end. For the best, the opening area of the end is required to be about a half of the full section, in order to keep the appropriate static pressure (Fig.4).
4. By means of opening the end, the performance curves of some P. D. heads (E & F) are improved. The other P. D, heads require further examination not only about the opening of the end but about the length, the diameters and the outlet interval.
5. The penetrating wind velocity must be kept at 15-20m/sec even at the end, so as not to de posit the dust. (Fig. 5)
6. For preventing the deposition and achieving uniform application, it is desirable that the dust chemical is applicated as thin as possible.
7. The direction of the discharging wind incline toward the end. The tangent of the inclination angle is nearly proportional to the ratio of penetrating and discharging wind velocities. But the inclination angle is not over 45 degrees. (Fig.6)

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Since the small dismembrator is often used for grinding crops and others on the farm, the authors investigated its characteristics on unpolished rice. The following results were obtained;
1) The power required for grinding is directly proportional to the feed rate, and inversely to both an exponential function of rotor revolution and to the diameter of screen holes.
2) The specific surface of products is affected by the diameter of screen holes, but is unrelated with the rotor revolution and feed rate.
3) The optimum revolution and diameter of screen holes increase with the increase of feed rate, and are considerably larger than those of specifications.
4) Within the range of rough grinding, the work is proportional to the specific surface of products. The above fact accords substantially with the previous data.
5) It may be accepted as a fact that the critical limit of specific surface is in existence.

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In order to increase the rate of cell-filling in planters, experiments were carried out under laboratory conditions.
It was found desirable that soybean seeds would move in the following way (1) beans in the seed hopper will move smoothly in vertical direction, (2) beans which are in contact with the seed plate will be readily pushed forward to the outlet, and (3) beans will roll on actively in the inlet area which is within about 5cm from the end of the pawl cap.
The results of the present studies were summarized as follows:
1. The friction between beans and the seed plate exerted the greatest influence on the movement of beans.
2. The force of friction was determined by the following three factors: the moisture content of beans, the linear speed of seed plate, and the depth of piled seed covering the seed plate.
3. The above factors which determined the seed movement interacted on one another.

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(1) Soaking of the seeds of soybean, dwarf red cranberry and white kidney considerably accelerated their rehydrations.
(2) Above 15 hours there was no difference between the moisture contents of the first soaking beans and the second soaking beans.
(3) The rehydrating curves of dwarf red crauberry and white kidney are similar to each other.
(4) The light micrographs of the beans embedded in epoxy resin showed that the cell of dwarf red cranberry was similar to that of white kidney in the shape of sphere, and the cell of soybean was ellipsoid of rotation.
(5) In the cases of dwarf red cranberry and white kidney, the start of diffusion of water through the second soaking beans is about 30 minutes earlier than through the first soaking beans.
(6) The contents of beans suggest that the carbohydrates may cause main resistance to diffusion of water through beans.
(7) The large rates of rehydration of the second soaking beans were reduced rapidly, whereas those of the first soaking beans kept small.
(8) On the maximum rate of hydration, the rates of the second soaking beans are about four, times those of the first soaking beans.
(9) Because the rehydrating data which were plotted on semilogarithmic graph paper yielded straighterlines, it is suggested that the rehydration has a connection with the adsorption.
(10) The deterioration will have to be taken into consideration in common warehouses, since it is estimated that the storage life of the beans harvested under the continued rainy weather may be reduced.

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T. E. W. Shumann (1929) presented a differential equation for the heat transfer in packed bed assuming that there was not hermal resistance within the products, and gave a solution for the case in which the constant temperature of the inlet liquid was constant.
C. C. Furnas (1930) developed the solution in the form of the simple integral containing the zero order modified Bessel function, and the solution has been applied generally for problems in chemical engineering and agricultural process engineering.
However, in the case of fast precooling of farm products, the solution seems to be inexact because of small thermal conductivity of the produts and variable inlet cooling air temperature.
In this paper the Shumann's equation was solved for the exponentially dropping inlet air temperature, and gave the analytical solution to the Sugiyama and Nagasaka's equation which was derived with regard to the thermal resistance and the temperature gradient within the products.
Comparing the calculated values by these three solutions with the same cooling curve of packed bed of eggs, the following results were obtained:
1. The calculated temperature of the Shumann and Furnas's solution was lower than the average measured temperature.
It was mainly caused by negrecting the thermal resistance within the products and the variation of the inlet air temperature.
2. The exponet-approximation method agreed satisfactorily with the measured values, but it was difficult to estimate the variation in inlet temperature. This method had a possibility of simplifying methods of measuring the heat transfer cofficient in packed beds.
3. The Sugiyama and Nagasaka's method agreed satisfactorily with the measured surface temperature of products, but was inconsist with the initial condition with regard to the center temperature.
The agreement could be improved by multiplying the exponential term in the analytical solution by a constant.

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This report presents information on the design and construction of an experimantal portable vacumm precooler. The precooler is a prototype designed to test the feasibility of commercial use in vegetable and fruit fields.
The prototype was designed by the Food and Agricultural Engineering Laboratory, Faculty of Agriculture, University of Kagoshima, Kagoshima-shi and constructed by Hitachi, Ltd., and Hitachi Construction Co., Ltd., Tokyo.
1) The prototype portable vacuum precooler consisted of three basic components: a vacuum chamber, a vacuum pump, and a condenser. The equipment was mounted on a wooden frame so that it could be moved to any where by a 6.115-meter-long, 3.5-ton track. It was 1.8m. wide, 2.05m. high, 4.5m long and 3.5 tons in weight.
2) A Kinney model vacuum pump. displaced 3000l/min and obtained pressure as low as 2mmHg. The pump was powered by a 3.7kw electric motor.
3) The condenser for condensing the water vapor extracted from the commodity could use either an ice condenser or a coil condenser. The ice condenser had a volume of 0.20m³ and held 125kg of crushed ice. The coil condenser had a volume of 0.22m³ and held evaporator coils refrigerated by a refrigerator with air condensing unit. The refrigerator was powered by a 10.8kw electrical motor and has 20, 000 kcal/h cooling capacity at -10°C.
4) The prototype had a pressure control magneto-valve (25mmφ) which opened or closed to atmosphere by a contact switch of marcury manometer. The pressure control magneto-valve could maintain a safe operation minium pressure to prevent products from freezing injury during vacuum cycle.
5) The prototype had a capacity to cool up to 900kg of products per hour. Its pecific capacity varied according to the size, shape, temperature, and other characteristics of the products being cooled.
6) Vacuum cooling gave fast uniform cooling to products such as lettuce, cabbage, spinach, etc, which had a large surface area when compared to their volume. The following table indicates some vacuum cooling rates of particular products cooled by the prototype portable vacuum precooler.
commodity Time Min. Initial Temp. °C Final Temp. °C
Lettuce 8 10 0
HAKUSAI 13 24 2
(chinese cabbage)
Cabbage 23 20 4
ORANDA ENDO
25 20 2
″ ″ (pre-wetting)
20 19 0
7) It seems that the larger the specific surface of product is, the longer the time required to reach a given vacuum pressure.
8) The wet bulb temperature in case of ice condenser approached closely the boiling temperatuer of water at the operation pressure (minimum pressure). But the wet bulb temperature in case of coil condenser, approached the coil condenser temperature below 0°C even at the operation pressure, 4.6-8mmHg. Therefore it was found necessary to control not only operating pressures, but condensing temperatures of coil condenser for the most efficient cooling.

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