• Korean Journal of Agricultural Science
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• v.40 no.3
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• pp.237-241
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• 2013

This study started to export an orchard tractor to Europe under the situations that R&D activities for orchard tractor were marginal and even it was not produced. The R&D for orchard tractor has been progressed and the most of it is accomplishing the goal. In this study, the durability of clutch friction part was tested for F/R clutch and moment of inertia of PTO clutch, and it was compared with the design criteria of transmission of tractor. According to the results of inertia test of F/R clutch, hydraulic pressures of clutch satisfied $1,961.33{\pm}196.13kPa$ of design criteria, and the variations of torque for forward and reverse operation were relatively constant. Therefore, it was found that the durability of clutch friction part was stable and reliable. Test results showed that the main hydraulic pressures were maintained $1,961.33{\pm}196.13kPa$ during the tests of moment of inertia of PTO clutch, and when it was operated, the hydraulic pressures were reached $1,961.33{\pm}196.13kPa$. Therefore, it was found that the hydraulic pressures of PTO satisfied the design criteria. By the results that the time of the hydraulic pressures of PTO reaching main hydraulic pressure, and that of torque values restoring to the original was same as the time of the first gear of PTO reaching the maximum rotational speed, it was found that PTO could transfer power to attachments as it was designed.

• Journal of Biosystems Engineering
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• v.6 no.2
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• pp.20-32
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• 1982

This survey was conducted to investigate the present status of farm tractor utilization for obtaining a basic reference to the establishment of the government's agricultural mechanization strategies. Thirty two counties from the eight provinces except Jeju were covered in this study. From these selected areas, 433 sample farms having farm tractor were taken to obtain the general informations by the enquete, and 93 sample farms among them to investigate the status of daily tractor use in the year of 1980. The analyzed results are summarized as follows: 1. Farm tractors owned by the rice-oriented farms holds 71.5 percent of the total number of tractors the livestock-oriented farms 17.0 percent, and the orchard-oriented farms 7.0 percent. Among the farm tractors 64.3 percent was a large size (46ps) and 35.7 percent a small size(19~23ps). 2. Most of the tractors surveyed were equipped with the essential attachments such as plow and rotavator. About 18 percent of the tractor owners had no trailer, which seemed too high considering the large percentage of tractor use for transportation. The availability of other attachments was very low except a grader on the rice-oriented farms and a hay harvester and a front loader on the livestock-oriented farms. 3. The average size of farm was 3.9 hectare for the rice-oriented farms, 13.9 hectare for the livestock-oriented farms and 7.4 hectare for the orchard-oriented farms. It was obious that the average farm size of was too small compared to the theoretical machine capacity of the tractors. 4. About 70 percent of the tractor operators were in the age of twenties and thirties. About 90 percent of them had an educational level of middle school graduate or above even though their technical level was very low. 5. Any particular problem in tractor use was not found in this survey. From the farmer's preference for purchasing a new tractor, however, it is estimated the demand on a 20-30ps tractor will be more increased. 6. The average annual use of tractor was of about 100 days or 400 hours. It appeared that the rice-oriented farms used most with 412.4 hours per year, and followed by the livestock-oriented farms with 403.6 hours, the orchard oriented farms with 377.7 hours. 7. Among the total hours of tractor use, 47.3 percent was for transportation, and 41.6 percent was for plowing and rotary tillage. The largest portion of the annual tractor use was taken by transportation on the livestock-oriented farms, by land preperation on the rice-oriented farms, and by loading and chemical spraying on the orchard-oriented farms. 8. The hours of tractor use had a peak in May. The hours of use for own farm was remarkably different among the different farm oriented, but there was no considerable difference between the too different sizes of tractor. 9. The hours of tractor use decreased as the age of the operator or the educational level increased. The reason might be that the operators who had a high educational level or were older had a tendency of disliking custom works. 10. The average custom use of tractor was 171.3 hours per year, and the ratio of custom work was 63.7 percent on the rice-oriented farms, 31.7 percent on the livestock-oriented farms and 22.4 percent on the orchard-oriented farms. Among the custom works, the most popular one was the grader leveling. 11. The charge on custom work was about 40,000 Won per hectare for plowing and rotary tillage, and it was the most expensive in the southeastern region, and next followed by the southwestern region. 12. The average plowing capacity of the small tractor was 7.8 hours per hectare in the paddy field, and that of the large tractors was 4.3 hours per hectare. The average rotary-tilling capacities of the small and the large tractors were 6.5 and 4.3 hours per hectare, in the paddy field respectively.

• Journal of Biosystems Engineering
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• v.34 no.1
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• pp.8-14
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• 2009

When a farmer buys a tractor, the power size of a tractor is determined by various factors such as farm size, farmer's age, farming type, topographical area of farm. Relationships between tractor selection and these factors were found. Three regression models were developed to analyze the relationship. Those models were an OLS-1 model (based on 567 samples having tractors), an OLS-2 model, and a Tobit model (both based on the 1,941 samples). Regression analysis results showed that farm size and farmer's age affected selection of power size for all models at an 1% significance level. It was also shown that some farming types also had significant relationships with the tractor power size. Upland cultivating farmers and livestock farmers had larger tractors than rice cultivating farmers, while orchard farmers had smaller tractors. As for the topographical area, only middle area had significant difference with plain area. Farmers who had a rice-transplanter or a combine had larger tractors than those who didn't.

• Journal of Biosystems Engineering
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• v.34 no.6
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• pp.397-403
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• 2009

This study was carried out to investigate the present status of subsoil compaction, and subsoil compaction management in orchard as a basic study for developing a self-propelled explosive subsoiler. Subsoil compaction was evaluated using the soil penetration resistance. Soil cone index was measured using the DIK 5520 type cone penetrometer in several fruit farms such as apple, pear, peach and grapes during growing seasons of these fruit in Jecheon, Gamgok, Choongju, Cheonan and Hwasung areas. Most of the subsoil managing machinery were either explosive type or digging type attached to the tractor or power tiller and turning radius of this machine was more than 3-5 m. Many of the farmers wanted to use the subsoiler which can put lime into soil and rupture soil at the same time. For most of the orchard fields, soil penetration resistance in vehicle traffic area was increased quickly and reached about 1.0 MPa in 5 cm soil depth. As the soil depth increased to 15-20 cm, cone penetration resistance reached about 2.0-2.5 MPa which restricted root growth seriously. Thus it was concluded that one of the main reason for increasing the soil compaction in orchard fields is agricultural vehicle traffic. In the vicinity of fruit trees, compaction is not so serious compared to that of the vehicle traffic area, but as the soil depth increased to 20-25 cm, in most of the orchard fields soil penetration resistance reached about 2.0-2.5 MPa which is the root growth-limiting value. Considering the rooting depth of fruit trees which ranged 30-60 cm for apple, pear and peach, and 20-30 cm for grape, it is necessary to loosen the subosoil and improve the subsoil conditions using subsoiler.

• Magazine of the Korean Society of Agricultural Engineers
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• v.13 no.3
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• pp.2349-2371
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• 1971

1. The historical development of the agriculture in Korea is observed and the future of Korean agriculture is suggested with present situation in order to recommend a direction of policy in agricultural mechanization. 2. A factor analysis of agricultural mechanization The needs of agricultural mechanization in the view of both national need and the armer's desire under the present situation are analyzed with data from the various sources. The researcher found that the agricultural mechanization is badly needed to develop prospective Korean agriculture to future. 3. The direction of agricultural mechanization. It can be said that the position of agriculture in the national economy plays a very important role. This importance should not be ignored by the Politicians in their process of developing long range economy plan. The agricultural mechanization for the modernized Korean agriculture should be directed to increase the most effective results with minimize the least sacrifice. The merry tiller is recommended to the main agricultural machinery in Korea in order to meet its small farming operation un-its(or farm size). Tractor is recommended in the plain area for the crop cultivation. The cooperative cultivation for rice and the upland crops will be developed in the plain area. Tractor, therefore, is recommended for the main agricultural machinery in these areas. Either tractor or merry tiller is recommended to the orchard area by its operating size of the orchard. The researcher also disoussed about the development of animal husbandry on the farm with increasing the farm size in order to develop meadow and pasture nuder the consideration of both the improvement of food consumption and the comprehensive development of national resources. 4. Relationship between the Performance of various agricultural machinery and the economic scale. Because of the agricultural machinery needs an expensive fixed expense(fixed cost) the total expense Per ha of the fixed expense and the operation expense should less than the traditional expense Per Dan Bo with in creased corpgiclds Per Dan Bo. Since the anual fixed expense of the agricultural machinery is figured out by the durability the more the farm size the less fixed expense of machinery is required. The formula of this principle is as follows; fixed expense for Dan Bo=Fixed expense of agricultural machinery farm size(or farming scale) The breaking-even point is the balance point between the expense of the using agricultural machinery and the traditional farming expenses. Labor cost of the Dan Bo is increasing when the management scale increases by the tradititional farming while the machanized management decrease the management cost Per Dan Bo. The reseracher found that the distribution of agricultural machinery will be the adeventeous after the year of 1981 by the result of frguring out the breaking-even point. 5. The Investigate and the conclusion. The purpose of this study is found out the direction of agricultural machanization and the breaking-even point of various agricultural machinery, there for is found out effective of the using various agricultural machinery for Collection cutter, Binder, Footing thresser, Semi-power thresser, Power thresser, Combine, Power rice-Trans-Planter, etc.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.488-499
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• 1996

A propeller type mistblower was designed and manufactured. The machine consisted of a 770 millimeters diameter propeller driven by the power take off of a tractor. It delivered 26,400 cubic meters of air per hour and has the outlet speed about 180 kilometers per hour. Spray liquid was injected at 30 bars pressure through hollow cone type nozzles which were located around the air outlet of the machine bya poston type pump. Power consumption of the machine was found to be 12.46 kilowatts and the effective forward travel speed was about 2.7 kilometers per hour. Upon spraying mango trees, it was shown that the density of spray partices was about 100 microns and consumed 3.12 liters per tree. Working speed in 6 meters row spacing mango orchard was about one hectare per hour.

• Korean Journal of Agricultural Science
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• v.43 no.3
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• pp.450-458
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• 2016

High performance small and mid-sized tractors are required for dryland and orchard operations. A power transmission system is the most important issue for the design of high performance tractors. Many operations, such as loading and lifting, use hydraulic power. In the present study, a hydraulic power transmission system for the 3-point hitch of a 50 kW narrow tractor was developed and its performance was evaluated. First, major components were designed based on target design parameters. Target operations were spraying, weeding, and transportation. Main design parameters were determined through mathematical calculation and computer simulation. The capacity of the hydraulic cylinder was calculated taking the lifting force required for the weight of the implements into consideration. Then, a prototype was fabricated. Major components were the lifting valve, hydraulic cylinder, and 3-point hitch. Finally, performance was evaluated through laboratory tests. Tests were conducted using load weights, lift arm sensor, and lift arm height from the ground. Test results showed that the lifting force was in the range of 23.5 - 29.4 kN. This force was greater than lifting forces of competing foreign tractors by 3.9 - 4.9 kN. These results satisfied the design target value of 20.6 kN, determined by survey of advanced foreign products. The prototype will be commercialized after revision based on various field tests. Improvement of reliability should be also achieved.

• The Korean Journal of Pesticide Science
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• v.11 no.4
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• pp.281-288
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• 2007

This research was carried out to propose the Korean method for estimating the agricultural occupational pesticide exposure level in orchard. The UK-POEM (UK-Predictive Operator Exposure Model) was proposed as a bench-marking model and analysed its performance properties. To extrapolate the Korean agricultural conditions, application equipment, application method, work rate per day, application volume and spraying time of pesticide was surveyed for Korean 204 orchard farmhouse. This survey indicate that the major application equipments are speed sprayer(64.9%) and motor sprayer(33.9%). When they spayed the pesticide with a speed sprayer, they worked for more than 4 hours on area of 4 ha per day. In case of using motor sprayer, they worked for more than 4 hours on area of 1 ha. Based on the above survey result, Korean method for estimating the pesticide exposure level of agricultural worker was proposed finally.