• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.1021-1030
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• 1996

The mechanism of the mulch film cutter assembly designed as an integral part of a rice transplanting device was developed for mulching cultivation of early season culture rice. This mulch film cutter assembly was directly attached to the transplanting device of the rotary type Japanese transplanter. The principle is that the knife cut a planting slit on the polyethylene film while the planting finger immediately plants seedling into the soil through the planting slit. Computer results implied that the knife of the mulch film cutter assembly can make appropriate planting slit on the polyethylene film as the planting finger effectively plants the seedlings into the paddy soil through the same planting slits.

• Journal of the Korean Society of International Agriculture
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• v.30 no.4
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• pp.292-299
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• 2018

In a survey in which farmers were asked about their levels of satisfaction with agricultural machines, Japanese products scored higher than local products by 1.2, 1.3, and 1.4 times for tractors, combine harvesters, and rice transplanter, respectively. Japanese products corresponded to generally high satisfaction levels in terms of operating performance, operability, frequency of breakdowns, and durability, excluding sales price and after-sales services. Effective countermeasures through quality improvement are therefore necessary for Korean products. Furthermore, a survey of dealers showed that the components and consumables for core agricultural machines had high frequencies of breakdowns and repairs. Four major components of tractors represented 85.3% of all breakdowns and repairs, five components of combine harvesters represented 89.6%, and three components of rice transplanters represented 80.5%. Moreover, a comparison of the technological levels between local and imported machines showed that the local machines' levels were at 60-100% for tractors, 70-100% for combine harvesters, and 70-95% for rice transplanters. Small and mid-sized tractors, 4 interrow combine harvesters, and 6 interrow rice transplanters showed similar levels of technology. The results of the analysis suggest that action is urgently needed at a policy level to establish an agricultural machinery component research center for the development, production, and supply of commonly-used components, with the participation of manufacturers of agricultural machines and components, in order to enhance the competitiveness of local manufacturers and to revitalize the agricultural machine market.

• Journal of Biosystems Engineering
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• v.41 no.4
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• pp.294-303
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• 2016

Purpose: This study aimed to evaluate the profitability of four selective mechanization systems in rice cultivation. Methods: Field experiments were conducted in the farmers' field during the wet season (June to November) of 2015 in Bangladesh. Mechanization systems were applied to evaluate four different selective levels (treatment) in eleven consequent operations. Seedlings were raised in a traditional seedbed and trays for manual and mechanical transplanting, respectively. Land preparation, irrigation, fertilizer, pesticide, carrying, and threshing and cleaning operations were performed using the same method in all the experimental plots. The mechanical options in the transplanting, weeding, and harvesting operations were changed. The mechanization systems were $S_1$ = hand transplanting + hand weeding + harvesting by sickle, $S_2$ = mechanical transplanting + Bangladesh Rice Research Institute (BRRI) weeder + reaper, $S_3$ = mechanical transplanting + BRRI power weeder + reaper, and $S_4$ = mechanical transplanting + herbicide + reaper. This experiment was performed in a randomized complete block design with four replications. Power tiller, rice transplanter, BRRI weeder, BRRI power weeder, self-propelled reaper, BRRI open drum thresher, and BRRI winnower were used in the respective operations. Accordingly, the techno-economic performances of the different technologies were calculated and compared with those of the traditional system. Results: The mechanically transplanted plot produced 6-10% more yield than the hand transplanted plot because of the use of tender-aged seedlings. Mechanical transplanting reduced 61% labor and 18% cost compared to manual transplanting. The BRRI weeder, BRRI power weeder, and herbicide application reduced 74, 91, and 98% labor, respectively. The latter also saved 72, 63, and 82% cost, respectively, compared to hand weeding. Herbicide application reduced the substantial amount of labor and cost in the weeding operation. Mechanical harvesting also saved 96% labor and 72% cost compared to the traditional method of harvesting using sickle. Selective mechanization saved 15-17% input cost compared to the traditional method of rice cultivation. Conclusions: Mechanical transplanting with the safe use of herbicide and harvesting by reaper is the most cost- and labor-saving operation. The method might be the recommended set of selective mechanization for enhancing productivity.

• Journal of Biosystems Engineering
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• v.15 no.2
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• pp.88-98
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• 1990

The purpose of this study was twofold : first, to reduce as much as possible the shaking moments of the crank-type transplanting mechanism of walking-type rice transplanters, and second, to evaluate whether or not a crank-type transplanting mechanism, if its shaking moment is reduced, can be used in riding-type transplanters for high speed transplanting operations. For these purposes, kinematic and force analyses of the currently available crank-type transplanting mechanisms were made and their results were compared with those observed by experimentation. The degree of shaking moment effect was also estimated Various efforts to minimize the shaking moments led to the development of a crank-type mechanism with a balancing gear, in which an eccentric balancing gear is combined into the driven link axis. Analysis of the developed mechanism showed that about 20% of the shaking energy can be reduced and about 40% of reduction in peak shaking moment can be obtained when comparing with those obtained without the balancing gear. It was concluded that crank-type transplanting mechanisms can be used for high speed operations with a forward speed of 0.9-1.2m/s if the balancing gear is additionally mounted. However, further considerations must be made to solve the space constraints in relation to the structural frame of riding type of rice transplanters.

• Journal of Biosystems Engineering
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• v.27 no.2
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• pp.79-88
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• 2002

This study was conducted to develop system for high speed rice transplanting machines. The control system includes a sensor detecting the tilt angle of the seedling bed, a micro-controller and a hydraulic system consisting of a double acting cylinder, a four-way three-position solenoid valve, a relief valve and a hydraulic pump. The levelling system shared the pump with the existing steering control, resulting in a tandem center circuit for the steering and levelling control systems. Using the input signal from the sensor, the micro-controller determined and generated the output signal to control the cylinder through the solenoid valve to keep the seedling bed always parallel to the water surface regardless of soil unevenness during the transplanting operations. Both an ON/OFF and a PWM control schemes were tested. When the flow rate was more than 1 ι/min in the ON/OFF control, the system showed unstable rolling. However, in the PWM control, the system worked stably although the flow rate was more than 1 ι/min. The PWM control showed a better performance when a large difference between the angle and the dead band of the control system occurred. The characteristics of tile system response to given tilt angles were predicted by a computer simulation. Both the ON/OFF and the PWM control systems worked well providing that the operating and waiting times were properly adjusted.

• Korean Journal of Agricultural Science
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• v.5 no.2
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• pp.49-55
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• 1978

In order to get healthy seedling of rice suitable for rice transplanter, the growing characteristics of the seedling grown under different growing days and sowing densities were invesigated and the results obtained were summarized as follows; In the 20 days old seedling, the difference of growing state of seed ling and its characteristics between the two types of nursery bed was not found, but for the 30 days old seedling, both of the crop growth rate and the relative growth rate on the band-type nursery bed appeared higher than those on the mat-type nursery bed. And also, "the dry weight, the content of cardohydrate and the ratio of dry weight to plant height of the seedling grown on the band-type nursery bed were much higher than those on the mat-type nursery bed, however the amount of difference of seedling characteristics between two types of nursery bed was decreased for 40 days old seedling and leaf number was not increased. The amount of the seedling growth was increased with less density of sowing and for the difference between the higher and the less density, the difference getting bigger with the longer nursery days. The maximum density of sowing was approximately 200cc per nursery case on the band-type nursery bed and 250cc per nursery case on the mat-type nursery bed. It was seemed that the growing uniformity of the seedling grown on the mat-type nursery bed was better than that on the band- type nursery bed, As the coefficient of variation of the plant height and the leaf numbers of the seedling grown on the band- type nursery bed was higher than that on the mat-type nursery bed.

• Journal of Biosystems Engineering
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• v.29 no.5 s.106
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• pp.441-450
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• 2004

This study was performed to estimate mid and long term demands of a tractor, a rice transplanter, a combine and a grain dryer by using logistic curve function and Markov chain model. Field survey was done to decide some parameters far logistic curve function and Markov chain model. Ceiling values of tractor and combine fer logistic curve function analysis were 209,280 and 85,607 respectively. Based on logistic curve function analysis, total number of tractors increased slightly during the period analysed. New demand for combine was found to be zero. Markov chain analysis was carried out with 2 scenarios. With the scenario 1(rice price $10\%$ down and current supporting policy by government), new demand for tractor was decreased gradually up to 700 unit in the year 2012. For combine, new demand was zero. Regardless of scenarios, the replacement demand was increased slightly after 2003. After then, the replacement demand is decreased after the certain time. Two analysis of logistic owe function and Markov chain model showed the similar trend in increase and decrease for total number of tractors and combines. However, the difference in numbers of tractors and combines between the results from 2 analysis got bigger as the time passed.

• Journal of Biosystems Engineering
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• v.2 no.2
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• pp.15-36
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• 1977

일반적으로 기계의 분석법은 도해적 방법으로 대별할 수 있다. 도해적 방법이 간편하지만 그 정학성이 부정하고 해석적 방법은 복잡한 계산과정을 요구한다. 최근 많은 컴퓨터 시설은 해석적 방법의 활용을 가능케 하였으나 간단한 기구의 분석은 EH한 경제적인 면에서 컴퓨터의 광범위한 사용을 어렵게 하고 있다. 본 연구는 소형 계산기를 이용하여 크랭크로커 기구를 분석할 수 있는 분석적 방법을 위한 방정식을 유도하고 이 방법을 동력 이앙기의 직촌기구의 분석에 적용하였다. 기구 표시법으로 크랭크-로커 기구를 심볼 방정식으로 나타내고, 기구상의 각 링크에 고정된 좌표계를 3$\times$3행렬식을 이용하여 좌표계를 전이 시키는 방법으로 방정식들을 유도하였다. 크랭크-로커 기구의 링크상의 어떤 한점의 위치벡타를 행렬 방정식으로 표시하고 이 행렬 방정식을 일차, 이차 미분하여 그 점에 대한 속도와 가속도 방정식은 유도하였다.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.07a
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• pp.3-8
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• 2002

쌀은 전 세계에서 매년 약 4억 톤이 생산되어 세계인구의 약 45%에게 주식으로 제공되고 있다. 우리나라에서는 쌀 농사가 농업소득의 약 44%를 차지하는 농가의 주 소득원으로 경제적 비중이 크다. 또한 WTO 개방경제 체제에서는 쌀 생산농가가 생존하기 위해서는 생산비 절감을 통한 가격경쟁력 제고와 품질향상을 통한 소비자 선호도 확보가 가장 중요한 과제이다. 지금까지 우리나라의 벼농사는 생산비 절감이나 품질향상보다는 수량증대에 치중하여 쌀 산업의 국제경쟁력은 매우 취약한 실정이다. 손 모내기에서 중묘 기계이앙 기계기술이 확립되어 확대보급 되었고 이보다 육묘비용 및 노력을 절감할 수 있는 어린 모 재배 기술이 보급되기 시작하였으나, 미국 등 선진국의 벼농사 노동 투하시간 3.5시간/㏊에 비하여 우리나라는 328시간/㏊ 쌀 생산비는 미국의 2,018천원/㏊에 비하여 우리나라는 5,105/천원㏊로 월등히 높아 노동 투하시간을 획기적으로 줄일 수 있는 기계기술 개발이 요구되고 있다. (중략)

• Journal of Biosystems Engineering
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• v.22 no.2
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• pp.127-136
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• 1997

This study was accomplished to develop a pneumatic granular applicator that can be attached to the conventional ride-on rice transplanter. Operating conditions of a metering device for the applicator were determined so as to obtain the required discharge rate of granules for field application. The shape and size of diffuser was selected for the applicator and the spacing between diffusers on a boom and the boom height were determined as an optimal application condition for uniform distribution. The diffuser spacing of 1m for the fertilizer and the diffuser spacing of 0.8m for the pesticide at the boom height over 0.8m were acceptable.