• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.341-348
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• 2013

Maintenance of adequate soil tension or content during the period of crop growth is necessary to support optimum plant growth and yields. A better understanding of soil tension and content for precision irrigation would allow optimal soil water condition to crops and minimize the adverse effects of water stress on crop growth and development. This research reports on a comparison of soil water tension and content variations in differently textured soils over time under drip irrigation using two different water management methods, i.e. pulse time and required water irrigation methods. The pulse time-based irrigation was performed by turning the solenoid valve on and off for preset times to allow the wetting front to disperse in root zone before additional water was applied. The required water estimation method was a new water control logic designed by Rural Development Administration that applies the amount of water required based on a conversion of the measured water tension into water content. The use of the pulse time irrigation method under drip irrigation at a high tension of -20 kPa and high temperatures over $30^{\circ}C$ was not successful at maintaining moisture tensions within an appropriate range of 5 kPa because the preset irrigation times used for water control could not compensate for the change in evapotranspiration during day and night. The response time and pattern of water contents for all of the tested soils measured with capacitance-based sensor probes were faster and more direct than those of water tensions measured with porous and ceramic cup-based tensiometers when water was applied, indicating water content would be a better control variable for automatic irrigation. The required water estimation-based irrigation method provided relatively stable control of moisture tension, even though somewhat lower tension values were obtained as compared to the target tension of -20 kPa, indicating that growers could expect to be effective in controlling low tensions ranging from -10 to -20 kPa with the required water estimation system.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.336-336
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• 2022

빗물자원의 대부분은 바다로 유입되어 소모되거나, 하수로 유입되어 불필요한 고도처리 공정이 진행되고, 하수처리장 용량에 과부하를 발생시키는 등 막대한 예산이 투입되고 있는 실정이다. 갈수기시 농가에서 용수를 확보하기 위한 용수 운반장치 등 기반구축이 쉽지 않으며, 인력 부족으로 정상적인 용수공급에 어려움을 겪고 있다. 이에 빗물자원을 용수로서 효율적으로 활용하기 위한 시스템의 구축이 필요하다. 본 연구는 빗물저류조에 스마트 관수제어 시스템을 적용한 것으로 지중에 설치된 토양수분 센서와 저류조 내부의 수위 센서에서 관측된 데이터를 토대로 자동으로 지중에 수분을 공급하는 시설이다. 지중에 수분이 부족할 경우 밸브를 열어 자동으로 펌프를 가동시켜 저류조 내부의 물을 지중으로 공급시키며 지중의 수분이 충분하거나 저류조 내부의 물이 부족해질 경우 밸브를 닫아 공급을 중단하도록 한다. 또한 저류조의 수위와 토양의 수분량, 펌프의 작동여부 등은 앱을 이용하여 실시간으로 확인이 가능하며, 스마트폰 앱을 이용한 수동조작 또한 가능하다. 본 기술은 집수, 저류, 공급, 통신, 제어, 센서 총 6종의 모듈로 구성되어 있으며, 사용자의 환경 및 예산의 따라 집수, 저류, 공급 모듈 등 맞춤형 제품 구성이 가능하도록 개발하였다. 저류조의 물공급을 관리, 제어하는 시스템으로 센서로부터 전송받은 데이터를 기준으로 펌프를 작동시켜 수분공급을 제어할 수 있으며 해당 기록을 서버에 저장하여 데이터의 통계를 구할 수 있도록 하였다. 사용자가 앱을 통하여 직접적인 제어 및 가동환경에 대한 설정을 할 수 있어 사용자가 직접 현장에 오지 않아도 토지의 현황과 저류조의 수위, 수분 공급상황 등을 직접 제어할 수 있도록 개발하였다.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2000.10b
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• pp.120-123
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• 2000

느타리버섯의 재배 환경관리는 버섯의 품질과 수확량을 좌우하는 매우 중요한 요소이지만 버섯배지의 적정 수분유지 및 습도조절에는 많은 노력과 시간이 요구된다. 이 연구는 느타리버섯의 수확시기에 버섯재배사 통로를 왕복 주행하며 버섯균상 2열 4-5단 균상에 필요한 량의 물을 뿌려주고 바람으로 배지표면의 물을 말려주며 주기적으로 안개분무로 가습하여 버섯 재배환경을 적합하게 유지하는 장치개발을 위하여 수행하였다. (중략)

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.02a
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• pp.48-53
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• 2002

가. 작업단계 별 작업수단 및 노동투하시간 -고추재배는 포장준비 등 일부작업을 제외하고는 인력작업에 의존하고 있으며, 육묘에서 수확 및 수확후 포장처리가지의 총 노동투하시간은 266.7시간/10a로 수확작업이 44.5%로 많았으며, 다음으로 육묘, 지주세우기 및 제거, 정식, 방제 순으로 나타났다. 따라서 노력 및 생산비절감을 위해서는 고추재배 기계화가 시급한 것으로 판단된다. 나 일관기계화방안 -고추재배시 기계화를 저해하는 요인으로는 경지규모의 협소함, 재배지의 필지의 분산, 협소한 조간간격, 비닐멀칭 및 지주유인재배, 수확기간의 길이가 길고 횟수가 많음 등으로 나타났으며, 기계화가 곤란한 것으로 나타났으며, 고추재배일관기계화를 위하여는 공동 또는 공정육묘, 트랙터 등 대형기계중심의 포장준비, 정식은 자동정식기보급, 관수·시비자동화와 붐방제기 또는 방제장치시설화, 기계수확이 되어야할 것으로 판단되었다.

• Journal of Bio-Environment Control
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• v.6 no.4
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• pp.242-249
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• 1997

Environmental control operations have been considerably contributed to the reduction of labor cost in both plastic film and glass greenhouses since government supported projects were begun. However, some problems are still remaining on the optimal environmental control and excessive operation due to an inflexible software regulating ventilation gear - reducers. The unadjustable software caused the damage of ventilation system, resulting in heat stresses of crops. This study was performed to develop a ventilation software controlling the vent opening level, opening sequence, based on the wind direction, and control interval according to the difference between ambient and set- up temperatures. The software included a beeper system alarming urgent cases, while a manager was remote from the greenhouse. A compatible hardware with the software was also developed by using a low-cost diffused DSP controller.

• Journal of Bio-Environment Control
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• v.24 no.3
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• pp.153-160
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• 2015

The objectives of this study were to determine optimal length of off-time between irrigation cycles to improve irrigation efficiency using a frequency domain reflectometry (FDR) sensor-automated irrigation (FAI) system for tomato (Solanum lycopersicum L.) cultivation aimed at minimizing effluent from coir substrate hydroponics. For treatments, the 5-minute off-time length between 3-minute run-times (defined as 3R5F), 10-minute off-time length between 3-minute run-times (defined as 3R10F), or 15-minute off-time length between 5-minute run-times (defined as 5R15F) were set. During the 3-minute or 5-minute run-time, a 60mL or 80mL of nutrient solution was irrigated to each plant, respectively. Until 62 days after transplant (DAT) during the autumn to winter cultivation, daily irrigation volume was in the order of 3R5F (858mL) > 5R15F (409mL) > 3R10F (306mL) treatment, and daily drainage ratio was in the order of 3R5F (44%) > 5R15F (23%) > 3R10F (14%). Between 63 and 102 DAT, daily irrigated volume was in the order of 5R15F (888mL) > 3R5F (695mL) > 3R10F (524mL) with the highest drainage ratio, 19% (${\pm}2.6$), at the 5R15F treatment. During the spring to summer cultivation, daily irrigation volume and drainage ratio per plant was higher in the 3R5F treatment than that of the 3R10F treatment. For both cultivations, a higher water use efficiency (WUE) was observed under the 3R10F treatment. Integrated all the data suggest that the optimal off-time length is 10 minutes.

• Journal of Bio-Environment Control
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• v.6 no.4
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• pp.258-263
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• 1997

The result was summarized of basic test and field test to find what quantity of irrigation, what state of compaction and what size of transplanting hopper could induce the optimum taking root in the transplantation of plug seedling by transplanters, and thus acquired the basic data for the development of the related transplanters and the optimum growth and development control. Livability of vegetables after transplanting had no significant difference with respect to for the size of hopper, but was greatly affected by the length of seedlings. The longest possible length of seedling for transplanting and optimal length were found to be 30cm and 28cm, respectively. For irrigation when transplanting red pepper or Chinese cabbage it was thought that large-sized hopper was appropriate. The livability of plug seedling 10 days after transplantation was mainly affected by soil moisture content. Consequently it was thought no irrigation would be needed when transplanting at the soil moisture content of more than 18% ; irrigation of more than 50cc would be needed at the soil moisture content of 13% : initial irrigation of more than 100cc and subsequent irrigation would be needed at the soil moisture content of less than 3.8%. The improvement of soil compaction method (left and right side compaction) with conventional semi-automatic transplanter was not necessary, since there was no difference in livability depending on the compaction methods, left-right side compaction or back-forth-left-right side compaction.

• Journal of Bio-Environment Control
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• v.6 no.3
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• pp.159-167
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• 1997

To cope with the mass-production and supply of plug seedling, the supply of transplanters is necessary. In the study, a transplanting test was carried out to find the optimum working condition in the mechanizd transplantation and to acquire the basic data for the improvement of transplanters by the research and analysis of working capacity of the local manual transplanters. The size of hopper affected transplanting stand and rate. Re-irrigation was required for the transplanted seedlings because they wilt 1 day after the transplanting if soil compaction is incomplete. Consequently, back-forth-left-right compaction method was good for soil covering and compaction. It may be thought to increase the amount of irrigation water at the time of transplanting by double-irrigation mechanism, but it needs to increase the larger water tank which makes the operation uneasy. So, assuming the working model by 1 or 2 operators with the machine size as small as possible, it seemed that eliminating of automatic irrigation method was desirable in view of efficiency. Though semiautomatic transplanter needs some structural improvements, it seemed still suitable for transplanting of plug seedlings such as 45-day red pepper seedlings in 128-hole tray and 25-day Chinese cabbage seedling in 128-hole tray. If traveling speed of the transplanter is limited to less than 14 m/min, with the transplanting depth of 2~3cm and transplanting space of 30cm.

• Korean Journal of Agricultural Science
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• v.36 no.1
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• pp.73-85
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• 2009

An investigation was conducted to get the basic data for establishing structural safety and environmental management of tomato greenhouses in Chungnam region. The contents of the investigation consisted of actual state of greenhouse structures and environmental control facilities. Most of greenhouses were arch type single-span plastic houses and they had too low height for growing tomatoes. Frameworks of multi-span greenhouses were suitable, but those of single-span were mostly insufficient. Every greenhouse had thermal curtain movable or covering fixed inside the greenhouse for energy saving, and heating facilities were mostly warm air heater. Irrigation facilities were mostly drip tube and controlled by manual operation or timer. Almost all of the greenhouses didn't install high level of environmental control facilities such as ventilator, air circulation fan, $CO_2$ fertilizer, insect screen, supplemental light, and cooling device.

• Journal of Bio-Environment Control
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• v.8 no.4
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• pp.257-264
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• 1999

The trickling system for automatic and individual watering were made with Bunchungto, Ongito and Backjato. The thickness of ceramics were 1.0, 1.5, 2.0, 2.5 and 3.0mm. And they were fired in a muffle furnace at five different temperatures between 500 and 900'E during 12 hours. The upper plastic parts of sensor consisted of five elements made by steel mold. With the photo fiber sensor attached to datalogger, an accumulated amount of drops for every 10 minutes were recorded. The porosity is higher in the order of Bunchungto, Backjato and Ongito; also, as the firing temperature is higher and the thickness is thicker, the porosity is higher. The ceramic sensors consisted of $SiO_2$ of 54.17~71.62wt.%, A1$_2$ $O_3$ of 15.42~33.79wt.% and the rest of 10wt.%, those were Fe$_2$ $O_3$, CaO, MgO, Na$_2$O, $K_2$O, Ti $O_2$, P$_2$ $O_{5}$. The pattern of dropping were changed according to the variety, thickness and firing temperature of ceramics. As the ceramics were made thicker, the fluctuation of dropping became more rapid, but it did not regularly work at 1mm thickness. As the firing temperature of ceramics became higher, the fluctuation of dropped amount became more rapid.