• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1997.05a
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• pp.87-91
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• 1997

시설원예의 현대화에 따른 각종 피복자재의 도입ㆍ개발과 시설재배 면적의 급속한 증가로 인해 그에 따른 피복자재의 광환경 특성이 검토되지 않고 피복자재가 이용되고 있다. 따라서 본 연구는 연질필름중 가장 피복재배면적이 많은 PE(Polyethylene)필름과 경질판PC (Polycarbonate), PET (Poyethylene terephthalate), 유리 피복자재의 광환경 개선을 위한 기초 연구로 실시하였다. 1. 피복자재별 광투과율은 PE가 약 80%, 유리가 약 90%로, 유리 온실은 완공후 4년이하 경과했음에도 약 5개월 된 PE 보다 광투과율이 높았다. 2. 피복자재별 광반사율은 PE가 가장 높은 약 3% 였고 PC>PET>유리의 순으로 나타났다. 3. 피복자재별 광흡수율은 PE는 전파장에 걸쳐 고루 흡수되었으나 PC, PET는 자외선의 흡수가 많았다. 4. 피복자재별 토마토 군락내 광분포에서 제 1과방의 광량은 시설내 투과일사의 약 15%정도였다. 5. 피복자재별 토마토엽의 증산속도는 PE가 다소 낮았으나 처리간 큰 차이는 없었다. 6. 수경재배의 토마토의 광합성속도가 토경재배 보다 낮았다.

• Journal of Bio-Environment Control
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• v.22 no.3
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• pp.234-240
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• 2013

The purpose of this study was to provide basic data used in greenhouse design, and for this purpose, the crop loads of tomato and paprika which have high crop load among crops cultivated in greenhouse were measured. The maximum differences in lowest and mean temperatures between cultivation year and normal years for winter season were -5.6 and $-4.9^{\circ}C$, respectively and those for summer season were 3.0 and $1.5^{\circ}C$, respectively. The calibration of push & pull gauge indicated approximate 0.99 of coefficient of determination, representing very high association. The planting densities of paprika and tomato were 3.43, 3.56 and $2.13plants{\cdot}m^{-2}$, respectively. The yields were 4.1, 4.3 and $16.2kg{\cdot}plant^{-1}$, corresponding to 14.1, 15.2 and $34.5kg{\cdot}m^{-2}$ of yield per unit area. The maximum loads were 1.3, 1.5 and $3.3kg{\cdot}plant^{-1}$, respectively. When the paprika were hanged on cross beam, the total crop load applied to it was estimated to be $15.3{\sim}15.9kg{\cdot}m^{-2}$, and when the weights of gutters supporting the cultivation beds, the total weights were $26.0{\sim}26.9kg{\cdot}m^{-2}$.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.143-143
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• 2017

산업이 고도화됨에 따라 자동화 기계 및 로봇에 의해 대량 생산 되는 품목과 달리, 작업 절차의 비정형성, 비연속성 등으로 인해 여전히 농업에 많은 인력이 투입되고 있다. 국제노동기구에 따르면, 세계 인력의 절반이 농업 인력에 해당하고 작업 중 부상이나 사망 등으로 인해 가장 위험한 직업군 중 하나에 해당하는 것으로 나타났다. 시설 재배 농업의 경우, 노동집약적인 온실 내 작업 특성상 잘못된 자세로 작업하거나 지나친 작업량 등으로 인해 작업자에게 근골격계 질환이 발생할 수 있다. 근골격계 질환으로 인해 작업효율이 감소하거나 생산비용의 증가로 이어질 수 있으며, 농가 수익에 손실이 발생할 수 있다. 이에 본 연구에서는 현행 시설 재배 농업에서 사용되는 레일 전동 작업차를 이용하여 작업자가 토마토를 수확할 때의 신체에 대한 농작업의 부하를 평가하고자 하였다. 작업차를 이용한 주요 작업 절차는 작물로부터 과실 수확, 과실 상자에 과실 투입, 빈 과실 상자와 가득 찬 과실 상자의 교대, 작업차 위의 과실 상자를 운반용 파레트에 하역하는 순서로 이루어지는 것을 확인하였다. 비디오장비로 촬영된 일련의 농작업 과정을 OWAS, RULA, REBA와 같은 체크리스트형 인간공학적 작업 부하 평가 도구를 이용하여 평가한 결과, 기존 레일 전동 작업차를 이용한 농작업의 근골격계 질환 유발 가능성을 확인하였다. 동작별 위험성을 토대로 근골격계 질환 유발 가능성이 높아 개선이 필요한 농작업 동작을 선정하였다. 선정된 동작은 실험실 내 환경에서 피실험자를 통한 모의 동작의 생체 신호 계측을 통해 신체 부하 정도를 정량적으로 측정할 수 있으며, 보조가 필요한 신체 부위를 특정하거나 안전성 확보가 필요한 동작에 대한 증거가 될 수 있다. 본 연구를 통해 향후 토마토 온실 내 신선도 유지를 위한 레일 전동 작업차의 개발에 작업자의 안전과 효율성 향상을 위한 인간공학적 설계를 적용할 수 있을 것으로 기대한다.

• Journal of Bio-Environment Control
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• v.6 no.3
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• pp.205-215
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• 1997

An accurate transpiration model for greenhouse tomato crop, which is liable to transpiration depression and yield loss because of low solar radiation and high humidity, could be an efficient tool for the optimum control of greenhouse climate and for the optimization of Irrigation scheduling. The purpose of this study was to develop transpiration model of greenhouse tomato and to carry out the experimental verification. The formulas to calculate the canopy transpiration and temperature simultaneously were derived from the energy balance of canopy. Transpiration and microclimate variables such as net radiation, solar radiation, humidity, canopy and air temperature, etc. were simultaneously measured to estimate parameters of model equations and to verify the suggested model. Leaf boundary layer resistance was calculated as a function of Nusselt number and stomatal diffusive resistance was parameterized by solar radiation and leaf-air vapor pressure deficit. The equation for stomatal diffusive resistance could explain more than 80％ of its variation and the calculated stomatal diffusive resistance showed good agreements with the measured values in situations independent of which the constants of the equation were estimated. The canopy net radiation calculated by Stanghellini's model with slight modification agreed well with the measured values. The present transpiration model, into which afore-mentioned component equations were assembled, was found to predict the canopy temperature, instantaneous and daily transpiration with considerable accuracy in greenhouse climates.

• Korean journal of applied entomology
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• v.59 no.1
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• pp.55-64
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• 2020

Smart greenhouses are primarily used for growing fruits and vegetables, such as sweet peppers, tomatoes, strawberries. Although the number of smart greenhouses has been increasing exponentially, no studies have been performed to evaluate the state of smart greenhouses in Korea. Therefore, this study was conducted to determine current state of smart greenhouses with regard to greenhouse specifications, crop growing methods, pests, and user satisfaction in Korea. Contact information for smart greenhouses was provided by the officials of local agricultural research and extension services. This survey was conducted by visiting each greenhouse. Results showed that approximately 50% of surveyed smart greenhouses were between 3,300 ㎡ and 6,600 ㎡. The most frequently chosen method for pest control was chemical pesticides (97.1%). Powdery mildew and gray mold comprised 54.4% and 33.8% of the crop diseases, respectively. All tomato greenhouse farmers considered whiteflies the most problematic pest. In contrast, 76.5% and 70.6% of sweet pepper farmers believed thrips and aphids posed significant threats, respectively. The mean satisfaction score was 7.5 out of 10 points, with 10 being "extremely satisfied". These results will aid in decision making with respect to the management of current smart greenhouses and the design of future smart farms in Korea.

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.428-436
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• 2012

This study aimed to develop the multi-span plastic greenhouse which is suitable for tomato cultivation and is safe against climatic disasters such as typhoon or heavy snow. The width and heights of eaves and ridge of newly developed tomato greenhouse are 7, 4.5 and 6.5 m, respectively. The width is the same but the eaves and ridge heights are 1.8 and 2 m higher than conventional 1-2 W greenhouses, respectively. Cross beam has been designed as a truss structure so it can sustain loads of tomato and equipment. Tomato greenhouse has been designed according to climatic disaster preventing design standard maintaining the high height. In other words, the material dimensions and interval of materials including column and rafter have been set to stand against $40m{\cdot}s^{-1}$ of wind and 40 cm of snow. Tomato greenhouse has been equipped with rack-pinion type roof vents which have been used in glass greenhouse in order to prevent excessive rise in air temperature. This vent type is different from that of 1-2 W type greenhouse which is made by rolling up and down the vinyl at upper part of column. Roof vents are installed at ridge, and thus external air inflow and natural ventilation are maximized. As the height increases, heating cost increase as well and, therefore, tomato greenhouse has been equipped with multi-layered thermal curtain, of which thermo-keeping is excellent, to prevent heat from escaping.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.4
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• pp.259-264
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• 1993

Allelopathic chemicals exudated from plants stimulate or inhibit crops directly or indirectly. To prove the effects of allelochemics, we isolated and identified the compounds by bioassays on the monoculture and crosscropping cultre systems. p-Coumaric acid were exudated on all of the test crops such as tomato, red pepper, lettuce, chinese cabbage and sesame, but pyrogallol and phenylacetic acid on tomato. hydroquinone on red pepper and egg plant, pyrogallol on lettuce, and vanillic acid on chinese cabbage. The highest total concentration of allelochemics was $5,883{\mu}g$ on tomato, lowest was $220{\mu}g/g$ dry plant weight on sesame. On the cross-cropping culture of tomato-egg plant, tomato-red pepper, chinese cabbage-egg plant, chinese cabbage-red pepper and chinese cabbage-sasame, the plant height, aerial dry weight and total dry weight of the tomato and the chinese cabbage were inereased contrast with monoculture, but decreased greatly on red pepper and sesame. Growth rate of both crops on the cross-cropping culture of tomato-chinese cabbage declined, while that of chinese cabbage was increased but lettuce decreased on the chinese cabbage-lettuce cross-cropping culture contrast with monoculture.

• Journal of Bio-Environment Control
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• v.20 no.1
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• pp.1-7
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• 2011

The objective of the present study is to identify the applicability of a low pressure fogging system for cooling commercial tomato greenhouse. In particular, the cooling system in this experiment utilizes low pressure spray nozzles which were developed in Korea recently. The experimental result that the temperature in fog-cooled greenhouse was lower than the non-cooled greenhouse showed the cooling effect by the low pressure fogging system. But because the relative humidity in fog-cooled greenhouse was comparatively low, the satisfactory cooling effect could be acquired by narrowing the space of fog nozzles and extending fogging time to supply more fog spray quantity. The variation of temperature distribution in fog-cooled greenhouse along timelag was insignificant during short time, but that was great during long period of day. This result showed the variation of temperature along timelag was slight by fog cooling but great by other factors like radiation, ventilation, air flow, etc. The advanced operation technology of fog system was required to reduce the variation of temperature along time lag. We plan to suggest the advanced installation and operation technology of low pressure fogging system for cooling commercial tomato greenhouse by further experiments in near future.

• The Korean Journal of Mycology
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• v.48 no.4
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• pp.369-379
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• 2020

Black mold was frequently observed on tomatoes grown in a greenhouse in Suwon, Korea in July 2018. The incidence of the disease was 5.0-25.0% (average 12.3%) and 2.0-7.0% (average 3.7%) in the context of tomato and cherry tomato fruits, respectively. Sixteen single-spore isolates of Alternaria sp. were obtained from the diseased fruits and investigated for their morphological characteristics. Among the isolates, eight were used for sequencing analysis. All of the isolates were identified as Alternaria alternata based on their morphological and molecular characteristics. The pathogenicity of four isolates of A. alternata was investigated using three varieties each of tomato and cherry tomato via artificial inoculation. All of the isolates induced black mold symptoms on the inoculated tomato fruits. Notably, the symptoms were similar to those observed in the greenhouse. However, the pathogenicity tests revealed that different tomato varieties presented distinct patterns of susceptibility to the isolates. This is the first report of A. alternata causing black mold on tomato fruits in Korea.

• Horticultural Science & Technology
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• v.29 no.5
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• pp.420-432
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• 2011

Population dynamics of greenhouse whitefly, Trialeurodes vaporariorum (Westwood), were modeled and simulated to compare the temperature effects of air and tomato leaf inside greenhouse using DYMEX model simulator (pre-programed module based simulation program developed by CSIRO, Australia). The DYMEX model simulator consisted of temperature dependent development and oviposition modules. The normalized cumulative frequency distributions of the developmental period for immature and oviposition frequency rate and survival rate for adult of greenhouse whitefly were fitted to two-parameter Weibull function. Leaf temperature on reversed side of cherry tomato leafs (Lycopersicon esculentum cv. Koko) was monitored according to three tomato plant positions (top, > 1.6 m above the ground level; middle, 0.9 - 1.2 m; bottom, 0.3 - 0.5 m) using an infrared temperature gun. Air temperature was monitored at same three positions using a Hobo self-contained temperature logger. The leaf temperatures from three plant positions were described as a function of the air temperatures with 3-parameter exponential and sigmoidal models. Data sets of observed air temperature and predicted leaf temperatures were prepared, and incorporated into the DYMEX simulator to compare the effects of air and leaf temperature on population dynamics of greenhouse whitefly. The number of greenhouse whitefly immatures was counted by visual inspection in three tomato plant positions to verify the performance of DYMEX simulation in cherry tomato greenhouse where air and leaf temperatures were monitored. The egg stage of greenhouse whitefly was not counted due to its small size. A significant positive correlation between the observed and the predicted numbers of immature and adults were found when the leaf temperatures were incorporated into DYMEX simulation, but no significant correlation was observed with the air temperatures. This study demonstrated that the population dynamics of greenhouse whitefly was affected greatly by the leaf temperatures, rather than air temperatures, and thus the leaf surface temperature should be considered for management of greenhouse whitefly in cherry tomato grown in greenhouses.