• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1993.10a
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• pp.15-16
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• 1993

자연광 이용 식물공장의 주년 이용을 위해서는 하기주간의 냉방은 최대 과제중의 하나이다. 일반적으로 하기주간의 냉방방법으로는 냉동기(또는 냉수)에 의한 것과 세무의 증발냉각에 의한 것으로 나누어 볼 수 있다. 필자 등은 1992년 일본 식물공장학회지에 Heat pump를 이용한 냉수냉방과 세무냉방을 이용한 국소냉방의 주요 결과중의 하나는 세무냉방에서의 토마토 과실에 송풍한 구에서는 배꼽썩이가 방지되었고, 무송풍구에서는 55% 배꼽썩이가 발생되었다. (중략)

• Agricultural and Biosystems Engineering
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• v.6 no.2
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• pp.54-58
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• 2005

In this study, tele-robotics was researched to actualize robots in agriculture. The robot system consisted of a data collecting robot, several robots that performed their own agricultural operations, a server, client computers and networks between robots and computers. In this paper, as a first step, harvesting experiments were carried out. From the results, it was observed that the tele-robotics had feasibility to propel the robotization in agriculture. The tele-robotics has advantages not only that human workers are released from the severe working environment but also that the greenhouse can be monitored and controlled anytime and anywhere.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1999.11a
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• pp.164-168
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• 1999

온실은 동절기 난방을 주목적으로 설비되어 년중 작물재배 시는 하절기 온실내부 온도가 필요이상으로 상승하여 실내온도가 35-4$0^{\circ}C$ 정도로 올라가는데 이러한 상태에서의 온도는 많은 작물의 생육적온을 벗어난 온도로서 고온장해를 나타낸다. 이 같은 문제점을 해결하기 위해 몇 가지 냉방방법이 알려져 있는데 에어컨 등과 같은 냉방장치를 이용한 기계적 냉각방식과 수분증발을 통한 증발식 냉각방식으로 대별되며 이중 기계적인 냉방방식은 설비나 유지관리 면에서 비용이 많이 들어 비경제적이고, 증발냉각 방식중에서도 Fan and Pad 법이 가장 효과가 좋은 것으로 알려져 있으나 이역시 설치 및 유지비가 많이 들고, vep의 탈부착이 어려워 고정시켜놓을 경우 동계 광투과에 방해가 되는 등의 문제가 많다. (중략)

• Korean Journal Plant Pathology
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• v.10 no.1
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• pp.25-28
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• 1994

One hundred fifty four our of 262 isolates of Fusarium oxysporum obtained from healthy plant tissues of various crops and their rhizosphere soil were found to be nonpathogenic to cucumber plants. The nonpathogenic isolates were frequently found from sesame plant tissues and rhizosphere soil, but less from healthy plant tissues of cucumber and water melon. When the 154 nonpathogenic isolates were preinoculated into cucumber seedlings, and then challenge-inoculated with Fusarium wilt pathogen, 21 isolates protected effectively cucumber plants from Fusarium wilt infections. A year later, 9 out of 21 isolates fully sustained their protective effect. Among 9 isolates showing good protective effects, 7 were isolates from cucumber plants. These 9 isolates except 1 isolate, were not pathogenic to water melon, chines melon, tomato and sesame.

• Korean Journal Plant Pathology
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• v.10 no.1
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• pp.29-33
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• 1994

One hundred fifty four out of 262 isolates of Fusarium oxysporum obtained from healthy plant tissues of various crops and their rhizosphere soil were found to be nonpathogenic to cucumber plants. The nonpathogenic isolates were frequently found from sesame plant tissues and rhizosphere soil, but less from healthy plant tissues of cucumber and water melon. When the 154 nonpathogenic isolates were preinoculated into cucumber seedlings, and then challenge-inoculated with Fusarium wilt pathogen, 21 isolates protected effectively cucumber plants from Fusarium wilt infections. A year later, 9 out of 21 isolates fully sustained their protective effect. Among 9 isolates showing good protective effects, 7 were isolates from cucumber plants. These 9 isolates, except 1 isolate, were not pathogenic to water melon, chinese melon, tomato and sesame.

• Korean Journal of Weed Science
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• v.30 no.4
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• pp.412-420
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• 2010

Weeds are known to cause enormous losses due to their interference in agro ecosystems. Because of environmental and human health concerns, worldwide efforts are being made to reduce the heavy reliance on synthetic herbicides that are used to control weeds. In this regard phytotoxicity of allelochemical sorgoleone, which is a major component of the hydrophobic root exudates of Sorghum bicolor was evaluated in different weed species and also its crop selectivity in greenhouse and field conditions. Sorgoleone strongly inhibited the growth of different weeds by pre-emergence and post-emergence applications both in greenhouse and field conditions. Post-emergence application of sorgoleone on 21-day-old weed seedlings had a greater inhibitory effect than the pre-emergence application. Again, broadleaf weed species were more susceptible than grass species to the application of sorgoleone at both stages of growth. Growth of broadleaf weed species was suppressed by greater than 80% for most of the weed species except a few species and among them the species Rumex japonicus and Galium spurium were completely suppressed at $200{\mu}g\;ml^{-1}$ sorgoleone. Like greenhouse trial, sorgoleone was more effective for broadleaf weed species followed by sedge and grass weed species in the field condition. The growth inhibition of weeds was slightly lower in field condition compared to greenhouse condition. The crop species like rice, barley, wheat, corn, perilla, tomato, soybean and Chinese cabbage were tolerant to sorgoleone while lettuce and cucumber were slightly susceptible to sorgoleone. Consequently, sorgoleone may be applied to control weeds in organic farms without affecting the growth of crop.

• Journal of Bio-Environment Control
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• v.29 no.4
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• pp.428-439
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• 2020

This study was carried out to investigate the effect of PO film on the increase of crop yield and energy saving through PO and PE film greenhouse application and comparison test. As a experimental greenhouse, two single span greenhouses (1-1 W) and two double span greenhouses (1-2 W) were used. During winter season, PO film (0.15 mm outer layer, 0.10mm inner layer) was used as a covering material of greenhouse in double layers for double-span (B15) and single-span(B21), and PE film used for double-span (B15), and single-span (B23) as a control. The experimental vegetable was tomato(Solanum lycopersicum L.) cultivated in soil and the cultivar of that was 'Happiness'. That was cultivated from December 3, 2019 to April 30, 2020. The temperature at night inside the greenhouse was maintained at 15℃, and the side and roof windows were opened to maintain 23 ~ 24℃ during the day. As a result, this study showed that the yield in single-span greenhouse(B21) covered with a PO film increased 20% and that in double-span greenhouse (B16) increased by 9% compared to the greenhouse covered with a PE film (B23, B15). Fuel consumption of the single-span greenhouse (B21) with the cover of PO film was reduced by 12.4% and that of double-span greenhouse was done by 11.5% compared to that of the PE film greenhouse (B23, B15) without any difference between them in growing state.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.3
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• pp.225-233
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• 1991

This study was conducted to evaluate the potential of indigenous vesicular-arbuscular mycorrhizal fungi(VAMF) in the rhizosphere soil of horticultural crops grown under greenhouse and open-field condition, in the southern area of Kores. Soil samples collected from the rhizosphere of some sellected horticultural crops, such as cucumber, hot pepper, lettuca, tomato and eggplant grown under greenhouse or open-field condition. All tested crops are considered as mycorrhizal plants. The infection rate of horticultural crops investigated ranged from 38% to 70%, hot pepper and eggplant grown under greenhouse condition showed the highest infection being 66.0% and 70.0%, respectively. Spore densities were from 4.8 to 20.0g-1 on dried soil basis. Spore densities of VAMF in the rhizosphere soils under greenhouse condition were higher than that of open-field conditions. The highest distribution of spores in diameter ranged from $75{\mu}m$ to $106{\mu}m$ in the rhizosphere soil of lettuce, cucumber and tomato while those in hot pepper and eggplant ranged from $75{\mu}m$ to $250{\mu}m$. Glomus sp.-type spores predominated in the slightly acid soil(pH 6.3), while Acaulospora sp.-type spores greatly predominated in the very strongly acid field(pH 4.9).

• Journal of Bio-Environment Control
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• v.15 no.4
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• pp.296-305
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• 2006

The heterogeneity of crop transpiration is important to clearly understand the microclimate mechanisms and to efficiently handle the water resource in greenhouses. A computational fluid dynamic program (Fluent CFD version 6.2) was developed to study the internal climate and crop transpiration distributions of greenhouses. Additionally, the global solar radiation model and a crop heat exchange model were programmed together. Those models programmed using $C^{++}$ software were connected to the CFD main module using the user define function (UDF) technology. For the developed CFD validity, a field experiment was conducted at a $17{\times}6 m^2$ plastic-covered mechanically ventilated single-span greenhouse located at Pusan in Korea. The CFD internal distributions of air temperature, relative humidity, and air velocity at 1m height were validated against the experimental results. The CFD computed results were in close agreement with the measured distributions of the air temperature, relative humidity, and air velocity along the greenhouse. The averaged errors of their CFD computed results were 2.2%,2.1%, and 7.7%, respectively.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.266-274
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• 2010

This study aim to investigate fundamentally the growth and physiological responses of tomato plants in responses to two different levels of water deficit, a weak drought stress (-25 kPa) and a severe drought stress (-100 kPa) in soil. The two levels of water deficit were maintained using a micro-irrigation system consisted of soil sensors for the real-time monitoring of soil water content and irrigation modules in a greenhouse experiment. Soil water contents were fluctuated throughout the 30 days treatment period but differed between the two treatments with the average -47 kPa in -25 kPa set treatment and the -119 kPa in -100 kPa set treatment. There were significant differences in plant height between the two different soil water statuses in plant height without differences of the number of nodes. The plants grown in the severe water-deficit treatment had greater accumulation of biomass than the plants in the weak water-deficit treatment. The severe water-deficit treatment (-119 kPa) also induced greater leaf area and leaf dry weight of the plants than the weak water-deficit treatment did, even though there was no difference in leaf area per unit dry weight. These results of growth parameters tested in this study indicate that the severe drought could cause an adaptation of tomato plants to the drought stress with the enhancement of biomass and leaf expansion without changes of leaf thickness. Greater relative water content of leaves and lower osmotic potential of sap expressed from turgid leaves were recorded in the severe water deficit treatment than in the weak water deficit treatment. This finding also postulated physiological adaptation to be better water status under drought stress. The drought imposition affected significantly on photosynthesis, water use efficiency and stomatal conductance of tomato plants. The severe water-deficit treatment increased PSII activities and water use efficiency, but decreased stomatal conductance than the weak water-deficit treatment. However, there were no differences between the two treatments in total photosynthetic capacity. Finally, there were no differences in the number and biomass of fruits. These results suggested that tomato plants have an ability to make adaptation to water deficit conditions through changes in leaf morphology, osmotic potentials, and water use efficiency as well as PSII activity. These adaptation responses should be considered in the screening of drought tolerance of tomato plants.