• Journal of Bio-Environment Control
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• v.22 no.1
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• pp.7-12
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• 2013

Environmental measurements in the many different types of horticultural farms were carried out to evaluate the ventilation performance for multi-span plastic greenhouses according to the eaves height, the number of spans, the existence of side wall vents and the position of roof vents. Hydroponic tomatoes were being cultivated in all experimental greenhouses, and ventilation rates of the greenhouses were analyzed by the heat balance method. It showed that the ventilation rate in the greenhouse with 4 m eaves height increased about 22% compared to the greenhouse with 2 m eaves height. The ventilation rate in the greenhouse with 9 spans decreased about 17% compared to the greenhouse with 5 spans. In the greenhouse with 9 spans, if there were no side wall vents, the ventilation rate showed about a third of the case that side wall vents were open. Overall, as the eaves height was higher and the number of spans was smaller in multi-span greenhouses, the natural ventilation performance was better. And the ventilation performance was best in the greenhouse which the eaves height was high and the position of roof vents was ridge, not gutter. Therefore, in order to maximize the natural ventilation performance, multi-span plastic greenhouses need to improve their structures such as that make the eaves height higher, place the roof vents on the ridge, install the side wall vents as much as possible, and the number of spans is limited to about 10 spans.

• Journal of Environmental Science International
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• v.25 no.8
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• pp.1115-1129
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• 2016

To analyze human thermal environments in protected horticultural houses (plastic houses), human thermal sensations estimated using measured microclimatic data (air temperature, humidity, wind speed, and solar and terrestrial radiation) were compared between an outdoor area and two indoor plastic houses, a polyethylene (PE) house and a polycarbonate (PC) house. Measurements were carried out during the daytime in autumn, a transient season that exhibits human thermal environments ranging from neutral to very hot. The mean air temperature and absolute humidity of the houses were $14.6-16.8^{\circ}C$ (max. 22. $3^{\circ}C$) and $7.0-12.0g{\cdot}m^{-3}$ higher than those of the outdoor area, respectively. Solar (K) and terrestrial (L) radiation were compared directionally from the sky hemisphere (${\downarrow}$) and the ground hemisphere (${\uparrow}$). The mean $K{\downarrow}$ and $K{\uparrow}$ values for the houses were respectively $232.5-367.8W{\cdot}m^{-2}$ and $44.9-55.7W;{\cdot}m^{-2}$ lower than those in the outdoor area; the mean $L{\downarrow}$ and $L{\uparrow}$ values were respectively $150.4-182.3W{\cdot}m^{-2}$ and $30.5-33.9W{\cdot}m^{-2}$ higher than those in the outdoor area. Thus, L was revealed to be more influential on the greenhouse effect in the houses than K. Consequently, mean radiant temperature in the houses was higher than the outdoor area during the daytime from 10:45 to 14:15. As a result, mean human thermal sensation values in the PMV, PET, and UTCI of the houses were respectively $3.2-3.4^{\circ}C$ (max. $4.7^{\circ}C$), $15.2-16.4^{\circ}C$ (max. $23.7^{\circ}C$) and $13.6-15.4^{\circ}C$ (max. $22.3^{\circ}C$) higher than those in the outdoor area. The heat stress levels that were influenced by human thermal sensation were much higher in the houses (between hot and very hot) than in the outdoor (between neutral and warm). Further, the microclimatic component that most affected the human thermal sensation in the houses was air temperature that was primarily influenced by $L{\downarrow}$. Therefore, workers in the plastic houses could experience strong heat stresses, equal to hot or higher, when air temperature rose over $22^{\circ}C$ on clear autumn days.

• Journal of Wetlands Research
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• v.18 no.4
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• pp.386-393
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• 2016

Agricultural ecosystem is recognized as a space for providing a variety of services, in addition to the food production that it originally encompassed, such as water purification, biological habitat, air purification, soil conservation, and landscape development. The construction of greenhouses in agricultural landscapes can cause deterioration of ecosystem services because of the increase of impermeable area and loss of biological habitats. This study aimed to compare insect diversity between different types of constructed greenhouses and paddy ecosystems. The target study area was selected by considering the distribution status of horticultural complexes and was classified as Single Vinyl Greenhouse, Multi Vinyl Greenhouse or Glass Greenhouse and they were compared with four paddies. The study locations were in Gu-Mi, Bu-Yeo, Ginje and Jin-Ju. A total of 2,333 individual insects belonging to 9 orders, 38 families, 76 genus, and 80 species were collected. The composition of orders was Hemiptera (22.37%), Coleoptera (18.42%), Hymenoptera (14.47%), Orthoptera (11.84%), and Diptera (10.53%). The average number of collected species were in the order Paddy (39.38 species) > Single Vinyl Greenhouse (35.50 species) > Multi Vinyl Greenhouse (22.50 species) > Glass Greenhouse (24.00 species). The Diversity Index (H') was Paddy (4.76) > Single Vinyl Greenhouse (4.57) > Multi Vinyl Greenhouse (4.12), and Glass Greenhouse (4.12). The Richness Index (RI) was Paddy (7.72) and Single Vinyl Greenhouse (7.03) > Multi Vinyl Greenhouse (4.99) and Glass Greenhouse (5.32). From our results, it can be seen that the biological diversity features of insects decreased when greenhouses are constructed.However, Single Vinyl Greenhouse is noted to promote insect diversity more than that by Multi Vinyl Greenhouse and Glass Greenhouse. Hence, when constructing greenhouses, it is necessary to consider insect habitat to conserve insect diversity.

• Journal of Bio-Environment Control
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• v.27 no.1
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• pp.80-85
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• 2018

This study was carried out to clarify the effect of CHO-CO and PO film on air temperature in greenhouse and Korean melon fruit characteristics and yield. On January 8 in 2017, the maximum, minimum and average air temperature in greenhouse covered with CHO-CO film were $38.9^{\circ}C$, $13.4^{\circ}C$ and $20.1^{\circ}C$, respectively. At the same date, the maximum, minimum and average air temperature in greenhouse covered with PO film were $40.0^{\circ}C$, $14.9^{\circ}C$ and $20.3^{\circ}C$, respectively. On August 7 in 2017, the maximum, minimum and average air temperature in greenhouse covered with CHO-CO film were $47.2^{\circ}C$, $23.1^{\circ}C$ and $32.4^{\circ}C$, respectively, and the maximum, minimum and average air temperature in greenhouse covered with PO film were $50.3^{\circ}C$, $23.6^{\circ}C$ and $34.0^{\circ}C$, respectively. The results of investigation of qualities and yields of Korean melons from May 26 to August 15 in 2017 were as follows. The fruit weight of Korean melon harvested in CHO-CO film's greenhouse was 371.6g which was 22.2g less than that of PO film greenhouse. The sugar contents of Korean melon harvested in CHO-CO film greenhouse was $14.5^{\circ}brix$ which was $1.4^{\circ}brix$ greater than that of the fruits harvested in PO film greenhouse. The chromaticity (a-value) of fruit skin of Korean melon harvested in CHO-CO film greenhouse was 12.3 which was 1.5 greater than that of the fruits harvested in PO film greenhouse. The marketable yield rate of Korean melon harvested in CHO-CO film's greenhouse was 89.4% which was 8.0% higher than the fruits harvested in PO film greenhouse. The yield of Korean melon harvested in CHO-CO film's greenhouse was 2694kg per 10 a which was 26% more than that harvested in PO film greenhouse. In conclusion, the CHO-CO film could be effective to produce Korean melon in high temperature season.

• Horticultural Science & Technology
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• v.35 no.1
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• pp.69-78
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• 2017

This study was conducted to investigate the effects of waterlogging on the net photosynthetic rate, root activity and fruit yield of hot pepper. Plants were grown in two greenhouses: extractor fans and side ventilators began to operate when the inside temperature reached $25^{\circ}C$ in one greenhouse and $35^{\circ}C$ in the other. Waterlogging treatments were performed 54 days after transplanting (when fruit setting at the second flower truss was complete). The plot in each greenhouse was divided into five sections, and each section was watered for 0, 12, 24, 48 or 72 h using drip irrigation. Plants under $25^{\circ}C$ and non - waterlogging treatment exhibited in the greatest growth among treatments. Plant growth generally decreased as the waterlogging period increased. The net photosynthetic rate was highest under non - waterlogging and $25^{\circ}C$ treatment and lowest under 72 h waterlogging and $25^{\circ}C$ treatment. The root activity decreased as the waterlogging period increased, except for plants under 72 h waterlogging treatment at $35^{\circ}C$. The number and weight of red pepper fruits per plant were highest under non - waterlogging treatment at $35^{\circ}C$. The greatest fruit yield was also observed under non - waterlogging treatment at $35^{\circ}C$, with production reaching 3,697 kg / 10a. At the appropriate temperature for hot pepper ($25^{\circ}C$), yields were reduced by 25 - 30% under 12, 24 and 48 h waterlogging treatment compared to non - waterlogging treatment. These results indicate that longer waterlogging periods reduce the growth, net photosynthetic rate, root activity and yields of hot pepper. However, the net photosynthetic rate and stomatal conductance of hot pepper plants grown under 72 h waterlogging treatment recovered nine days after growth under normal growth conditions.

• Horticultural Science & Technology
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• v.31 no.1
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• pp.56-64
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• 2013

Recent unusual weather due to global warming causes shortage of daily sunlight and constitutes one of the primary reasons for agricultural damages. LED light sources are frequently utilized to compensate for the shortage of sunlight in greenhouse agriculture. The present study is aimed at evaluating formations of phytochemicals as well as growth characteristics of mature strawberry fruits ('Daewang' cultivar) during cultivation in a closed growth chamber equipped with artificial LED light as a sole light source. Each LED light of blue (448 nm), red (634 and 661 nm) or mixed blue plus red (blue:red = 3:7) was separately supplied and the intensity of each light was adjusted to $200{\pm}1{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ at plant level with a photoperiod consisted of 16 hours light and 8 hours darkness. Strawberries grown under mixed LED light of blue and red wavelengths showed a higher production of fruits than those grown under other LED treatments. Fructose, one of the free sugars, increased in mixed LED light-grown fruits. Anthocyanin contents were elevated remarkably in the mixed LED light-grown fruits compared with those in other LED treatments. Contrastingly, contents of total phenolics and flavonoids were not of much different from one another among the fruits treated with various LED lights. On the other hand, ripening of strawberry fruits was found to be faster when grown under blue LED light compared with other LED treatments. Moreover, antioxidant activities of blue or red LED light-grown fruits, respectively, were significantly higher than those of mixed LED light-grown fruits. We suggest that when daylight is in shortage during cultivation in a greenhouse, supplementation of sunlight with LED light, which is composed of blue and red wavelengths, could be useful for the enhancement of productivity as well as of free sugar content in strawberry fruits. In addition, for the strawberry culture in the plant factory, selective adoption of LED light wavelength would be required to accomplish the purpose of controlling fruit maturation time as well as of enhancing contents of sugars and antioxidants of fruits.

• Journal of Plant Biotechnology
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• v.45 no.4
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• pp.382-391
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• 2018

The objective of this study was to determine the most effective medium condition of shoot proliferation and root formation for the efficient in vitro micropropagation of M.26 (Malus pumila Mill). Simple sequence repeat (SSR) markers were used to analyze the genetic diversity of micro-propagated and greenhouse grown M.26. Shoot proliferation was carried out in MS (Murashige and Skoog) containing benzyladenin (BA, $0.5{\sim}5.0mg{\cdot}L^{-1}$) and thidiazuron (TDZ, $0.01{\sim}0.1mg{\cdot}L^{-1}$). The highest number of shoots (10.67 shoots per explant) was induced by adding BA at a concentration $1.0mg{\cdot}L^{-1}$. TDZ treatments caused higher hyperhydricity rate in cultured explants than in BA treatments. There was no significant effect of both BA and auxin on shoot proliferation, and the optimum proliferation medium for M.26 was MS medium containing $1.0mg{\cdot}L^{-1}$ BA. To find a suitable medium composition for shoot rooting, we tested different concentrations indole-3-butyric acid (IBA) and ${\alpha}$-naphthaleneacetic acid ($0.5{\sim}5.0mg{\cdot}L^{-1}$), MS medium (1/4-1), sucrose ($0{\sim}30g{\cdot}L^{-1}$). The shoots showed good rooting on half-strength MS medium containing $1.0mg{\cdot}L^{-1}$ IBA and $15-20g{\cdot}L^{-1}$ sucrose. The rooting rate (100%), number of roots (10.45 ~ 13.60 roots per explant), root length (7.41 ~ 8.33 cm), and shoot length (4.93 ~ 5.38 cm) were good on this medium. Fifteen SSR primers were detected in a total of 30 alleles in 20 micro-propagated plantlets, all SSR profiles from micro-propagated plantlets were monomorphic and similar to greenhouse grown control plantlet M.26 plant. The results indicated that M.26 micro-propagated plantlets were genetically stable.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.12
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• pp.3-10
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• 2018

Recently, severe damage to domestic horticultural structures is frequently observed due to extreme climate effects. To minimize the structures' damage, a study on the structural stability of multi-span vinyl greenhouses is needed. This paper presents to measure the rotational stiffness of different connectors to improve the design capacities of the specification. The paper investigated fourteen types of the different connectors, which was commonly used in the multi-span greenhouses, and three different types of the connectors predicted to be under moment-connection were selected: i) T-clamp, ii) U-clamp, iii) C-clamp. Static loading tests for three different connectors were performed to measure the rotational stiffness. Additionally, the boundary condition for the structural design was proposed based on the experimental results of the rotational stiffness. One of three connectors, C-clamp had larger rotational stiffness than other connectors, and the experimental results presented the three connectors had boundary conditions; i) T-clamp was pinned-connection, ii) U-clamp was semi-rigid connection, iii) C-clamp was semi-rigid connection.

• Horticultural Science & Technology
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• v.33 no.5
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• pp.633-637
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• 2015

Cucumber and paprika transplants were stored at 9, 12, 15, and $18^{\circ}C$ under dark conditions for 15 days and then grown in a greenhouse for 14 days after transplanting. To determine the effects of low storage temperature and long-term continuous darkness on the quality and vigour of transplants, we investigated the quality of transplants during storage and the growth of stored transplants after transplanting. In cucumber transplants, decreasing storage temperature reduced stem elongation and decrease in SPAD value. The quality of cucumber transplants stored at $9^{\circ}C$ was well preserved during storage, but they did not survive after transplanting due to chilling damage. Growth and development after transplanting were significantly greater when cucumber transplants were stored at $12^{\circ}C$. In paprika transplants, the quality of transplants did not significantly differ before and after storage. After transplanting, there was no significant difference in the survival rate and growth, but the number of flower buds was greater in the paprika transplants stored at lower temperatures (9 and $12^{\circ}C$). These results indicate that the responses of transplants to the conditions of low temperature and darkness differed between cucumber and paprika, and storage temperature in darkness must be controlled carefully considering species-specific responses to reduce quality deterioration during storage and improve the recovery of transplants after transplanting.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.4
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• pp.293-301
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• 1991

Spores of the family Clomaceae, Acaulosporaceae. and Gigasporaceae in the ord er Clomales. isolated from greenhouse soils grown horticultural crop in the southern region of Korea, included those of the following species : Acaulospora biretculata Rothwell & Trappe, A. appendiculata Spain, Sievering & Schenck, A. foveata Trappe & Janos, A. denticulata Sievering and Toro. A. elegans Trappe & Gerd., A. rehmii Sieverding & Toro in Acaulospora species, Gigaspora gigantea (Nicol. & Gerd.) Cerd. & Trappe, G. decipiens Hall & Abbott in Gigaspora species, Glomus ambisporum Schenck & Smith, G. hoi Berch & Trappe, G. caledoniwn (Nicol. & Gerd.) Trappe & Gerd. in Glomus species, Scutellispora aurigloba (Hall) Walker & Sanders, S. calospora (Nicol. & Gerd.) Walker & Sanders, S. coralloidea (Trappe, Gerd. & Ho) Walker & Sanders in Scutellispora species. Sporocarps of Sclerocystis pachycaulis Wu & Chen were also found.