• Journal of Bio-Environment Control
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• v.19 no.1
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• pp.6-11
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• 2010

This experiment was conducted to investigate the effect of greenhouse orientation on the greenhouse environment and the growth and yield of tomato cv 'Momotaro-Yoku' in forcing culture. The photosynthetic phpton flux density (PPFD) of a.m was higher in north-south orientation than that in east-west orientation and it was opposed in the p.m. Mean PPFD of a day was higher in east-west orientation than that in north-south orientation because the light transmitting area became larger in east-west orientation with decrease of incidence angle. The PPFD at 60 cm point above ground of all furrows was poor due to shadows near plants and it was higher in north-south orientation than that in east-west orientation. The air temperature in the greenhouse was higher in east-west orientation than that in north-south orientation but there was no significant difference since mid February as solar altitude goes up. The soil temperature was some higher in east-west orientation than that in north-south orientation and there was not significant difference among ridges. In east-west orientation, as ripening was promoted, high early yield of tomato were obtained. So total yield was greater about 8% in east-west orientation than that in north-south orientation. Therefore, it was considered that east-west orientation is more advantageous than north-south orientation for forcing culture of tomato.

• Journal of Biosystems Engineering
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• v.23 no.5
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• pp.439-444
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• 1998

Effects of the number of spans, orientation and latitude on the transmissivities of direct and diffuse solar radiation in multispan glasshouse were analyzed using a computer simulation model (Kim and Lee, 1997). The number of spans did not affect the transmissivity of diffuse solar radiation, ranging 60∼61%. The transmissivities of direct solar radiation were 55∼64% for E-W orientation and 47∼70% for N-S orientation in ten multispan glasshouse. There was no effect of the latitude on the transmissivity of direct solar radiation in domestic regions. Differences in the transmissivity of direct solar radiation between single-span and multispan glasshouse were significant for E-W orientation during winter season; however, those were relatively small for N-S orientation throughout the year. Transmissivity of direct solar radiation decreased with the increasing number of spans for E-W glasshouse, whereas those for N-S glasshouse was hardly affected by the number of spans.

• Magazine of the Korean Society of Agricultural Engineers
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• v.36 no.3
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• pp.84-89
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• 1994

Section forces of greenhouse structures were studied to suggest basic information for the structural design of greenhouses with respect to roof types and support conditions. Structural analyses were performed for pitched and arched roof, and fixed and hinged support under snow loads and wind loads. Followings are the results obtained and are expected to be useful in determining the span length and roof type in greenhouse design. 1. Special considerations might he required for roof design at the heavy snow region, and for the support design at the strong wind region, respectively. 2. Single-span structure was found to be stronger than multi-span structure under the snow load, but the former was found to be weaker than the latter under the wind load. 3. Arched roof structure was expected to be safer than pitched roof structure if the dimensions and loads were equal. 4. Greenhouse orientation and roof slope should be considered in optimum structural design of grrenhouses, because these two factors are closely related with the influence of wind load and snow load.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.3
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• pp.349-356
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• 2022

Currently, the agricultural population in Korea indicates a decreasing and aging orientation. As the population of farm labor continues to decline, so farmers are feeling the pressure to be stable crop production. To solve the problem caused by the decreasing of farm labor, it is necessary to change over to "Digital agriculture". Digital agriculture is tools that digitally collect, store, analyze, and share electronic data and/or information in agriculture, and aims to integrate the several digital technologies into crop and livestock management and other processes in agriculture fields. In addition, digital agriculture can offer the opportunity to increase crop production, save costs for farmer. Therefore, in this study, for data-based Digital Agriculture, a greenhouse environment monitoring system for crop growth monitoring based on Node-RED, which even beginners can use easily, was developed, and the implemented system was verified in a hydroponic greenhouse. Several sensors, such as temperature, humidity, atmospheric pressure, CO₂, solar radiation, were used to obtain the environmental data of the greenhouse. And the environmental data were processed and visualized using Node-RED and MariaDB installed in rule.box digital. The environment monitoring system proposed in this study was installed in a hydroponic greenhouse and obtained the environmental data for almost two weeks. As a result, it was confirmed that all environmental data were obtained without data loss from sensors. In addition, the dashboard provides the names of installed sensors, real time environmental data, and changes in the last three days for each environmental data. Therefore, it is considered that farmers will be able to easily monitor the greenhouse environment using the developed system in this study.

• Horticultural Science & Technology
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• v.32 no.4
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• pp.473-483
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• 2014

In this work, the effects of shade combination, shade height and wind regime on greenhouse climate were quantified. A two-dimensional (2-D) computational fluid dynamics (CFD) model was developed based on an 11-span plastic greenhouse in eastern China for wind almost normal to the greenhouse orientation. The model was first validated with air temperature profiles measured in a compartmentalized greenhouse cultivated with mature lettuce (Lactuca sativa L., 'Yang Shan'). Next, the model was employed to investigate the effect of shade combinations on greenhouse microclimate patterns. Simulations showed similar airflow patterns in the greenhouse under different shade combinations. The temperature pattern was a consequence of convection and radiation transfer and was not significantly influenced by shade combination. The use of shade screens reduced air velocity by $0.02-0.20m{\cdot}s^{-1}$, lowered air temperature by $0.2-0.8^{\circ}C$ and raised the humidity level by 0.9-2.0% in the greenhouse. Moreover, it improved the interior climate homogeneity. The assessment of shade performance revealed that the external shade had good cooling and homogeneity performance and thus can be recommended. Furthermore, the effects of external shade height and wind regime on greenhouse climate parameters showed that external shade screens are suitable for installation within 1 m above roof level. They also demonstrated that, under external shade conditions, greenhouse temperature was reduced relative to unshaded conditions by $1.3^{\circ}C$ under a wind speed of $0.5m{\cdot}s^{-1}$, whereas it was reduced by merely $0.5^{\circ}C$ under a wind speed of $2.0m{\cdot}s^{-1}$. Therefore, external shading is more useful during periods of low wind speed.

• Journal of Biosystems Engineering
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• v.22 no.3
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• pp.325-332
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• 1997

The use of a robotic transplanter reduces the labor requirement in the greenhouse by carrying out repetitive tasks in an accurate and reliable manner. The transplanter manipulates seedlings by means of end-effector. The end-effector is designed differently from an industrial robot because it manulates biological seedlings of variable size, shape, position, and orientation. This study was conducted to develop an end-effector of a robotic transplanter for bedding plants. The development of an end-effector included selection of the best finger type for the transplanting operation. The performance of developed end-effector was tested and compared with two different transplanting schemes depending on the leaf-orientation consideration. The end-effector developed in this research reliably handled seedlings during transplanting task. Results showed that the shovel type finger was suitable for transplanting with the damaging seedlings.

• Journal of Bio-Environment Control
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• v.25 no.2
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• pp.83-88
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• 2016

In this study, previously reported surplus solar energy-related study result and current status of fan coil unit (FCU) for cooling and heating installed in the current sites were briefly examined and then a method to determine the number of FCUs required to recover surplus solar energy was schematically proposed to provide basic data for researchers and technical engineers in this field. The maximum, mean, and minimum outside temperatures during the experiment period were about $28.2^{\circ}C$, $4.4^{\circ}C$, and $-11.5^{\circ}C$, respectively. The horizontal surface solar radiation level outside the greenhouse was in a range of $0.8-20.5MJ{\cdot}m^{-2}$ and mean and total solar radiation were $10.8MJ{\cdot}m^{-2}$ and $1,187.5MJ{\cdot}m^{-2}$. The mean temperature and relative humidity in the greenhouse during the daytime were in a range of 18.8-45.5 and 53.5-77.5%. The total surplus solar energy recovered from the greenhouse during the experiment period was approximately 6,613.4MJ, which could supplement about 6.7% of the total heating energy 98,600.2 MJ. In addition, the number of FCUs installed for heating varies case to case, although similar FCUs are used. Thus, it is necessary to study the installation height, orientation and installation distance as well as the appropriate number of FCUs from the efficient and economical viewpoints. The required numbers of FCUs for surplus solar energy recovery were 8.4-10.9units and 6.1-8.0units based on air mass and circular flow rate that passed through the FCUs. Considering calculation methods and the risks such as efficiency and use environments of FCUs, it was found that about nine units (one unit per $24m^3$ approximately) needed to be installed. The required number of FCUs for surplus solar energy recovery was around one unit per $24m^3$ approximately.

• Horticultural Science & Technology
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• v.32 no.2
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• pp.133-141
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• 2014

Due to limited supplies and expensive importing costs, it is a goal to replace overseas peat with local soil amendments in turf industry of Korea. The study was initiated to compare the performances of five domestic and imported organic soil amendments (OSAs) on establishment characteristics and to provide basic information for root zone composition on sports turf design and construction. The study was conducted in Kentucky bluegrass (Poa pratensis L., KB) under greenhouse conditions from March to June in 2008. A total of 25 treatments of OSA + sand were prepared. These amendments were Berger Peat (OMA), Eco-Peat (OMB), G1-Soil (OMC), Premier Peat (OMD), and Supersoil I (OME). Significant differences were observed in establishment vigor, seedling emergence, and top growth. Results varied depending upon the type of OSAs and their rates in rootzone mixtures. OMA reached over 70% in establishment vigor in 5 WAS (weeks after seeding). OMC produced a maximum vigor of approximately 60% in 6 WAS. The OME amendment, however, showed poor performance lower than 30% in establishing KB turf until 8 WAS. There were considerable variations of top growth, being 3.8 to 14.5 cm. Greater differences in top growth resulted from OME mixtures. Shoot growth orientation in KB is also influenced by OSAs. In general, optimum mixing rate was considered as 10 to 20% for establishment vigor and 20 to 40% for top growth. Considering overall responses to establishment vigor, seedling emergence, and shoot growth, both local OMC and overseas OMD are considered as the useful soil amendments applicable for sports turfs. Domestic OME amendment would be applied for a low maintenance turfs such as rough and utility areas due to greater shoot growth. Information on these amendments would be of practical use for sports turf design and construction. Repeated experiments and field performance test are required to evaluate these OSA effect on other major turfgrass species and also to determine local OSA as imported peat substitute.

• Korean Journal of Plant Tissue Culture
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• v.26 no.1
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• pp.59-63
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• 1999

Efficient plant regeneration via shoot organogenesis from in vitro cultured leaf segments of chrysanthemum (Dendranthema grandiflora Tzvelev cv. Namjeon) was achieved. Adventitious shoot formation from leaf explants was greatly influenced by plant growth regulator, leaf age, light condition, explant number per culture vessel, and explant orientation. Leaf segments, obtained from fully expanded young 1-2nd leaves and inoculated 8 explants per petri-dish with adaxial surface contact with MS medium supplemented with 0.5 mg/L BA and 2.0 mg/L NAA, produced 100% regeneration frequency and 13.7 shoots per explant. Regenerated adventitious shoots were successfully rooted in MS medium with 0.1 mg/L NAA. The plantlets were acclimatized in artificial soil mixtures (Vermiculite:Perlite=1:1), and transferred to greenhouse for flowering. The regenerated plants showed normal phenotypes.

• Korean Journal Plant Pathology
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• v.3 no.2
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• pp.100-107
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• 1987

Pre-pentration activity of Pyricularia oryzae Cav. from the stage of conidia germination to appressorium formation was examined on rice leaf epidermis under light and scanning electron microscopes to determine the causes· for differences in blast susceptibility between plants grown under three different soil moisture conditions in the greenhouse. No significant differences were found in the external shape of leaf epidermal cells including bulliform cells between plants grown under different soil moisture conditions. Growth and orientation of germ tube and morphology and size of appressorium of P. oryzae did not vary with soil moisture treatment. Site of appressorium formation was consistent over soil moisture treatment with the highest frequency of bulliform cell $(35\~48\%)$, followed by short cell $(19\~27\%)$, and long and guard cells $(13\~20\%)$. No appressorium was formed on trichome. This result suggests that the observed differences in blast susceptibility between plants grown under different soil moisture conditions were not due to the differences in the pre-pentration activity of P. oryzae on those plants.