• Proceedings of the Korean Society of Crop Science Conference
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• 1998.10a
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• pp.41-67
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• 1998

This study aimed at examining the investment and economic analysis of greenhouse horticultural project area by governmental subsidy project. There were only 5 project areas that economic efficiency of investment is recognized in 30 project area in Kyungsangnam-do. And there are 7 project areas to gain farm firm revenue. These were possible area to develop to farm firm. There are 4 project areas to gain farm firm revenue in 18 project areas of glass greenhouse area, and 8 project areas to gain farm firm revenue in 12 project areas-vinyl greenhouse area. The rate of return of the fixed capital is higher in the vinyl greenhouse area than in the glass greenhouse area by type of greenhouse. There were cultivated tomatoes, cucumbers, peppers, etc. in the greenhouse area. The investment efficiency of the fixed capital is higher in cucumber and pepper than in other vegetables. Flowers a re lower than the vegetable in investment efficiency.

• 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.

• Horticultural Science & Technology
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• v.34 no.6
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• pp.860-870
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• 2016

Continuous monitoring of environmental parameters provides farmers with useful information, which can improve the quality and productivity of crops grown in greenhouses. The objective of this study was to develop a greenhouse environment measurement system using a low-cost microcontroller with open-source software. Greenhouse environment parameters measured were air temperature, relative humidity, and carbon dioxide ($CO_2$) concentration. The ranges of the temperature, relative humidity, and $CO_2$ concentration were -40 to $120^{\circ}C$, 0 to 100%, and 0 to 10,000 ppm, respectively. A $128{\times}64$ graphic LCD display was used for real-time monitoring of the greenhouse environments. An Arduino Uno R3 consisted of a USB interface for communicating with a computer, 6 analog inputs, and 14 digital input/output pins. A temperature/relative humidity sensor was connected to digital pins 2 and 3. A $CO_2$ sensor was connected to digital pins 12 and 13. The LCD was connected to digital pin 1 (TX). The sketches were programmed with the Arduino Software (IDE). A measurement system including the Arduino board, sensors, and accessories was developed (totaling $244). Data for the environmental parameters in a venlo-type greenhouse were obtained using this system without any problems. We expect that the low-cost microcontroller using open-source software can be used for monitoring the environments of plastic greenhouses in Korea.

• Journal of Bio-Environment Control
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• v.10 no.4
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• pp.213-218
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• 2001

In 2000, domestic protected cultivation area was about 52,189 ha including 13,621 ha of heating greenhouses. Recently, heating cost accounts for 25 to 30% of total production cost which has been increased due to the rise of oil price, while the heating cost was about 15% in other advanced countries. To reduce the heating energy cost, the study of minimizing the heating space of greenhouse have been conducted from 1998 to 1999. The system was developed to control the heating space according to crop growth by moving horizontal curtain up and down. Installation of the heating space-control curtain in greenhouse decreased heating capacity to 264 m$^3$compared to 661.5 m$^3$in the traditional curtain, and consumpted fuel was saved about 56% point in semiforcing culture and 28% point in retarding culture of pepper. In addition, uniform distribution of air temperature and relative humidity in greenhouse environment resulted in earlier flowering and higher yields in hot pepper.

• Horticultural Science & Technology
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• v.30 no.5
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• pp.596-602
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• 2012

Infestations of Aphis gossypii per leaf in greenhouse cultivation of cucumbers were investigated to develop binomial sampling plans. An empirical $P_T-m$ model, $ln(m)={\alpha}+{\beta}ln[-ln(1-P_T)]$, was used to evaluate relationship between the proportion of infested leaves with ${\leq}$ T aphids per leaf ($P_T$) and mean aphid density (m). Tally thresholds (T) were set to 1, 3, 5, 7, and 9 aphids per leaf to find appropriate T in greenhouse cultivation of cucumbers. Increasing sample size had little effect on the precision of the binomial sampling plan. However, the precision increased with tally threshold. The binomial model with T = 5 provided appropriate predictions of the mean densities of A. gossypii in the greenhouse cultivation of cucumbers. Using a binomial model with T = 5 (sample size = 200), a wide range of densities (1.2 - 222.8 aphids per leaf) could be estimated with precision levels of 0.346 - 0.380 for $P_T$ values between 0.15 and 0.96. Binomial models were validated at T = 5 and 7 using 12 independent data sets. Both binomial models were robust and adequately described aphid densities; most of the independent sampling data fell within 95% confidence intervals around the prediction model.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.6
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• pp.81-87
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• 2017

The total area of domestic reclaimed lands is 54,379 ha, and among these, 30,394 ha can be agriculturally available. To increase an agricultural availability of reclaimed land, controlled horticultural products that can be highly profitable have come to the fore. However, as being characteristically concerning, when original glasshouse is intactly applied in reclaimed land, it is unsafe on account of ground subsidence and, even if ground were reinforced, it has a problem by high cost. So a new greenhouse model would be necessary taking into account not only cost-efficiency but also safety with relatively light-weight one. Before this, this paper estimated acceptance rate of controlled horticultural complexes in reclaimed land and new greenhouse model for 414 farmers. The annual rental fee is 129,712,500 won/ha, considering the interest rate (2.5 %) of the investment, the depreciation cost of the facilities (straight line depreciation method, 20 years of service life estimated), and government subsidy rate (50 %) which resulted in a sufficient number of intended tenants with the acceptance rate of 0.33. The results of this paper may contribute to the government's policies for reclaimed land.

• Horticultural Science & Technology
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• v.30 no.1
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• pp.73-78
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• 2012

KC00256, KC00406, KC00462, KC00463, KC00820, and KC00821, the genetic resources that have previously been reported as moderately resistant to Phytophthora capsici, as well as the line KC01322, a new source of moderate resistance introduced from Laos, were tested against two strains (Pc003 and Pc005) of P. capsici. We also determined the nuclear restorer genotypes of these lines, in regards to their interaction with cytoplasmic male sterility, through crossing the resources with cytoplasmic male sterile Punggok-A (Srfrf) and determining the fertility of the $F_1$ hybrids. The studied lines exhibited a low level of resistance to both the strains of P. capsici compared to highly resistant CM334, but their response was fairly consistent for both P. capsici strains. KC00406, KC00462, KC00463, and KC01322 produced stable, male fertile $F_1$ plants indicating that they are restorers with genotype N(S)RfRf. KC00821 produced male sterile $F_1$ plants and was identified as a maintainer with genotype Nrfrf. The $F_1$ plants of the KC00820 cross, however, set a few male fertile flowers in the greenhouse at seedling stage, then became male sterile after being transplanted to the plastic greenhouse soil in May and remained so to the end of the growing season. Therefore, KC00820 is an unstable maintainer with genotype Nrfrf. The moderate resistance exhibited by these genetic resources may be integrated into breeding programs aimed at promoting higher levels resistance via recurrent selection or hybridization.

• Korean Journal of Breeding Science
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• v.41 no.3
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• pp.346-348
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• 2009

A golden double freesia (Freesia hybrida Hort.) "Golden Amor" was developed from a cross 'Golden Crown' and 'White Wing' followed by seedling and line selections at the National Horticultural Research Institute, Rural Development Administration (RDA) in 2005. Growth and flowering characteristic tests were conducted from 2000 to 2005. "Golden Amor" has large double type flower with bright golden color (RHS 12B). It have multiple florets, good flower shape, upright leaves and stalks. The average yield of "Golden Amor" was 6.0 cuttings per plant in greenhouse carried out from 2003 to 2005. It has good production of cormlets, vigorous growth and resistance to Fusarium and virus. "Golden Amor" would be cultured under greenhouse condition in Korea.

• Mycobiology
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• v.42 no.2
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• pp.203-205
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• 2014

In 2010, symptoms of leaf and stem rot were observed on potted plants (Peperomia quadrangularis) in a greenhouse in Yongin, Korea. The causative pathogen was identified as Myrothecium roridum based on morphological data, internal transcribed spacer sequence analysis, and pathogenicity test. To our knowledge, this is the first report of M. roridum causing leaf and stem rot disease on P. quadrangularis in Korea and elsewhere worldwide.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.5
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• pp.125-134
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• 2018

Recently, interest in alternative energy has been increasing to reduce greenhouse gas emissions and fossil fuel consumption in accordance with the United Nations Framework Convention on Climate Change(UNFCCC). Accordingly, there is a need to use waste heat that unused throughout industrial systems for lowering the concentration of energy on fossil fuels. In particular, government support projects for the energy recycling of agriculture and fisheries such as cultivation of tropical crops and aquaculture are being actively carried out by utilizing waste heat and thermal effluents caused from large-scale industrial complexes including power plants. The study was conducted on supplier (power plant), consumer (farmer) and stakeholders (constructor and local governments) of domestic demonstration areas using waste heat that is abandoned from the power plant in the form of thermal effluents. It investigated the overall improvement and feasibility of government funded projects through field interviews and questionnaire-type surveys. The results of this study are expected to provide basic directions for the operation of the project in terms of nationwide expansion and diffusion of the heat source supply project at horticultural greenhouse by utilizing the thermal effluents from power plant.