• Horticultural Science & Technology
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• v.35 no.4
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• pp.418-430
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• 2017

The objective of this study was to understand the combined effect of shading treatment and harvest time on pungency, ascorbic acid content, market-quality pepper yield, and photosynthetic activity in a yellow 'Star Flame' and 'Fire Flame' F1 hybrid pepper cultivar (Capsicum annuum). Plants were cultivated in a greenhouse under white, red, and green shading nets and compared to those grown under unshaded control conditions. The ascorbic acid and pungency parameters were analyzed by high-performance liquid chromatographic methods. Ascorbic acid, a compound of high nutritive value in pepper, was highest in fruits gathered during the first summer harvest in both hybrids. The ascorbic acid content was found to be further increased in fruits from plants grown under white net shading in both 'Star Flame' and 'Fire Flame'. Total capsaicinoid contents in 'Star Flame' were influenced by the interaction of shading treatment and harvest time (p = 0.004), with the lowest amounts ($241.2-251.5mg{\cdot}kg^{-1}$ fresh weight) resulting from white and red shading treatments at the early autumn harvest. In 'Fire Flame', both shading treatment (p = 0.009) and harvest time (p < 0.001) affected total capsaicinoid contents. We observed significantly higher total capsaicinoid contents in control fruits compared to that resulting from red and green shading treatments at the second harvest, and that resulting from red shading treatment at the third harvest. Analysis of photosynthetic activity revealed a significant and negative correlation between Fv/Fm values and total capsaicinoid contents in both hybrids (p < 0.001). Based on the obtained results, the harvest of peppers during summer should be promoted to produce fruits with high pungency.

• Horticultural Science & Technology
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• v.29 no.1
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• pp.77-80
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• 2011

A new bi-color mini gerbera (Gerbera hybrida Hort.) 'Sun Cap' was developed from a cross of '99-ga-2' and '99-na-3-1' followed by seedling and line selections at the Flower Research Institute, Gyeongnam Agricultural Research and Extension Services (ARES) in 2007. Characteristic tests were conducted three times from 2004 to 2007. 'Sun Cap' has single type in good harmony with bi-color (Red/Yellow, RHS 45-B/9-A) ray floret and green center. It has good stable flower shape and strong peduncle. Its vase life was 13.5 days. The average yield of 'Sun Cap' was 102.6 flowers per plant a year in greenhouse. Yield trials were carried out from 2004 to 2007. This cultivar was registered for commercialization in 2009. 'Sun Cap' would be cultured under greenhouse condition in Korea.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.328-334
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• 2013

A greenhouse heating system to improve heat pump performance using inside and outside air of greenhouse as a heat source selectively and cut $CO_2$ enrichment costs by delay of greenhouse ventilation was developed. In this system, thermal storage modes divided into inside circulation mode using surplus solar energy and outside circulation mode using outside air heat. The thermal storage modes were designed to be switched mutually according to inside greenhouse temperature and six temperature values were input to control the heat pump operating, thermal storage mode switching and greenhouse heating automatically. Operating characteristics of this system were tested in a plastic greenhouse of non-ventilation condition. The results of test showed that the inside circulation mode began at about 11:00 and lasted for about 210 minutes and inside greenhouse temperature was maintained between $20{\sim}28^{\circ}C$ in spite of non-ventilation. System heating COP of the inside circulation mode in the daytime was 3.35, which was 36% and 25% higher than that of the outside circulation modes in the nighttime and daytime respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.610-615
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• 2010

This study was conducted to evaluate fertigation effects of pig slurry (PS) and chemical fertilizer (CF) in tomato by analyzing the growth and yield, nutrient content and uptake, nutrient use efficiency, and soil characteristics in greenhouse cultivation. The treatments compared were; no-fertilizer, two different levels of PS (26 mg $L^{-1}$ and 52 mg $L^{-1}$), and a control treatment of chemical fertilizer. There was no significant difference in growth and yield between PS and CF treatments. however, yield reduction was observed in PS 26 mg $L^{-1}$ treatment. The N-utilization efficiency in CF treatment was similar to that of PS 52 mg $L^{-1}$ treatment. Nutrient utilization efficiency decreased in order of potassium (K), nitrogen (N), phosphate (P) with 29.2~43.3% in K, 15.8~36.7% in N, and 3.0~6.3% in P. In soil chemical characteristics, soil pH in PS treatment was higher than in CF treatment. In contrast, nitrate content in soil was higher in CF treatment than in PS treatment. The content of exchangeable K in soil was higher in PS and CF 52 mg $L^{-1}$ treatments. There was no significant difference in exchangeable Ca and Mg among those treatments. Therefore, it can be concluded that chemical fertilizers can be substituted by PS based on soil chemical analysis in tomato fertigation culture.

• Journal of Digital Contents Society
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• v.19 no.4
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• pp.749-756
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• 2018

In this study, we developed a prediction model for greenhouse control using machine learning technique. The prediction model was developed using measured data (2016) on greenhouse in the Protected Horticulture Research Institute. In order to improve the predictive performance of model and to ensure the reliability of data, the dimension of the data was reduced by correlation analysis. The dataset were divided into spring, summer, autumn, and winter considering the seasonal characteristics. An artificial neural network, recurrent neural network, and multiple regression model were constructed as a machine leaning based prediction model and evaluated by comparative analysis with real dataset. As a result, ANN showed good performance in selected dataset, while MRM showed good performance in full dataset.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.688-692
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• 2005

Importance of substitute energy has been increasing due to environmental issues and lack of fossil fuels. In addition, heating cost that occupies from 30 to $40\%$ of the total production cost in Korean protected cultivation needs to be reduced for profitability and global competition. But, studying on substitute energy to solve these problems has not been activated for Korean protected cultivation. Therefore, this study was conducted to develop a geothermal heat pump system for cool ing and heat ing of greenhouses at a lower cost than conventional hot air heater and air conditioner. Fundamental test of heat transfer characteristics in soil was conducted by computer simulation and controlled tests for its verification. Based on the results of the theoretical and empirical investigations, an optimum heat pump system was developed and the performance was evaluated for practical use in a greenhouse at the Pusan Horticultural Experiment Station. The system was compared with a conventional hot air heating system through a cucumber growing test and economic feasibility analysis. Results of the application test of the geothermal heat pump showed that with an initial setting of $15^{\circ}C$ the inside temperature of the greenhouse could be maintained between 15 and $17^{\circ}C$. Results of the cucumber growing test showed that there were no significant differences in average height, leaf length, leaf width, number of nods, leaf area, dry weight and yield between the plots wi th the geothermal heat pump system and a conventional hot air heater. Economic feasibility analysis indicated that the variable cost of the hot air heater could be saved $81.2\%$ using the geothermal heat pump system. It was concluded that the geothermal heat pump system might be a pertinent heating and cooling system for greenhouses because of the low operating cost and the use of environment-friendly geothermal energy.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.3
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• pp.218-224
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• 2015

Zeolite may help crop growth, yield increase, and salt removal. Field experiment under greenhouse cultivation was conducted to study the effect of zeolite application on growth and yield of Chinese cabbage (Brassica campestris L.) and soil. Soil was classified as Gyuam series (coarse silty, mixed, nonacid, mesic family of Aquic Fluvaquentic Eutrudepts). Six zeolite rates were 0, 3, 5, 10, 20 and $40Mg\;ha^{-1}$. Experimental design was a completely randomized design. Chinese cabbage was grown three times consecutively. Established plant number of plant and yield as fresh weight (F.W.) were measured and soil samples were taken before and after harvesting. Chinese cabbage yield was $76.9Mg\;ha^{-1}$ at a rate of $20Mg\;zeolite\;ha^{-1}$, $54.3Mg\;ha^{-1}$ at a rate of $5Mg\;zeolite\;ha^{-1}$, and $51.3Mg\;ha^{-1}$ at control (no zeolite), respectively. Second order regression analysis using zeolite rate and yield showed that optimum zeolite application rate was between 24 and $26Mg\;ha^{-1}$. The regression equation explained about 88% of the yield variability. The electrical conductivity (EC) decreased from 3.2 to $1.0dS\;m^{-1}$ for all treatments so that salt accumulation was not a concern. Based on the results, we recommend that optimum zeolite application rate is between 20 and $24Mg\;ha^{-1}$ for Chinese cabbage under greenhouse cultivation.

• Horticultural Science & Technology
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• v.34 no.6
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• pp.845-859
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• 2016

This study was conducted to examine the effect of nighttime ventilation and heating on changes in temperature and humidity, the occurrence of white rust, and growth of standard chrysanthemum (Dendranthema grandiflorum) 'Baekma' in a greenhouse. For the ventilation treatments, the mean nighttime humidity in the control greenhouse, which had a closed side window, was higher (94.5%), but the humidity in the natural and natural+fan ventilation treatments was lower (74.3% and 72.8%, respectively). The rate of occurrence of white rust at 34 days after treatment was 100, 98.3, 75.6, and 43.3% for the control, fan ventilation, natural ventilation, and natural+fan ventilation treatments, respectively. The number of infected leaves and telia were the lowest in the natural+fan ventilation treatment compared with the other treatments. The growth of the chrysanthemum 'Baekma' was significantly suppressed in the control because of the occurrence of white rust and high humidity, while plant height, number of leaves, stem diameter, and fresh weight were the greatest in the natural+fan ventilation treatment. For the heating treatments, the mean nighttime temperature of the control (RH 95% heating), which was heating and held at 95% humidity, was $18.4^{\circ}C$, while the temperature of the heating treatment, which was held at 70% relative humidity (RH 70% heating) was $25.8^{\circ}C$. The rate of occurrence of white rust (34.4%), number of infected leaves (0.9), and telia (1.0) were the lowest in the RH 70% heating treatment compared with the other heating conditions. Also, the RH 70% heating treatment showed the best growth in terms of plant height, stem diameter, number of leaves, and fresh weight. Therefore, the natural+fan ventilation and RH 70% heating treatments were effective for the control of white rust and the growth of standard chrysanthemum 'Baekma' in a greenhouse.

• Korean Journal of Agricultural Science
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• v.40 no.4
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• pp.271-276
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• 2013

This experiment was carried out to determine optimal culture conditions for the production of tubers of Calla (Zantedeschia elliottiana 'Golden Affair' and 'Black Magic') in Korea highland. In vitro produced plantlets and tuberlets of Calla 'Golden Affair' and 'Black Magic' were planted plastic film greenhouse and grown for 100, 120, 140 days, with different night temperature treatments ($0{\sim}10^{\circ}C$ : no heating, 10, $15^{\circ}C$). In both cultivars, tuber size(tuber diameter, tuber height) and tuber weight increased with increasing cultivation period when the night temperature was maintained at $10^{\circ}C$. The largest tuber diameter in vitro produced plantlets was 5.8cm in 'Black Magic' and 3.2cm in 'Golden Affair', and daily tuber growth rate was 1.110g in 'Black Magic' and 0.092g in 'Golden Affair' under the culture conditions. Consequently we think that tuber harvest date was Oct. 30 and night temperature was $10^{\circ}C$ and no heating that was proper method of tuber production. However we had selection of $10^{\circ}C$ treatment for tuber production because it appeared freezing damage occasionally in highland late in October.

• Journal of People, Plants, and Environment
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• v.23 no.3
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• pp.255-265
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• 2020

Background and objective: The purpose of this study was to provide guidelines for irrigation management by analyzing the effects of soil moisture on the growth characteristics of herbaceous plants in green infrastructure. Methods: In a rain shelter greenhouse, the growth performance of nine species of experimental plants was assessed under different soil moisture contents (20%, 15%, 10%, 5%, and 1%) for about 5 months to analyze plant growth characteristics due to soil humidity. Methods to determine plant growth conditions include surveying growth conditions of the crowns, stems, leaves, flowers and fruits on the aerial part and surveying growth conditions of the roots in the underground part. Results: The results showed that Mukdenia rossii and Astilbe rubra grew well at 15% moisture content with irrigation intervals of 10 and 13 days, respectively. Soil moisture content of 10% with irrigation intervals of 13 and 17 days was appropriate for Sedum kamtschaticum and Pachysandra terminalis. Similarly, Aquilegia japonica and Liriope platyphylla grew well at 15% moisture content with irrigation intervals of 10 and 17 days. However, Ligularia stenocephala grew well-developed stems and roots at 1% soil moisture content and an irrigation interval of 25 days, while the optimum conditions for Lythrum anceps were 5% moisture content and an irrigation interval of 8 days. Conclusion: Although a limited number of experimental plants were used in this study, this study could propose an appropriate irrigation cycle for planting on artificial soil substrates. Based on these results, it is possible to plan suitable planting designs considered irrigation cycles.