• Journal of Bio-Environment Control
• /
• v.27 no.2
• /
• pp.166-172
• /
• 2018

This study set out to conduct a field survey with smart greenhouse-based farms in seven types to figure out the actual state of smart greenhouses distributed across the nation before selecting a system to implement an optimal greenhouse environment and doing a research on higher productivity based on data related to crop growth, development, and environment. The findings show that the farms were close to an intelligent or advanced smart farm, given the main purposes of leading cases across the smart farm types found in the field. As for the age of farmers, those who were in their forties and sixties accounted for the biggest percentage, but those who were in their fifties or younger ran 21 farms that accounted for approximately 70.0%. The biggest number of farmers had a cultivation career of ten years or less. As for the greenhouse type, the 1-2W type accounted for 50.0%, and the multispan type accounted for 80.0% at 24 farms. As for crops they cultivated, only three farms cultivated flowers with the remaining farms growing only fruit vegetables, of which the tomato and paprika accounted for approximately 63.6%. As for control systems, approximately 77.4% (24 farms) used a domestic control system. As for the control method of a control system, three farms regulated temperature and humidity only with a control panel with the remaining farms adopting a digital control method to combine a panel with a computer. There were total nine environmental factors to measure and control including temperature. While all the surveyed farms measured temperature, the number of farms installing a ventilation or air flow fan or measuring the concentration of carbon dioxide was relatively small. As for a heating system, 46.7% of the farms used an electric boiler. In addition, hot water boilers, heat pumps, and lamp oil boilers were used. As for investment into a control system, there was a difference in the investment scale among the farms from 10 million won to 100 million won. As for difficulties with greenhouse management, the farmers complained about difficulties with using a smart phone and digital control system due to their old age and the utter absence of education and materials about smart greenhouse management. Those difficulties were followed by high fees paid to a consultant and system malfunction in the order.

• Journal of Bio-Environment Control
• /
• v.30 no.4
• /
• pp.419-428
• /
• 2021

In order to develope a mobile-based greenhouse energy calculation program, firstly, the overall thermal transmittance of 10 types of major covers and 16 types of insulation materials were measured. In addition, to estimate the overall thermal transmittance when the cover and insulation materials were installed in double or triple layers, 24 combinations of double installations and 59 combinations of triple installations were measured using the hotbox. Also, the overall thermal transmittance value for a single material and the thermal resistance value were used to calculate the overall thermal transmittance value at the time of multi-layer installation of covering and insulating materials, and the linear regression equation was derived to correct the error with the measured values. As a result of developing the model for estimating thermal transmittance when installing multiple layers of coverings and insulating materials based on the value of overall thermal transmittance of a single-material, the model evaluation index was 0.90 (good when it is 0.5 or more), indicating that the estimated value was very close to the actual value. In addition, as a result of the on-site test, it was evaluated that the estimated heat saving rate was smaller than the actual value with a relative error of 2%. Based on these results, a mobile-based greenhouse energy calculation program was developed that was implemented as an HTML5 standard web-based mobile web application and was designed to work with various mobile device and PC browsers with N-Screen support. It had functions to provides the overall thermal transmittance(heating load coefficient) for each combination of greenhouse coverings and thermal insulation materials and to evaluate the energy consumption during a specific period of the target greenhouse. It was estimated that an energy-saving greenhouse design would be possible with the optimal selection of coverings and insulation materials according to the region and shape of the greenhouse.

• Korean Journal of Plant Resources
• /
• v.26 no.6
• /
• pp.701-708
• /
• 2013

To test the quality change of seedlings of three domestic medicinal plants raised in plug trays, a short term storage experiment was conducted. Seedlings were kept in growth chambers for two weeks at 4 or $8^{\circ}C$ temperature combined with 0 or $5{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD. Quality of glasshouse-raised seedlings was assessed after two weeks of cold storage in the growth chamber and one week of acclimation in the greenhouse. After two weeks of storage in the growth chamber of Perilla frutescens var. acuta Kudo, plant height was the greatest in the treatment $8^{\circ}C$ combined with $0{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD. Internode length of P. frutescens var. acuta Kudo was the greatest in the treatment of $4^{\circ}C$ combined with $0{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD. After one week of acclimatization in a glasshouse, the growth and development, such as plant height, internode length and leaf size, were greater in the $8^{\circ}C$ combined with $5{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD than in the other treatments. After two weeks of storage in the growth chamber of Sophora tonkinensis, plant height increased more in the treatment of $4^{\circ}C$ than $8^{\circ}C$. After one week of acclimatization in a glasshouse, number of leaves did not change in the treatment of $4^{\circ}C$ combined with $0{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD, but it increased in the other treatments. Leaf width increased more under the dark than light condition. Leaf length did not observably change in any treatments. After two weeks of storage in the growth chamber, plant height of Angelica gigas Nakai was the greatest in the treatment of $8^{\circ}C$. Number of leaves was the greatest in the treatment of $8^{\circ}C$. Leaf growth was greater under dark than light condition. These results suggested that optimal storage environment was $8^{\circ}C$ combined with $5{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD for P. frutescens var. acuta Kudo, and $4^{\circ}C$ combined with $0{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD for S. tonkinensis and A. gigas Nakai. Hence, proper combination of temperature and PPFD were necessary for better storage, and acclimatization and growth, thereafter, of the plug seedlings of theses plant species.

• Horticultural Science & Technology
• /
• v.19 no.3
• /
• pp.342-347
• /
• 2001

The experiment was carried out to examine the effect of culture media and seawater on growth and mineral concentrations in Glasswort (Salicornia herbacea). Glassworts were grown in a greenhouse with 0, 10, 30 and 90% seawater and with or without nutrient media. The salinity tolerance affected on shoot height and Na, K and Ca concentrations significantly. The shoot height was increased with 10 and 30% seawater concentrations. At the higher seawater concentrations, more Na accumulated in a shoot was obserbed. The application of seawater concentration was effective on increasing Na, Mg, and Fe, concentrations and green leaf area rate and on decreasing K concentration. K/Na ratio of shoot was decreased at high seawater concentration, whereas Na concentrations was lowered at a low seawater concentrations. The mineral concentrations were changed according to the growing season. Na, K and Mg were high in June and Ca and P in September, respectively.

• Horticultural Science & Technology
• /
• v.31 no.2
• /
• pp.141-145
• /
• 2013

The aim of this study was to investigate the effect of two male cultivars of asparagus with low different chilling periods on bud breaking, relative spear growth rate, shoot number and yield. Four-month-old plants of two male cultivars of asparagus were dried to impose dormancy and placed in a coldroom at $5^{\circ}C$ to satisfy the chilling requirement for 0, 2, 4, and 6 weeks. After the specified chilling time, the pots were placed in greenhouse. The results showed that mean days to bud break of 'Jersey Giant' significantly decreased with an increasing chilling period from 0 to 6 weeks, but 'Jersey Supreme' was not affected. The relative spear growth rate of 'Jersey Supreme' was significantly stimulated by chilling compared to non-chilled plants. Shoot production and total spear weight of 'Jersey Supreme' tended to be greater than 'Jersey Giant' irrespective of chilling treatments. Following low temperature treatment, 'Jersey Supreme' showed shorter dormant period than 'Jersey Giant', faster growth of spear. The present study showed that asparagus male cultivar at duration of chilling treatment had an affirmative effect on bud breaking, spear growth rates, shoot number and yield of asparagus.

• Journal of Plant Biotechnology
• /
• v.30 no.1
• /
• pp.47-52
• /
• 2003

Anthers from several lines of carrot (Daucus carota L.) were plated on the semi-solid B$_{5}$, basal medium supplemented with 2,4-D and NAA at two concentrations, 1.0 and 2.0 mg/L plus 0.2 mg/L BAP (benzylaminop-urine). Anthers of the most lines on the B$_{5}$ basal medium with 2,4-D showed higher percentages of callus formation than those with NAA. Particularly, in line 45477, highest percentages of callus formation (50%) were observed on B$_{5}$ medium with 1.0 mg/L 2,4-D plus 0.2 mg/L BAP. With 1.0 mg/L 2,4-D, two months was sufficient for initiation of callus development. Calli were regenerated into plantlets through embryogenesis onto regeneration medium without any growth regulators. When callus showing yellowish and soft structure was cultured, it yielded green plants at high regeneration rates, The response of anthers in callus induction and plant regeneration was different among lines investigated. Optimal callus induction and plant regeneration could be obtained through manipulating the concentration of growth regulators. Plantlets after transfer to perlite were grown successfully in greenhouse conditions. Anther culture of carrot will be used as a useful breeding tool in future.

• Horticultural Science & Technology
• /
• v.18 no.4
• /
• pp.529-535
• /
• 2000

Organic materials such as composted rice-hull, saw dust, and pine bark, and inorganic materials such as vermiculite, perlite, and recycled rockwool were commonly employed as container media in domestic greenhouse industry. The objective of this research was to get informations in soil physico chemical properties of those materials. Composted dry-peeling bark and wet-peeling bark had 72.1% and 69.1%, respectively, in particles larger than 1.0 mm, which were much higher than 34.7% of composted rice-hull and 33.7% of composted saw dust. Imported vermiculite had 89.9%, but domestic vermiculite had 25.7% in particles larger than 1 mm. In soil physical properties, Russian peat had the highest container capacity of 79.3%, and wet-peeling bark had the lowest container capacity of 58.2%. However, Russian peat and composted saw-dust had 4.1% in air space indicating that possible problems could occur in soil aeration when those are employed for container grown crops. Saw dust had $2.3mS{\cdot}cm^{-1}$ in electrical conductivity, while other composted organic materials had less than $0.25mS{\cdot}cm^{-1}$. Imported vermiculite had 64.0 meq/100 g in cation exchange capacity, which was 2.4 times higher than those of domestic vermiculite, 27.2 meq/100 g. Domestic vermiculite had higher Ca and Mg and less Na contents than those of imported vermiculite.

• Korean Journal of Agricultural Science
• /
• v.39 no.4
• /
• pp.515-523
• /
• 2012

Recent development and enlargement of reclaimed lands along the sea shores required to explore alternatives to existing crops, which are suitable to grow well and to declare higher profits. The objectives of this study were to investigate yield-related parameters for development of new leafy vegetables, and to screen some candidates among New Zealand spinach genotypes which were collected in Korea. Initially all the collected genotypes were grown for 7 weeks in a greenhouse of the experiment field in Chungnam National University, and then transplanted into the field to measure morphological or physiological parameters (plant height, branch number, stem diameter, chlorophyll content, and maximum canopy diameter), and yield-related parameters (leaf number, leaf length, leaf width, fresh weight and dry weight). Those parameters were quantitatively measured at 1, 5 or 9 weeks after transplanting (WAT). Parameters exhibiting statistically significant difference among the accessions were plant height, branch number, maximum canopy diameter, chlorophyll content, and leaf length. In contrast to highly correlated parameters with fresh and dry weight obtained in salt-affected soil in the earlier report, fresh weight was correlated significantly with leaf length (r=0.72), leaf width (r=0.64), and canopy diameter(r=0.66), while dry weight was correlated significantly with plant height (r=0.46), leaf length (r=0.72), leaf width (r=0.73), fresh weight (r=0.79), chlorophyll content (r=0.47), and canopy diameter (r=0.87). Based on the significantly correlated with yield parameters, the candidate accessions which were ranked in top statistical groups include CNU06A01, CNU06A13, CNU06A26, CNU06A35, CNU06A38, and CNU06A55. In order to be cultivated in reclaimed lands, it is necessary to screen out salt tolerant accessions among the above high-yielding genotypes.

• Journal of Bio-Environment Control
• /
• v.21 no.4
• /
• pp.404-410
• /
• 2012

This study was conducted to examine effects of harvest time (09:00 vs. 14:00), precooling at $4^{\circ}C$ vs. no precooling, and storage temperature (4 vs. $8^{\circ}C$) on the storage life of 'Maehyang' strawberry fruits for export. Fruits at a 60% ripe stage were harvested from a commercial greenhouse in Gyeongsangnamdo, Jinju on May 4, 2010. Fruits were precooled by a forced draft cooling for three hours, transported for about 30 minutes and then stored, immediately. Small precoolers set in the farm were used for precooling. Fruits were placed in constant temperature chamber (4 or $8^{\circ}C$) after packaging using PVC wrap and a cardboard box. Fruits were examined for their changes in weight, hardness, Hunter color values, soluble solids content (SSC), and incidence of gray mold (Botrytis cinerea) during storage at a two days interval from May 6 to May 14, 2010. Hardness and SSC decreased as the ripening stage progressed. The Hunter's 'L' and 'a' value of fruit color decreased as time passed. Also, fresh weight decreased during storage at all temperatures. Soft rot appeared on epidermal tissues and followed by gray mold. Incidence of gray mold was greater at $8^{\circ}C$ storage temperature than in $4^{\circ}C$ storage temperature. However, no difference by the harvested time and precooling. The results indicate that effectiveness for keeping the freshness was best achieved by precooling at $4^{\circ}C$ and storage at $4^{\circ}C$, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.10
• /
• pp.6114-6125
• /
• 2014

This paper analyzed the issues related to focus on farmers behaviors of energy saving facilities. This study conducted questionnaire and field surveys of controlled horticulture farmers and economic analysis using an IPA(Importance-Performance Analysis) matrix. According to the research results, the performance level was low on average ranging from 2.33 to 2.56 in a five point Likert-scale on greenhouse mandarin and grape-related facilities. On the other hand, the importance levels were high in the mean rating from 2.69 to 4.8. The results show that energy loss reduction of complementary facility and alternative energy supply support for low cost implementation are more important in terms of the respondents concerns than performance quadrant III. Therefore, it is important to provide financial support to energy-saving facilities to promote the use of energy efficiency improvement. In addition, the government should invest continuously in research and development.