• Journal of Korean Society of Steel Construction
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• v.23 no.1
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• pp.41-49
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• 2011

A long-span (more than 8m) plastic greenhouse is currently being used in farms due to its magnified benefits, such as the convenience of the farming equipment used, and the land usage efficiency. In this study, the reinforcing effects of the use of a pretension tie were shown. In a previous study, tests for a 6.5m single-span-type greenhouse announced by Rural Development Administration were carried out. The tests of symmetric and eccentrics now loading by the sun and wind were conducted for the 10.2m span with a ${\phi}48.1{\times}2.1$ section in this study, after which the load-deflection relationship was compared for the cases of reinforcement with a tie and without a tie. The results of the symmetric snow loading test showed that the strength increased by 68~93% in the case of the specimen with a tied arch. The failure mode of the specimen without a tie tended to be that with a sway failure mechanism, and that of the reinforcement specimens with a tie tended to be that with an arch buckling mechanism. The results of the eccentric snow loading test showed that the strength of the specimen with a tie increased by 10~20% compared to that of the specimen without a tie. For the failure mode of the latter, a combined failure mechanism was adapted, although the failure mode of the tied specimens tended to be that with an arch buckling mechanism.

• 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.

• Korean Journal of Environmental Agriculture
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• v.2 no.2
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• pp.114-119
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• 1983

Several supplementary heating methods were investigated to find their effects on night air temperature, injury in plant, growth and yield with Hokowase strawberry(Fragaria grandiflora) under greenhouse, during early spring season in 1981 and 1982. Kerosene lamp as a supplementary heating was not suitable because of its severe injury on strawberry plants, danger of accidental fire and bad smell. Paraffine candle and electric wire heating did not injure on strawberry plant, raised the minimum air temperature in greenhouse at night, enhanced growth, flowering and harvesting time of strawberry. Paraffine candle was effective as a supplementary heating method for short period growing under greenhouse, whereas electric wire heating was suitable for long period cultivation.

• Environmental and Resource Economics Review
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• v.18 no.4
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• pp.587-635
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• 2009

The purpose of this study is to develop the Global Dynamic Computable General Equilibrium Model (Global CGE Model) in order to produce an economic impact analysis, including prospective obligations for the Post-2012 regime. This model explores the impact of an international emissions trading market and macroeconomic variables such as GNP, consumption, investment, imports and exports, in accordance with potential increased obligations on the Republic of Korea. Distinguishing it from existing studies, this Global CGE Model divides the global community into major economic groups, and in the capacity of the analyzed global model, reflecting the principle nations' macroeconomic indicators through the theoretical approach of endogenous growth theory. Policies such as an emissions trading scheme and carbon tax are reflected in the model. Also, in particular, the model reflects exogenous technological advances. According to this analysis, the stronger the greenhouse gas reductions, the greater the adverse effects on the economy; among macroeconomic indicators that appear, a significant decline is realized in the balance of trade, along with a significant decrease in investment and consumption. Energy dependence, in particular, plays a large role-varying in degree by industry type-, as greenhouse gas reductions would have a greater impact on energy-intensive industries. Furthermore, if Korea, currently recognized as a developing country, is given the obligation to reduce greenhouse gas emissions, competing countries such as China and other developing countries will be given an advantage.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.6
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• pp.127-135
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• 2017

In this study, a cold well and a warm one with the distance of 100 m were installed in the alluvial aquifer. Groundwater used as the heat and the cold source of heat pump was designed to flow into the warm and the cold well with a diameter of 200 mm. In order to increase the heat and cold storage in aquifer, six auxiliary wells with the diameter of 50 mm and the depth of 30 m were installed at an interval of 5 m from the main well. Also, heat pump 50 RT, the thermal tank $40m^3$, and a remote control and monitoring system were installed in three single-span greenhouses ($2,100m^2$) for growing tomato in Buyeo, Chungcheongnam-do. According to the aquifer heat storage test which had been conducted from Aug. 31 to Sep. 22, 2016, warm water of $850m^3$ was found to flow into warm well. The temperature of the injected water was $30^{\circ}C$ (intake temperature : $15^{\circ}C$), and the heat of 12.8 Gcal was stored. The greenhouse heating test in winter had been conducted from Nov. 21, 2016 to Apr. 30, 2017. On Nov. 21, 2016 when heating greenhouse started, the aquifer temperature of the warm well was $18.5^{\circ}C$. The COP for heating with water source at $18.5^{\circ}C$ was 3.8. The intake water temperature of warm well was gradually lowered to the temperature of $15^{\circ}C$ on Jan. 2, 2017 and the heat pump COP was measured to be 3.2 at that time. As a result, the heat pump COP was improved by 18 %. and retrieval heat was 8 Gcal, the retrieval rate of heat stored in aquifer was estimated at 63 %.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.665-672
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• 2013

This study was conducted to evaluate the effects of a chelating agent on cucumber growth and changes in soil nutrients availability in polytunnel greenhouse fields. Diethylene triamine penta acetic acid (DTPA) was selected as a chelating agent. Two experiments were carried out as follows: i) For field experiment in the autumn season of 2010, each plot was treated by varying the concentration and the number of times being applied with DTPA; [DTPA (0.5 mM, 1 time/3 months), DTPA (0.06 mM, 1 time/1 week), DTPA (0.13 mM, 1 time/2 weeks), DTPA (0.06 mM, 1 time/1 week)+N]. Conventional practice was also investigated. ii) In the spring and summer seasons of 2011, each plot was treated by varying the concentration (0, 0.06, 0.13, 0.19 mM) of DTPA, chemical fertilizers (NPK), and combination of chemical fertilizers and DTPA 0.06 mM. The fruit yields of cucumber and soil chemical properties had no significant differences between treatments. However, in the spring season of 2011, DTPA 0.06 mM plot added 1 time per 2 weeks increased the yield of cucumber, but caused the reduction of yield in next cultivation season. This result showed that excess use of DTPA can cause the damage of crop growth. The inorgainc contents such as Ca and Mg absorbed by cucumber plant had significant differences between DTPA 0.19 mM (2 times/1 week) and fertilizers plus DTPA treatments [DTPA 0.06 mM (2 times/1 week) + 1/2 NPK, DTPA 0.06 mM (2 times/1 week) + NPK]. The input cost of fertilizers was saved when the concentration and the number of times added with DTPA was 0.06 mM and 1 time a week, respectively. This treatment used 67% less of applied fertilizers cost than the plot of conventional practice did. Thus, this research suggested that the application of DTPA 0.06 mM by 1 time a week can be effective for sustainability of crop production and reduction of fertilizers usage in polytunnel greenhouse.

• Korean Journal of Medicinal Crop Science
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• v.24 no.2
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• pp.101-109
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• 2016

Background: The purpose of this study was to evaluate methods to reduce seeding expenses, thereby increasing farm income. This study investigated the effects of rain shelter controlled cultivation and adapted seeding times on the stable seed production of Scutellaria baicalensis Georgi. Methods and Results: Seed germination was conducted under 10 condition compose to control, water washing, cold storage at $4^{\circ}C$ for 15 days, seed sterilization with a benomyl pesticides, hormone treated seed by submerging in 100 ppm $GA_3$ with the cold storage at $20^{\circ}C$ and $25^{\circ}C$, darkness in a covered petridish and illuminated with a 1,500 Lux lamp. There were three cultivation type, open cultivation with non-woven fabric mulching, cultivation with a vinyl covering and rain sheltered in a plastic greenhouse. Sowing dates were April 27, May 18, June 7 and June 28, 2013. Plants were spaced 10 cm apart in rows 30 cm apart. Mixed oil cake fertilizer, $N-P_2O_5-K_2O$ (12-10-10) was applied at $600kg{\cdot}10a^{-1}$. Conclusions: Optimum germination occured in darkness at $25^{\circ}C$ and cold storage after submerging in $GA_3$. The highest seed yields ($4.5kg{\cdot}10a^{-1}$) occurred in the plastic greenhouse for the April 25 sowing. The highest root yield (17%) was found on April 1, under greenhouse conditions.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.53-53
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• 2022

Modem agricultural production needs to provide sustainable management practices that are eco-friendly and low cost. Plant extracts are a cost-effective and environmentally friendly alternative to synthetic plant growth regulators. This study was therefore carried out to investigate the effects of various plant extracts produced using different extraction methods on the vegetative growth of rice under laboratory and greenhouse conditions. For this study, seventeen plant extracts were made from plant species such as leaves of M. arvense, C. asiatica, M. oleifera, V. radiata, V. unguiculate, P. guajava, A. vera, and A. tuberosum, aboveground plant parts of C. rotundus, M. sativa, and P. frutescens, roots of R. undulatum, tubers of A. sativum, leaves and stems of G. max (cv. Taegwang) as well as rice straw and hulls (cv. Hopyeong). As a test crop, we applied these extracts to rice plants. For the purpose of making our extracts, some plant materials and species were collected in fields and others were purchased from Chonnam Hanyaknonghyup Cooperation (South Korea). Leaves, roots, and aboveground plant parts of plant species were dried, ground, extracted (water, boiling water and ethanol) and fermented. Rice growth promotion effects were determined using plant extracts at 0, 0.05, 0.1, 0.5, and 1% concentrations under petri dish conditions. Seven selected plant extracts were applied to rice seeds with soil drench application or seedling at 3-4 leaf stages with soil and foliar applications under greenhouse conditions. For comparison with extracts, we used urea at 0.6%. Of the 17 water extracts used in this study, 10 extracts reduced rice growth, but the other 7 extracts (P. guajava, A. vera, A. tuberosum, M. sativa, A. sativum, and G. max) increased growth by 40-60% on compared to the control in Petri dish bioassay. Thus, these 7 extracts were selected for further study. Under greenhouse conditions, rice growth also increased by 20-40% when the same 7 extracts were applied to rice seeds using soil drench application. Furthermore, at the 3-4 leaf stage rice growth also increased 30-80% or 30-60% when the same 7 extracts were applied using soil and foliar applications. Overall, the 7 extracts produced higher rates of growth promotion when soil drench application was used than when foliar application was used. In the case of boiling water and ethanol extracts, rice growth increased only 20% in response to both soil drench and foliar application of the same 7 extracts. Rice growth promotion was greater when extracts were produced using water extraction method than boiling water and ethanol extraction methods. Most notably, the 7 water extracts used in this study produced higher rates of growth promotion than urea at 0.6% which is typically used for crop growth promotion. Overall, the 7 water extracts when applied using soil drenching method can be used as effective growth promotors of rice in organic agriculture.

• Korean Journal of Organic Agriculture
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• v.32 no.1
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• pp.75-90
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• 2024

Biochar is a solid substance with a high carbon content, as it is made out of biomass pyrolyzed under the condition of limited oxygen. This product has attracted attention as an environment-friendly soil amendment because it contributes to carbon neutrally and has improvement effects on the soil environment. This study conducted an experiment to evaluate soil physiochemical properties and microbial community changes in a melon greenhouse according to the applied amount of biochar to investigate the growth characteristics and yields of melons accordingly. In soil physical properties, an increase in the applied amount of biochar resulted in a decrease in bulk density and an increase in porosity of the soil, improving air permeability. In soil chemical properties, an increase in the applied amount of biochar led to a increasing of pH, organic matter and available phosphate content. In the growth characteristics of melons, there was a growing tendency of plant height, leaf length and leaf width according to the increasing application of biochar until 10,000 kg/ha. Moreover, melon yields also increased as the amount of biochar, 13~16% higher in 10,000 kg/ha biochar application than no treatment. Compared differences among microbial communities in the soil according to the application of biochar and found that plant beneficial bacteria dominated in biochar treatments. This study demonstrated the potential of biochar as an effective soil amendment in melon greenhouse by showing improvements in soil physicochemical properties and microbial communities.

• Journal of the Korean Society of Safety
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• v.28 no.5
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• pp.66-70
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• 2013

This study examined the relative effects of education and eco-IVIS(in-vehicle information system) to reduce fuel consumption and greenhouse gas emissions. Also the study investigated the increasing of driving workload when drivers interact with intervention technique. Thirty participants randomly assigned into two groups(training and eco-IVIS) and conducted driving before and after the each intervention technique. While driving, we observed three driving behaviors: Frequency of excessive RPM, percent of speeding, and mean fuel efficiency. Also the Driver Activity Load Index was used to rate participants' subjective ratings of driving workload. Although the results showed positive impact of both education and eco-IVIS to increasing the eco-driving behaviors, eco-IVIS was more effective than education. However, we found comparable level of driving workload in the education and eco-IVIS.