• Korean Journal of Weed Science
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• v.5 no.1
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• pp.35-42
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• 1985

This study was carried out to investigate the effect of environmental factors affecting emergence and control of Sagittaria pygmaea Miquel in greenhouse. Emergence of S. pygmaea delayed as the amount of rice straw increased. When the tuber was sowned at 5 to 7㎝ soil depth the emergence of S. pygmaea delayed more in the hard condition of soil than that of the soft condition the large size tuber of S. pygmaea showed less control rate than the small size one at the rate of 2 to 3㎏ prod/10a of butachlor-naproanilide mixtures. The tubers of S. pygmaea seeded at the deeper soil depth decreased weeding efficicy of this mixture. Butachlor-naproanilide mikture showed higher weeding effects at the high temperature and at 2 to 4cm depths of water management than those of the low temperature and at 0cm and 6cm water depths. Weed control rate increased as the rate of butachlor-naproanilide mixture increased. The rate of 4㎏ (prod.)/10a showed good weed effect regardless of application times till 7.5 leaf stage of S. pygmaea. Tuber production of S. pygmea increased as the application time of mixture delayed.

• Journal of agriculture & life science
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• v.45 no.6
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• pp.151-162
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• 2011

Methanol and hexane extracts from 35 species in 27 families of herbal plants were evaluated for their acaricidal activities against two-spotted spider mite, Tetranychus urticae by leaf-dipping and spraying methods in laboratory, pot and field, respectively. Acaricidal activities were different depending on herbal plants. When T. urticae was released on leaves of Phaseolus vulgaris var. humilis that were dipped in the 1,000 ppm hexane extracts from fruits of Torreya nucifer and Daphan genkwa, seeds of Xanthium strumarium and Pharbitis nil at one minute they experienced 56.8, 47.8, 47.7, and 47.7% mortalities, respectively. Dipping time influenced acaricidal activity, that is, one minute dipping was more effective than 30 second dipping of Phaseolus vulgaris var. humilis leaves. However, extracts of X. strumarium and P. nil seeds had comparatively high activities. Concentration of hexane extract of X. strumarium and P. nil seeds revealing LC50 were 1,824 and 1,899 ppm, respectively. Extracts of both plants from hot and cold water were not effective representing <20% mortality at 1,000 ppm. However, hexane extracts of X. strumarium and P. nil seeds were effective against T. urticae on P. vulgaris var. humilis representing 76.3 and 71.3% mortalities in pot, respectively. Control effects of hexane extract of P. nil seed were 50.8 and 35.1% at 2,000 and 1,000 ppm against T. urticae on Chrysanthemum morifolium in greenhouse, respectively.

• Journal of Climate Change Research
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• v.8 no.1
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• pp.21-30
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• 2017

Recently, There has been much discussed about unused space. This space can be used in a variety of ways. Utilizing it as a facility, craft shop, and utilizing renewable energy generation facilities. Especially, in terms of climate change should be supplied renewable energy. Renewable energy needs to be developed in terms of responding to climate change, and the recent Paris agreement is also emphasizing the importance of renewable energy. In particular, renewable energy needs to be widely disseminated. And renewable energy is limited space. In this regard, idle land can provide opportunities for securing new renewable energy generation facilities. The introduction of new and renewable energy facilities in idle space can enhance the self-sufficiency rate of the local community, which is significant in terms of responding to climate. In this study, to investigate the possibility of utilizing a unused space for a photovoltaic power generation facility, we investigated the amount of electricity which could be generated through photovoltaic power generation, and the economic effects, using a RETScreen model. The results showed that 9,738 MWh of power can be generated and that $4,540tCO_2eqcan$ be saved. Regarding the economic effect, the net present value of the facility was shown to be 2,247,389,020 KRW. As the net present value was shown to be positive, we believe that the installation of a photovoltaic power generation facility in an unused space would have a positive economic effect. We found the net present value following the fluctuation of the SMP price to be positive, though there was some variation. However, as the economic efficiency was shown to be low because the net present value in relation to the maintenance costs was negative, we believe that maintenance costs must be taken fully into account when evaluating economic efficiency. In particular, as subsidies can be used to cover maintenance costs which must be factored into photovoltaic power generation, we believe that photovoltaic power generation can have an economic effect. Because spaces not currently in use can have a positive economic effect as renewable energy power generation facilities, and can also contribute to the reduction of greenhouse gas emissions, unused spaces are thought to greatly help local governments to cope with climate change as well as reinforcing their related capabilities. We believe our study will help local governments with decisions relating to unused real estate utilization in the future.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.185-185
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• 2019

Sustaining future wheat production is challenged by anthropogenically forced climate warming and drying led by increased concentration of greenhouse gases all around the globe. Warming stresses, originating from the elevated $CO_2$ concentration, are continuously reported to have negative impacts on wheat growth and yield. Yet, elevated $CO_2$ concentration, despite being disparagingly blamed for promoting warming, is also associated with a phenomenon called $CO_2$ enrichment; in which wheat yield can improve due to the enhanced photosynthesis rates and less water loss through transpiration. The conflicting nature of climate warming and $CO_2$ enrichment and their interplay can have specific implications under different environments. It is established form the field and simulation studies that the two contrasting phenomena would act severely in their own respect under arid and semi-arid environments. Wheat is a dietary staple for masses in Pakistan. The country's wheat production system is under constant stress to produce more from irrigated agricultural lands, primarily lying under arid to semi-arid environments, to meet the rapidly growing domestic needs. This work comprehensively examines the warming impacts over wheat yield and water productivity (WP), with and without the inclusion of $CO_2$ enrichment, under semi-arid environment of Punjab which is the largest agricultural province of Pakistan. Future wheat yields and WPs were simulated by FAO developed AquaCrop model v 5.0. The model was run using the bias-correction climate change projections up to 2080 under two representative concentration pathways (RCP) scenarios: 4.5 and 8.5. Wheat yield and WPs decreased without considering the $CO_2$ enrichment effects owing to the elevated irrigation demands and accelerated evapotranspiration rates. The results suggested that $CO_2$ enrichment could help maintain the current yield and WPs levels during the 2030s (2021-2050); however, it might not withhold the negative climate warming impacts during the 2060s (2051-2080). Furthermore, 10 - 20 day backward shift in sowing dates could also help ease the constraints imposed by climate warming over wheat yields and WPs. Although, $CO_2$ enrichment showed promises to counteract the adverse climate warming impacts but the interactions between climate warming and $CO_2$ concentrations were quite uncertain and required further examination.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.4
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• pp.405-411
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• 1999

Growth responses and yields of cucumber, the populations of soil microorganisms, and the control value of nematodes were examined with six different treatments of chemical fertilizer, compost, microbial fertilizer(MF), and the combined applications of NPK + MF and compost. Cucumber, Eunseong Bakdadaki cultivar, was cultivated in the greenhouse. Higher plant height was appeared with treatments of the combined application of NPK + compost and NPK + MF compared to other treatments, especially at the early growth until 20th day after transplanting. Also, higher number of opened flowers showed with the combined treatments of NPK + compost and NPK + MF than those with others. The control value of nematodes at 60th day after transplanting with treatments of MF and NPK + MF was about 39.0% and 61.6%, respectively. The density of soil microorganisms was higher in order of actinomycetes, bacteria, and fungus. Their densities were not clearly different with treatments. Fruit yields of cucumber with treatments of NPK, compost, microbial fertilizer, and additions of compost and microbial fertilizer to NPk were higher, about 40 to 60%, than that with the control. The highest fruit yield was with NPK + MF and next highest fruit yield was with NPK + compost. It is assumed that the combined application of chemical fertilizers, compost, and microbial fertilizers would be increased the plant productivity.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.4
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• pp.141-150
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• 2022

To abate the environmental burden derived from the massive generation of cattle manure (CM), pyrolysis of CM was suggested as one of the methods for manure treatment. In respect of carbon utilization, pyrolysis has an advantage in that it can produce usable carbon-based chemicals. This study was conducted to investigate a syngas production from pyrolysis of CM in CO₂ condition. In addition, mechanistic functionality of CO₂ in CM pyrolysis was investigated. It was found that the formation of CO was enhanced at ≥ 600 ℃ in CO2 environment, which was attribute to the homogeneous reactions between CO₂ and volatile matters (VMs). To expedite reaction kinetics for syngas production during CM pyrolysis, Catalytic pyrolysis was carried out using Co/SiO2 as a catalyst. The synergistic effects of CO₂ and catalyst accelerate the formation of H₂ and CO at entire temperature range. Thus, this result offers that CO₂ could be a viable option for syngas production with the mitigation of greenhouse gas.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.2
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• pp.77-84
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• 2022

This study aimed to evaluate the growth, yield, and grain quality characteristics of rice varieties that were subjected to water stress during the tillering stage. We also sought to identify whether water stress could be indicated via the plants' response to chlorophyll fluorescence. In this study, we induced water stress by intentionally cutting off water for 30 days, starting 15 days after transplanting the rice varieties to a greenhouse. We analyzed nine rice varieties, including Ilpum, which is the most frequently cultivated variety in Gyeongsangbuk-do, South Korea. The control group was planted in a paddy field where irrigation was entirely dependent on rainfall. Our results revealed that the heading stage of the nine studied varieties occurred approximately ten days earlier in the rain shelter than in the field. Moreover, the rice yield, head rice rate, and palatability score decreased by 18.6%, 17.1%, and 8.3%, respectively, while protein content increased by 20.2% compared with the control group. The Saenuri and Haimi varieties showed the lowest reduction in yield under the water stress conditions, while the Daebo and Samkwang varieties showed the highest reduction in yield. The chlorophyll fluorescence response after re-irrigation was measured between July 30^th and August 17^th. The ratio of variable fluorescence to maximum chlorophyll fluorescence (F_V/F_M) values failed to recover to their baseline values, resulting in either no change or a reduction in fluorescent response, even after re-irrigation of Daebo and Samkwang varieties. These results can be utilized as empirical data for drought-affected farms to select resistant varieties that can respond to spring drought in the southern plains of Gyeongsangbuk-do.

• Korean Chemical Engineering Research
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• v.60 no.4
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• pp.582-587
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• 2022

Biphasic solvents are attracting attention as energy-reducing solvents for capturing CO₂ from flue gas in combustion process. In this study, considering diethylenetriamine (DETA) and diethylethanolamine (DEEA) mixed solvents, one of the biphasic solvents by blending of two types of amines, the CO₂ absorption rates of DETA and DEEA was measured by wetted wall column. The effects of DETA and DEEA concentrations and operating temperature on the overall mass transfer coefficient were investigated. As a result, the overall mass transfer coefficient was proportional to the DETA concentration. However, in the case of the DEEA concentration, the effect was small and when the concentration was exceeded, the overall mass transfer coefficient decreased. The DETA aqueous solution showed little change in the overall mass transfer coefficient with the operating temperature, whereas the DEEA aqueous solution increased the overall mass transfer coefficient with the operating temperature. As a result of obtaining the observed reaction rate constant under the pseudo-first-order reaction assumption, it was found that the observed reaction rate constant in DETA aqueous solution was proportional to the DETA concentration, but DEEA did not fit the pseudo-first-order reaction assumption.

• Journal of Bio-Environment Control
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• v.32 no.1
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• pp.15-22
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• 2023

Roses are one of the most produced flower species in the world, and cut roses are produced in the greenhouses all year round. Recently, due to the increase in the temperature in the greenhouses in summer, the quality of cut roses is seriously deteriorated, such as shortening the stem length. This study was conducted to investigate the effects of the growing seasons on the qualities of cut roses and also to test the effect of cooling at night in high temperature season on the cut flower qualities of roses. Comparing the qualities and yields of cut roses for each season, the major cut flower qualities such as flower stem length, stem diameter and fresh weight were statistically significantly decreased in roses ('Pink Beauty' and 'Pink Shine') produced in summer. The yields didn't show a statistically significant difference in both cultivars. Investigating the cut flower qualities, the flower stem length increased by 15% for 'Pink Beauty', 11% for 'Ararat', and 12% for 'Pink Shine' when treated with cooling at night in warm season than the untreated control. In addition, when treated with cooling at night in warm season, the fresh weight of all three cultivars increased by 20-30% statistically significantly than conventionally cultivated control. It is expected that cooling at night in warm season will be helpful to improve the cut flower quality deterioration in summer.

• Journal of Practical Agriculture & Fisheries Research
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• v.10 no.1
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• pp.77-90
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• 2008

This study was conducted to investigate the influence of chilling temperature and duration at different seeding stages on yield, fruit characteristics and growth of cucumber in a greenhouse. When 20-day-old cucumber were exposed to 0 and 3℃ for 10 hours, 25 and 30% reduction in the main stem elongation rate and 34 and 37% reduction in total leaf area per plant were observed. The reduction in stem elongation and total leaf area was apparently associated with the increases in chilling duration. Exposure of seedlings to 6℃ failed to causes any significant differences in growth as compared to the unchilled plants. Repeated exposure of seedlings to 3℃ chilling for 10 hours per day increased the chilling injury significantly. The seedlings exposed to low temperature for 3 consecutive days exhibited severe injury as compared to the seedlings exposed to chilling treatment only once or twice. Fruit elongation rate was inhibited by approximately 10%, such as 0.59~2.26cm/day, with chilling of 15 hours at 0℃ as compare to 0.61~2.60cm/day in the non-chilled plants. Chilling treatment at 0~3℃ for 10 hours reduced the percentage of marketable fruits by 25~26%. while it increased the percentage of severely bent fruits significantly. Total fruits yield was reduced by 15~25% in cucumber plants when the chilling treatment was given to 20-day-old seedlings and by 22~37% in 30-day-old seedlings. This shows that, Larger seedlings were more sensitive to chilling. Total yield was also influenced by the duration of chilling. Definitely, at 0℃, 5-hour chilling treatment caused 18% of reduction, 10-hour caused 30%, and 15-hour caused 36%, respectively.