• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.283-290
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• 2017

In this study, the method to attach plastic film on the side vent from inside of greenhouse for the entire length was developed as the way to make crops less stressful while uniformly getting outside air into the greenhouse when ventilating using roof ventilation fans at single-span plastic greenhouse for oriental melon in a low-temperature period. The plastic film was installed from ground to 10cm below from the height where side vent is fully opened. In order to verify that the improved side vent can improve greenhouse environment and fruit yield, it was compared with the control plot of conventional side vent. Both greenhouses were not ventilated until February 25th, 2017. Air temperature in both greenhouses exceeded $40^{\circ}C$ in mid February. Therefore, it is judged that the greenhouse should be ventilated from mid February. Air temperature in the control plot exceeded $30^{\circ}C$ from late April. Therefore, it is judged that the plastic film attached to the inside of side vent should be removed in late April, or in early May at the latest. Soil temperature in the treatment plot in the mid Aril exceeded $20^{\circ}C$, which is suitable for growth, while that in the control plot was still below $20^{\circ}C$. Soil temperature in the control plot finally exceeded $20^{\circ}C$ in late April. The consumption of electricity was 47.2 kWh in the treatment plot, and 48.3 kWh in the control plot, which was no significant difference. The marketable yield of oriental melon in the treatment plot was 5,094kg, which was 23.9% more than that in the control plot, 4,113kg. The marketable fruit ratio was 73.5% in the treatment plot, and that in the control plot was 73.9%, which was no significant difference.

• Korean Journal of Ecology and Environment
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• v.49 no.2
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• pp.89-101
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• 2016

To elucidate occurrence patterns of $C_4$ plants in agroecosystems, we surveyed flora inside fields and embankments in 222 sites in farming lands in summer and fall, 2013. We also observed Kranz anatomy and analyzed carbon stable isotope to classify photosynthesis types. Our study observed total 54 species of $C_4$ plants in 33 genera and 9 families of vascular plants besides cultivated crops occurring in farming fields. The most common species was Portulaca oleracea L. followed by Digitaria ciliaris and Echinochloa crusgalli (L.) P. Beauv. var. crusgalli among the $C_4$ plants. The ratios of $C_3$ and $C_4$ species number to total number of species tended to maintain constant regardless of survey times and habitat types. The proportion of $C_4$ species to the total number of species were more influenced by the number of $C_3$ species than those of other types in the surveyed sites. Sizes of cultivation areas did not affect the proportions of $C_4$ plants. Increasing number of simultaneous weeding methods, especially with cutting method, appeared to decrease the number of $C_3$ plants. On the other hand, as the number of cultivated crops increased, both $C_3$ and $C_4$ plants increased but the proportions of $C_4$ species remained. We interpret our results that proportion of $C_4$ species in agroecosystems, appear to be dependent on the number of $C_3$ species, which in turn, appear to be affected by cultivation methods.

• Horticultural Science & Technology
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• v.31 no.4
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• pp.457-466
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• 2013

Since the early 1980s, the National Institute of Horticultural & Herbal Sciences has been breeding and collecting diverse radish breeds to select those samples with better horticultural characteristics, to ultimately expand and develop as good radish produce. Genetic diversity is a crucial factor in crop improvement and therefore it is very important to obtain various variations through sample collection. The collected samples were compared with one another in order to assess the level of diversity among the collections, and this procedure allowed for increased application of the gathered resources and aided in determining the direction to secure further samples. Towards this end, this experiment was conducted in order to examine whether the SSR markers derived from Chinese cabbage samples could be transferred to the radish samples. Among the radish breeding lines and introduced resources, 44 lines were used as materials to analyze the genotype using 22 SSR markers selected. As a result, the analysis showed that among all the selected markers, 'cnu_m139' and 'cnu_m289' were the most useful markers for diversity evaluation. The genetic relationship of the radish genetic resources showed that the geographic origins affected the diversity. Furthermore, the different types of radish groups were also determined by the year they were bred. This result demonstrated that there are differences between the older radish breeds and the more recently developed radish breeds. Even though a relatively small number of markers were used in the analysis, it was possible to distinguish whether the radish was bred 30 years ago or in the 2000s, and that the similar physical shapes comprised a particular group, showed that the SSR markers can indeed be successfully applied to to study the diversity within radish breeding lines. Through the results of this study, it can be concluded that the SSR marker developed for the Chinese cabbage can be applied to examine the genetic diversity and analyze the relationship (genetic resource determination) of radish.

• Korean Journal of Ecology and Environment
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• v.47 no.1
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• pp.32-40
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• 2014

This study was conducted to evaluate the growth response of economical six leafy vegetables that are crown daisy, pak-choi and four kinds of lettuce (Red leaf lettuce, Green leaf lettuce, Head lettuce, Romaine lettuce) by light treatment of LED in plant factory. The light treatments were composed of red, blue, red+farred, red+blue, red+blue+white LEDs, irradiation time ratio of the red and blue LED per minute (1 : 1, 2 : 1, 5 : 1, 10 : 1), and duty ratio of mixed light (100%, 99%, 97%). The following results were obtained in different LED light sources treatments: Shoot biomass and S/R ratio of romaine lettuce were the highest under mixed red+blue LEDs. S/R ratio of head lettuce was higher under mixed red+blue+white LEDs than red+blue LEDs. The others showed no difference in LED light treatment. Shoot biomass, total biomass and S/R ratio of green lettuce, head lettuce and pak-choi were highest in the higher red ratio (5 : 1) on irradiation time of red : blue LED ratios. By the different duty ratio (red+blue and red+blue+white LEDs), Under the mixed light of red+blue, shoot and root biomass of crown daisy and romaine lettuce were high in duty ratio of 100% and 99%, and S/R ratio was highest in all the 6 kinds in duty ratio of 97%. All the 6 kinds showed a fine growth state in low duty ratio (97%). Green lettuce, romaine lettuce and pak-choi showed relatively high shoot biomass and total biomass in low duty ratio of 97% under the mixed light of red+blue+white. S/R ratio of romaine lettuce and head lettuce were highest in the duty ratio of 97% with red+blue+white LEDs. Thus, we can cultivate stably without reference to external factors, if we use appropriate light sources and light quality in closed-type plant factory.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.2
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• pp.86-92
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• 1989

This experiment was conducted to find out the effect of soil improvement on the changes of soil physical properties and the silage yield of corn in the newly-reclaimed sloped land. Corn (Suweon 19) was cultivated under the six different treatments at Songjeong loam, 20 percent slope, during 1985 to 1987 and various soil physical properties and silage yield were investigated. Growing Degree Days of corn during the growing season were $820.6^{\circ}C$ in 1985, $810.2^{\circ}C$ in 1986, and $812.4^{\circ}C$ in 1987. The changes of soil bulk density were high variances by different treatments in 1st year, but sluggish in 2nd year. In 3rd year, the control plot was the highest, but the integrated improvement plot was the lowest than the other plots. Soil hardness was reduced in subsoiling and integrated improvement plot with deep plowing, and water stable aggregates and air permeability were higher in these plots. Moisture retention was no differences between treatments. Dry matter yield of corn was decreased in the 2nd year than the 1st year, but increased in the 3rd year. Increasing ratio of yield was in the order of integrated improvement > subsoiling > lime > phosphate > compost > control plot. Correlation among the dry matter yield and soil physical properties were significant at 1%, but moisture retention of soil was not significant at 5%.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.6
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• pp.79-88
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• 2012

The purpose of this study were to classify the Y/N in participating the urban farming and to analyze the intention in farm village experience tourism, reason to participate and non-participation, the positive image and negative image between the urbanite group experience in urban farming and the other group that does not experience it. Questionnaire was implemented to the metropolitan urbanite who visited exemplary field farmhouse and urban recreation space to analyze the comparison of groups that experience or do not experience urban farming. The result of this research is as follows: first, experiencing urban farming are relatively less in willingness to participate in the farm village tourism experience than those who do not experience it. Second, the largest reason to participate in farm village tourism experience is found to be the natural environment of farm village tourism experience that is different from that of the city and the effect on children's education. Third, most answers on the reason for not participating in farm village tourism experience is because of the busy daily life. Fourth, urbanite have positive image in general about farm village tourism experience. Especially, when the comparison between the groups was made, it was showed that the difference in understanding the crops growing and the natural environment difference in the city. Fifth, about the negative image on the farm village tourism experience, it showed the difference in understanding the unfamiliar scenery, shortage of eye catching and fun, and the necessity and cost between the groups. Consequently, this study may be significant in the recognition of the farm village tourism experience on urbanite were checked, it was revealed that Y/N experience in the urban farming made negative influence to the willing.

• Journal of Bio-Environment Control
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• v.7 no.1
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• pp.63-70
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• 1998

This study was carried out to investigate the interaction of selenate and sulfate ion in nutrient solution supplyed with selenate ion. At early growth stage, the growth of Mongolian wormwood was best at 3mM sulfate ion and 2mg/$\ell$Na$_2$SeO$_4$ treatment. As they were grown and matured, at the later growth stage, the effect of antagonism between selenate and sulfate ion on the growth of each plant decreased. At supplying with selenate ion in nutrient solution, the uptake of selenate by plant had negative correlation with sulfate ion concentration in nutrient solution. The higher sulfate ion concentration, the less selenium uptake. However, the effect of antagonistic interaction of selenate and sulfate ion on the selenium uptake increased with plant age. Whereas, the uptake of sulfate ion had positive correlation with sulfate ion concentration in nutrient solution at supplying with selenate ion in nutrient solution. The uptake of sulfate ion increased with increase of sulfate ion concentration in nutrient solution. The effect of this interaction with selenate and sulfate ion increased with growth and maturity of plant. However, at 3mM sulfate ion concentration in nutrient solution, sulfate ion concentration in plant tissue decreased markedly.

• Journal of the Korean association of regional geographers
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• v.6 no.3
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• pp.37-52
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• 2000

Generally speaking, the metropolitan agricultural regions have some advantages from the high accessibility to markets. But agriculture inevitably rests on the biological process. This study shows what characteristics of the agricultural management are found in these less favored metropolitan areas with bad natural conditions and how farm household live there. From the view point of farm household, the quality of labors they can get is quite low, and insufficient in quantity. The shortage of labor can be made up for the farming on Trust Farming System And the relatively less favored agricultural conditions prevent people from immigrating into these kind of areas, if they don't have any relationship with there. With bad natural conditions, the farm households usually cultivate relatively small areas for the purpose of self-sufficiency, and with smaller cultivating units(Baemi) of the land than in open fields. The scale of the agricultural management is largely affected by the ages of agricultural managers. The more aged the managers are, the smaller scale of the agricultural management. How to use lands is determined in accordance with the natural conditions such as percentage of sunshine and accessibility to drainage facilities -the two major factors- and more. Either owner-run farmlands or leased farmlands doesn't show any difference in each growing crops. Depending on the conditions of the lands, rice paddy is used for growing rice and field is used for growing self sufficient plants including vegetables for the farm household. Although the lack of infrastructure causes the inconvenience of living, and there exist less favored agricultural conditions, this kind of life and agricultural management style -self-sufficiency type- seems to be sustained quite longer. The less favored natural conditions for farming keeps the agricultural management style from being developed to be the level of commercialization. And the poor economic situation of farmers are continuing again and again. With the result of this study, there should be two conditions to be established previously if they want to develop these regions. First, each farm household should get to know of the importance of commercialization and try to spread it. The commercialization. should be attained through the expansion of the environmental friendly agriculture and the improvement of the previously established distribution system of the crops. Secondly, there should be a support from the government. The support will include the expansion of the infrastructures for fanning to improve the fanning conditions and the compensation system directly from the government to the farmers.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.1
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• pp.56-64
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• 2001

Composting of livestock feces is economic and safe process to decrease the possibility of direct leakage of organic pollutants to ecosystem from commercial and environmental point of view. This study was conducted with three different experiments related to composting of livestock feces. The purpose of experiment 1 was to investigate changes of characteristic of compost pile during composting period by low temperature in cold season. To compare composting effect of experimental compost pile and control pile exposed in cold air, experimental compost piles were warmed up by hot air until their temperatures were reached at $35^{\circ}C$. Sawdust, Ricehull and Ricestraw were mixed with livestock feces as bulking agent. The highest temperatures of compost pile during composting period were in sawdust, rice hull, rice straw, and control were $75^{\circ}C$, $76^{\circ}C$, $68^{\circ}C$, $45^{\circ}C$ respectively. Moisture content, pH, C/N and volume of compost were decreased during composting period. Experiment 2 was carried out to study utilization effect of compost by plant. A corn was cultivated for 3 years on fertilized land with compost and chemical fertilizer. The amount of harvest and nutrition value of corn were analyzed. In first year of trial, the amount of harvest of corn on land treated with compost was lower by 20% than that of land treated with chemical fertilizer. In second year, there was no difference in yield of com between compost and chemical fertilizer. In third year, the yield of com on land fertilized with compost was much more than that of land fertilized with chemical fertilizer. The purpose of experiment 3 was to estimate the decrease of malodorous gas originating from livestock feces by bio-filter. Four types of bio-filters filled with saw dust, night soil, fermented compost and leaf mold were manufactured and tested. Each bio-filter achieved 87-95% $NH_3$ removal efficiency. This performance was maintained for 10 days. The highest $NH_3$ removal efficiency was achieved by leaf mold on the first day of operation period. It reduced the concentration of $NH_3$ by about 95%. Night soil and fermented compost showed nearly equal performance of 93 to 94% for 10 days from the beginning of operation. The concentration of hydrogen sulfide and methyl mercaptan originating for compost were equal to or less than $3mg/{\ell}$ and $2mg/{\ell}$, respectively. After passing throughout the bio-filter, hydrogen sulfide and methyl mercaptan were not detected.

• Journal of the Korea Organic Resources Recycling Association
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• v.13 no.4
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• pp.89-99
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• 2005

The golf courses more than about 200 are operating in Korea. From the golf courses, a great amount of turfgrass clippings tend to increase, steadily. Materials used in the experiment were Creeping Bentgrass(CB), Kentucky Bluegrass(KB), Korean Lawngrass(KL), rice bran and composted chicken drop. Treatments are CB, KB, and KL. The temperature during the composting of all treatments increased rapidly and reached at the highest temperature($57.9^{\circ}C$, $67.8^{\circ}C$, $74.3^{\circ}C$) within 20 days, and then stabilized to the range of $35.2{\sim}41.6^{\circ}C$ at the 30th day. The pH values of all treatments decreased on the first day. However, they were increased rapidly after three days and decreased again on 10~20 days. The pH values of all treatments at the final day were stabilized to the low alkali levels. The contents of total carbon during the period of composting tend to decrease and total nitrogen was increased for factor of reduction of volume. CEC value of all treatments during the period of composting tends to increase. The round paper chromatogram of extracted solution of KL sample was the sharpest and clearest among all treatments. The G.I. values of CB, KB, and KL in 30th day of composting were about 95.1, 77.7, and 98.7 in germination test using chinese cabbage, respectively. Conclusively, all turfgrass clippings used in this experiment were composted well, suitable as composting products standardized by KSC. The maturity of the final compost samples is best in KL, followed by CB and KB treatments. The turfgrass compost can contribute to the plant cultivation for environment-friendly farm, and the results of this study can become the basic data of turfgrass clippings compost. Further research on the mixing ratio of each material is required to produce compost of good quality.