• Journal of Marine Bioscience and Biotechnology
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• v.11 no.1
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• pp.23-28
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• 2019

For successful microalgal biodiesel production, the strain should be selected carefully. Fast growth rate and high fatty acid contents are desired traits for algal biodiesel production. In ocean cultivation of microalgae, seawater temperature slowly changes over seasons, and rotating algal strains in accordance with their optimal temperature could improve overall productivity. Additionally, use of indigenous strain is preferred to alleviate potential impacts on the environment. In this study, five strains of Tetraselmis sp. from nearshore of Youngheung Island, Incheon, Korea, were isolated during winter and characterized for their growth patterns and fatty acid compositions in the low temperatures ($5-15^{\circ}C$). The five strains showed various characteristics in optimal growth temperature, fatty acid contents, and compositions. Compared with a strain of Tetraselmis sp., isolated from Ganghwa island in a previous study, a rapid-growing strain with 237% higher biomass productivity and an oleaginous strain with twice higher fatty acid contents at $10^{\circ}C$ were isolated. The oleaginous Tetraselmis strain showed the highest fatty acid productivity among the strains, having 438% higher productivity than the previous strain. Using the new isolates in the seasons with low seawater temperature would improve microalgal fatty acid productivity in ocean cultivation.

• Journal of Ginseng Culture
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• v.6
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• pp.51-79
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• 2024

In the 1970s and 1980s, during the nascent phase of ginseng disease research, efforts concentrated on isolating and identifying pathogens. Subsequently, their physiological ecology and pathogenesis characteristics were scrutinized. This led to the establishment of a comprehensive control approach for safeguarding major aerial part diseases like Alternaria blight, anthracnose, and Phytophthora blight, along with underground part diseases such as Rhizoctonia seedling damping-off, Pythium seedling damping-off, and Sclerotinia white rot. In the 1980s, the sunshade was changed from traditional rice straw to polyethylene (PE) net. From 1987 to 1989, focused research aimed at enhancing disease control methods. Notably, the introduction of a four-layer woven P.E. light-shading net minimized rainwater leakage, curbing Alternaria blight occurrence. Since 1990, identification of the bacterial soft stem rot pathogen facilitated the establishment of a flower stem removal method to mitigate outbreaks. Concurrently, efforts were directed towards identifying root rot pathogens causing continuous crop failure, employing soil fumigation and filling methods for sustainable crop land use. In 2000, adapting to rapid climate changes became imperative, prompting modifications and supplements to control methods. New approaches were devised, including a crop protection agent method for Alternaria stem blight triggered by excessive rainfall during sprouting and a control method for gray mold disease. A comprehensive plan to enhance control methods for Rhizoctonia seedling damping-off and Rhizoctonia damping-off was also devised. Over the past 50 years, the initial emphasis was on understanding the causes and control of ginseng diseases, followed by refining established control methods. Drawing on these findings, future ginseng cultivation and disease control methods should be innovatively developed to proactively address evolving factors such as climate fluctuations, diminishing cultivation areas, escalating labor costs, and heightened consumer safety awareness.

• Korean Journal of Environmental Agriculture
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• v.42 no.3
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• pp.177-183
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• 2023

Rendering, is attracting attention as a technology that can stably and quickly process livestock carcasses. However, large amounts of livestock carcass solid residues are discharged in this process and limited methods are available for recycling them. In this study, rendered animal carcass solid residues were pyrolyzed to produce carbonized materials (350℃; RACR-C) and their chemical properties were investigated. Further, RACR-C were applied to cabbage cultivation for investigating their crop growth characteristics and soil improvement effects. RACR-C contained large amounts of fertilizer components such as nitrogen and phosphorus, and showed no toxic effects on the seedling growth of crops. The content of water-soluble nutrients released from RACR-C under the reaction time increased rapidly within 30 min, but was insignificant compared to the total content. Thus, most fertilizer components in RACR-C were not readily soluble in water. The optimal application amount for applying RACR-C to cabbage cultivation based on the changes in cabbage growth, inorganic content, and soil chemistry was 200 kg/10a. Overall, pyrolysis of solid residues after rendering livestock carcass to produce carbonized material as a soil improver is an effective method to recycle the waste discharged from the rendering process.

• Korean Journal of Agricultural Science
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• v.33 no.2
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• pp.179-193
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• 2006

Technical efficiency of semiforcing watermelon growers is 0.8248 on average, and distributed between 0.6744 and 0.9268. The result showed that semiforcing watermelon growers had by 18% of technical inefficiency and could be assumed that increasing technical efficiency could induce watermelon production more increase. Consequently, if growers' technical efficiency were improved while other environments were constant, watermelon production could be increased. Following the results from the inefficiency effect model, all assumption coefficient such as growers age etc, are significant at 10% level. Estimate of dispersion parameter ${\gamma}$ is 0.89, which confirms those differences between practical output and frontier output were derived from the technical efficiencies among growers. Differences of production system between high and low level growers in production efficiency were showed at side altitude, ventilation and heat-retaining in section of facilities and automation, soil test and calcium application in section of environment management, transplant preparation and duration of pollination in section of crop management and shipment place, sorting degree and management record analysis in section of business management respectively. As a result of analyzing consulting data by using standard diagnosis table of watermelon cultivation under structure which cultivated on semi-forced watermelon growers, gap between high and low level growers was 7.0 points in facility automation section, 7.1 points in environment section, 8.8 points in crop management section and 13.6 points in business management section, respectively, which were the biggest one among them. In case of excluding information-related items from the evaluation index of business management section, changes of business achievement are to occur. Therefore, it is recommended for us to review the standard diagnostic table of watermelon cultivation under structure by dividing evaluation index of management section into management and information.

• Journal of the Korean Geographical Society
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• v.32 no.4
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• pp.463-478
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• 1997

This paper examines the impact of large-scale tidal flat reclamations on environment by analyzing land use change, ocean cultivation, water quality, sea biota and climate in Shiwha, Sosan and Saemankeum districts. The data used in this paper include Landsat TM images and documents related to population, industry, water quality, sea biota and climate at the time of the pre- and post-reclamation. Many times of field reclamations contribute to the creatation of newly available land for urban and industrial development, but cause environmental degradation significantly. The increase of pollution load and the change of coastal ecology, also cause some changes of climatic element such as relative humidity. As tidal flats were reduced, the area of ocean cultivation and the population of fishing industries were decreased. Conceming the sustainable development. it is necessary to carry out a careful environmental impact assessment accumulating monitoring environmental data continuously by using GIS techniques.

• Journal of Korea Water Resources Association
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• v.45 no.10
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• pp.1051-1067
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• 2012

Increased use of water curtain facilities to keep green house warm during winter cultivation has been known to cause excessive groundwater ion which might lead to decline of groundwater level, resulting in streamflow depletion. Therefore it is required to quantitatively assess the effects of groundwater ion on the streamflow depletion such as magnitude and extent. The objective of this study is to assess the change of stream-aquifer interaction according to groundwater ion near stream. To this end, a green house cultivation land in Sooha-ri, Sindun-myun, Icheon-si, Gyonggi-do was selected as a field experimental site, and monitoring wells were established near and within stream to observe the water level and temperature changes over a long period of time. From the observed water level and temperature data, it was found that the river reach of interest changed to a losing stream pattern during the winter cultivation season due to groundwater level decline around pumping wells near the stream. The continuous exchange rates between stream and aquifer were estimated by plugging the observed water level data series into the experimental relation between head difference and exchange rate, showing the streamflow depletion by 16% of the groundwater pumping rate in Feb, 2011.

• Journal of Bio-Environment Control
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• v.9 no.2
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• pp.101-106
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• 2000

The practicality of utilizing ventilation pipe to enhance soybean sprout productivity by lowering commodity temperature and resultant sprout rot was tested. The ventilation pipes with holes for aeration were vertically installed inside of a sprout cultivation container prior to adding soaked soybean seeds. The time-series changes in sprout commodity temperature and resultant growth, yield, marketable sprout percentage, and rot of soybean sprouts were measured. The ventilation pipes effectively decreased sprout commodity decreased sprout commodity temperature by 4.7$^{\circ}C$. Ventilation pipes also enhanced sprout yield and marketable sprout percentage by 3.9% and 4.0%, respectively, while reducing sprout rot by 4.1%. In conclusion, ventilation pipe seems a practical and effective non-chemical method to enhance the productivity of soybean sprouts.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.252-263
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• 2018

In this research, we performed a SWOT analysis to analyze the feasibility of cultivating tropical fruits in Korea, using the mango as a case study. The opportunities for domestic tropical fruit (mango) cultivation are that the domestic cultivation environment is improving due to global warming, the consumer market is expanding due to the increase in domestic demand, and some local governments are supporting the cultivation of tropical fruits as a new high-income crop. The strengths are that it is possible to produce high quality fresh fruits in Korea and that they are still distributed in small quantities, so they can be differentiated from imported ones. There are regular customers and the mango is recognized as a medicinally functional fruit. The threats are that the price competitiveness of imported goods is likely to be further strengthened due to the implementation of the FTA and that it is difficult to cope with the unpredictable climate changes, such as heavy snowfall and extremely cold weather. The weak points are that the initial investment cost is high, the operating costs such as heating bills are also very high, and there is no supply system for the chemicals, fertilizers and cultivation technology required for tropical fruits. In order for tropical fruits such as mangoes to become major fruits, we must make full use of these strengths and opportunities while, at the same time, complementing the weaknesses and eliminating the threats in the value chain.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.444-451
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• 2022

Recently, long-term cultivation is becoming more common with the increase in tomato hydroponics. In hydroponics, it is very important to supply an appropriate nutrient solution considering the nutrient and moisture requirements of crops, in terms of productivity, resource use, and environmental conservation. Since seasonal environmental changes appear severely in long-term cultivation, it is so critical to manage irrigation control considering these changes. Therefore, this study was carried out to investigate the effect of irrigation volume on growth and yield in tomato long-term cultivation using coir substrate. The irrigation volume was adjusted at 4 levels (high, medium high, medium low and low) by different irrigation frequency. Irrigation scheduling (frequency) was controlled based on solar radiation which measured by radiation sensor installed outside the greenhouse and performed whenever accumulated solar radiation energy reached set value. Set value of integrated solar radiation was changed by the growing season. The results revealed that the higher irrigation volume caused the higher drainage rate, which could prevent the EC of drainage from rising excessively. As the cultivation period elapsed, the EC of the drainage increased. And the lower irrigation volume supplied, the more the increase in EC of the drainage. Plant length was shorter in the low irrigation volume treatment compared to the other treatments. But irrigation volume did not affect the number of nodes and fruit clusters. The number of fruit settings was not significantly affected by the irrigation volume in general, but high irrigation volume significantly decreased fruit setting and yield of the 12-15th cluster developed during low temperature period. Blossom-end rot occurred early with a high incidence rate in the low irrigation volume treatment group. The highest weight fruits was obtained from the high irrigation treatment group, while the medium high treatment group had the highest total yield. As a result of the experiment, it could be confirmed the effect of irrigation amount on the nutrient and moisture stabilization in the root zone and yield, in addition to the importance of proper irrigation control when cultivating tomato plants hydroponically using coir substrate. Therefore, it is necessary to continue the research on this topic, as it is judged that the precise irrigation control algorithm based on root zone-information applied to the integrated environmental control system, will contribute to the improvement of crop productivity as well as the development of hydroponics control techniques.

• Korean Journal of Remote Sensing
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• v.37 no.3
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• pp.637-648
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• 2021

In order to support the establishment of a farming plan, it is important to preemptively evaluate crop changes and to provide precise information. Therefore, it is necessary to provide customized information suitable for decision-making by farming stage through scientific and continuous monitoring using drones. This study was carried out to support the establishment of the farming plan for ground vegetable. The cultivation management map of each information was obtained from preliminary study. Three cultivation management maps include 'field emergence map', 'stress map' and 'productivity map' reflected spatial variation in the plantation by providing information in units of plants based on 3-dimensions. Application fields of the cultivation management map can be summarized as follows: detect miss-planted, replanting decision, fertilization, weeding, pest control, irrigation schedule, market quality evaluation, harvest schedule, etc.