• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.243-245
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• 2007

This study was begun to classify the paddy fields by the rice varieties and to monitor the temporal change in rice growth using SAR backscatter coefficients $({\sigma}^{circ})$. For nine fine-beam mode images of Radarsat-1 SAR, a growing period time-series of backscatter coefficients was set up from April to October in 2005, and was compared with the field-measured rice growth parameters such as LAI (leaf area index), plant height, fresh and dry biomass, and water content in grain and plant for 45 parcels in Dangjin-gun, Chungcheongnam Province, South Korea. The average backscatter coefficients for early-maturing rice varieties (13 parcels) were ranged from -18.17dB to -6.06dB and were lower than for medium-late maturing rice varieties during most of the growing season. At around the heading stage (July 30) for early-maturing rice, both rice crops showed the highest backscatter coefficient values and the difference was the greatest before harvesting early-maturing rice. The temporal difference in backscatter coefficients between rice varieties was expected to play a key role to identify early-maturing rice fields. On the other hand, comparison with field-measured rice growth parameters showed that the backscatter coefficients decreased or stayed on the plateau after heading stage even though the growth of rice canopy advanced.

• Journal of Soil and Groundwater Environment
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• v.16 no.6
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• pp.66-78
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• 2011

It is getting difficult to manage water resources in South Korea because more than half of annual precipitation is concentrated in the summer season and its intensity is increasing due to global warming and climate change. Artificial recharge schemes such as well recharge of surface water and roof-top rainwater harvesting can be a useful method to manage water resources in Korea. In this study, potential artificial recharge site is evaluated using geographic information system with hydrogeological and social factors. The hydrogeological factors include annual precipitation, geological classification based on geological map, specific capacity and depth to water level of national groundwater monitoring wells. These factors were selected to evaluate potential artificial recharge site because annual precipitation is closely related to source water availability for artificial recharge, geological features and specific capacity are related to injection capacity and depth to water is related to storage capacity of the subsurface medium. In addition to those hydrogeological factors, social aspect was taken into consideration by selecting the areas that is not serviced by national water works and have been suffered from drought. These factors are graded into five rates and integrated together in the GIS system resulting in spatial distribution of artificial recharge potential. Cheongsong, Yeongdeok in Gyeongsangbuk-do and Hadong in Gyeongsangnam-do, and Suncheon in Jeollanam-do were proven as favorable areas for applying artificial recharge schemes. Although the potential map for artificial recharge in South Korea developed in this study need to be improved by using other scientific factors such as evaporation and topographical features, and other social factors such as water-curtain cultivation area, hot spring resorts and industrial area where groundwater level is severely lowered, it can be used in a rough site-selection, preliminary and/or feasibility study for artificial recharge.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.4
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• pp.276-280
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• 2013

D. kaki and D. lotus are used as rootstocks for astringent persimmons in Korea but characteristics of their seedlings have not been determined. In this experiment, their seeds were sown in 3-L pots on April 18 and the seedlings were grown until October 24. Growth and nutrient absorption were compared at the end of the season after destructively harvesting the seedlings. Seedling growth of D. lotus was much faster than that of D. kaki in terms of total stem length, stem diameter, and number of leaves. However, chlorophyll value and specific leaf weight were higher in D. kaki than in D. lotus. Dry weight of D. lotus was 3.6- and 3.7-fold higher than that of D. kaki in above-ground parts and the root, respectively. D. kaki seedlings were characterized by higher concentrations of N, P, K, Ca, and Mg in the leaves, stem, or the root. However, total contents of the elements were 1.8- to 3.7-fold higher in a D. lotus seedling due to its greater dry weight. Since D. lotus seedlings absorbed more inorganic elements on a tree basis and grew more vigorously than D. kaki seedlings, the level of fertilization for astringent persimmons should be adjusted depending on rootstocks to maintain the trees at the optimum vigor.

• Korean Journal of Food Science and Technology
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• v.21 no.2
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• pp.180-184
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• 1989

Clarification of the juice extracted from stored Fuji apples was studied with pectolytic enzyme and pH control, separately and in combinations. In the separated treatment, the clarity of the juice was increased with the treated enzyme amount. The juice adjusted pH to 3.5 with malic acid had the highest clarity in pH range from 3.5 to 5.0, but this juice was not acceptable because of high acidity. In combination of the two treatment, the clarity of the juice treated with the enzyme at pH 4.0 was higher than that of the juice without the enzyme, and the juice with ligh trasmittance of about 92% could be obtained at the pH by addition with one-third amount of enzyme which was used for clarification of the juice extracted from the fresh apples at harvesting season.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.1
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• pp.62-66
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• 2003

Mass consumption of the surplus onion in the period of harvesting season by processing to various value-added functional food products would be one of the counterplot for stable market. This study was to develop functional sponge cakes with addition of onion powder, using physiochemical properties and sensory evaluation. The specific gravity and viscosity tended to increase according to the addition of onion powder. The water content was highest mark on the 4% onion powder added-cake. The color of lightness, yellowness, and redness of cake crust tended to decrease with the addition of onion powder. The addition of onion powder showed decrease in lightness and yellowness and increase in redness of cake crumb. The specific loaf volume was superior with the addition of 4% onion powder. The resilience, fracturability and adhesiveness showed a difference from the control. Sensory evaluation of cake indicated that addition of onion powder especially at the level of 2, 4%, enhanced appearance flavor, mouth feeling, and overall acceptability.

• Korean Journal of Agricultural Science
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• v.28 no.2
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• pp.147-161
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• 2001

Efficiency and competitive power in agribusiness management has became important issue due to the rapid changes in farming environment under new WTO agreement. To increase competitive power, small-sized petty farm should be restructured to be specialized large-scaled farming system. Trust farming corporation(TFC) has been introduced to increase farm productivity and competitive power through large scale farming system and refined management skills. Eventually, TFCs are expected to revitalize rural economy. TFCs are increasing in numbers, but they are unsatisfactory in quality often with insolvent operations. The typical problems with TFCs are internal conflicts among members, lack of management abilities and incentives, inefficiency in machinery use, and insolvent operations. The self effort by members and legal-institutional assistance can alleviate the negative factors against the rational for cooperative management and sustain TFCs. This study identifies the management problems of TFCs. To provide the methods for increasing management efficiency, improving rational management skills, and hence to help revitalizing the rural economy with competitive power, 20 TFCs in Nonsan County is surveyed. The major findings are as follows; 1) According to the survey result of 20 trust farming corporations, investments on the accumulation of knowledges and information, accounting management, machinery management are required due to the present lack of management/accounting ability. There also exist problems associated with revenue sources, labor uses, and public recognition. To increase management efficiency under current situation, corporations should import active business plans with expanding farming execution and off-farm season business. 2) Based on the result of corporations' business analysis, more than 50% of the corporations were not able to provide profit dividends to the members. It suggests that trust farming corporations need appropriate and stable revenue sources to sustain business. It is also required that corporations should reduce their excessive expenditure on fixed assets. 3) Theoretical amounts of consignment fees for tillage operation, planting, and harvesting were found to be 338,874 won, 216,596 won, and 332,318 won, respectively. Although actual levels of fee are 110%~120% of these theoretical levels of consignment fee, corporations' expected fee levels could not be acheived because of competency of consignment market.

• Journal of The Korean Society of Grassland and Forage Science
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• v.10 no.2
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• pp.89-95
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• 1990

This experiment was carried out to determine the effects of nitrogen(N) fertilizer levels (0, 120, 240 and 360kg $ha^{-1}Y^{-1}$ Y-') on seasonal grass growth, dry matter (DM) yield and botanical composition in pasture under shade condition. Investigation date was on 7 , 14, 21, 28 and 35 days after harvesting in spring (May), summer (July) and autumn (Sept.), 1988, respectively. Shade degree was controlled artificially ca. 45-50%, and each annual level of N was distributed 5 times equally. Grass growth and DM productivity were most vigorous in spring. Higher DM yield was produced with N 240 kg spring, and Nl2Okg in summer and autumn. Higher significant relationships, in spring, were found between grass height and DM, and N level and DM yield. However, low relationships were observed between those in summer and autumn. In botanical composition, grass coverage was decreased in summer and autumn, and bareland was increased, especially in higher N plots. Based on the results, it is suggested that 200kg $ha^{-1}$ of N in this experiment is more effective for forage production and pasture persistence. Also a littie more amount of N (50-70kg $time^{-1}$) in spring, and low level of N (20-30kg $time^{-1}$) in summer and autumn may be desirable.

• Korean Journal of Breeding Science
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• v.41 no.1
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• pp.61-67
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• 2009

"Early Valley", is an early maturing potato cultivar with high yield potential. "Early Valley" is a clonal selection resulting from the cross between 'Suncrisp' and 'A87109-10'. It has medium plant height and light green foliage. "Early Valley" has medium flowering habit and white flowers. Tubers are smooth, yellow skin, light yellow flesh, round tuber shape, medium eye depth, and medium dormancy and good keeping quality. It has stable yield under wide range of climatic conditions. "Early Valley" is resistance to late blight, but moderately susceptible to common scab and hollow heart. This cultivar is also resistant to potato rotting at harvesting during the raining season. "Early Valley" has high level of antioxidant activity (about three times higher) and vitamin C (higher by 40%) than the 'Superior'. This cultivar has high level of tuber uniformity and capable of yielding 36.56 t/ha which is 17.07% higher than the control potato cultivar 'Superior' under optimum agronomical practices.

• Journal of Animal Science and Technology
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• v.63 no.2
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• pp.339-353
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• 2021

This study aimed to assess the causality of different climate variables on the production of whole crop maize (Zea mays L.; WCM) in the central inland region of the Korea. Furthermore, the effect of these climate variables was also determined by looking at direct and indirect pathways during the stages before and after silking. The WCM metadata (n = 640) were collected from the Rural Development Administration's reports of new variety adaptability from 1985-2011 (27 years). The climate data was collected based on year and location from the Korean Meteorology Administration's weather information system. Causality, in this study, was defined by various cause-and-effect relationships between climatic factors, such as temperature, rainfall amount, sunshine duration, wind speed and relative humidity in the seeding to silking stage and the silking to harvesting stage. All climate variables except wind speed were different before and after the silking stage, which indicates the silking occurred during the period when the Korean season changed from spring to summer. Therefore, the structure of causality was constructed by taking account of the climate variables that were divided by the silking stage. In particular, the indirect effect of rainfall through the appropriate temperature range was different before and after the silking stage. The damage caused by heat-humidity was having effect before the silking stage while the damage caused by night-heat was not affecting WCM production. There was a large variation in soil surface temperature and rainfall before and after the silking stage. Over 350 mm of rainfall affected dry matter yield (DMY) when soil surface temperatures were less than 22℃ before the silking stage. Over 900 mm of rainfall also affected DMY when soil surface temperatures were over 27℃ after the silking stage. For the longitudinal effects of soil surface temperature and rainfall amount, less than 22℃ soil surface temperature and over 300 mm of rainfall before the silking stage affected yield through over 26℃ soil surface temperature and less than 900 mm rainfall after the silking stage, respectively.

• Fisheries and Aquatic Sciences
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• v.25 no.2
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• pp.101-116
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• 2022

The harvesting season of lompa fish, Thryssa baelama, through sasi, indigenous knowledge in resources management, in Haruku Village has become a socio-cultural event that attracts many people. The sasi of lompa fish has been conducted for hundreds of years. Information on the bioecology aspect of lompa fish is limited, while this information is crucial for lompa fish sustainability through the sasi approach. This study aimed to investigate some population parameters of lompa fish, its sustainability status, and proposed a sustainable management strategy for the lompa fishery of Haruku Village. Fish population parameter covers length-weight relationship, growth pattern, size distribution, sex ratio, and the body condition index. The sustainability status was assessed following the Rapfish approach. Fisheries management strategy was performed using a conceptual model framework based on Driver Pressure State Impact Response. The research shows that the total length varies between 9.2-14.3 cm. A high relationship was found between total length and weight, and the growth pattern was an allometric negative. There was a difference in sex ratio between males and females, with females dominant. The body condition index varies over time, probably due to reproductive status. The overall sustainability status was at fair condition (61.60%), with the ecological domain having the highest sustainable status (71.07%) and considered sustain. In comparison, the technological domain had the lowest sustainability status (52.58%) and was considered fair sustain. There were seven management strategies proposed for sustainable management for the lompa fishery.