• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.3
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• pp.305-309
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• 1983

To know the effect of desaltation in the reclaimed tidal fields on the succession of vegetation and on the root hair formation of paddy rice, reclaimed fields in Kang Hwa Island, Nam-Yang Bay and Ke-Hwa Island were investigated during summer crop season in 1982. The obtained results can be summarized as followings. l) In the highly salty and water logged areas of reclaimed tidal fields, the first dominating species of higher plant were observed to be Salicornia herbacea L. and Suaeda japonica Makino. With the continued desaltation, Chemopodium virgatum Thumb. occurred in the vegetation. After this transition, the dominating species were composed of Scirpus maitimus L. and Phragmites communis Trin. At the S. maitimus and P. communis dominating salinity level, rice cultivation was safe from the salt damage. 2) In the water logged area, Artemisia capillaria Thunb. and Aster tripolium L. took the place of dominating species after S. herbacea and S. japonica. At this salinity level, graminaceous weeds began to immigrate. 3) In dry areas, Suaeda asparagoides Makino and Suaeda maritima were the first appearing dominant species. Atriplex subcordata Kitakawa was also observed in sucy dry areas, but colony formation was not observed. 4) Plants immigrated slowly into dry areas from the already vegetated water logged areas with the continuation of desaltation. 5) The high soil salinity level affected the root hair formation of rice by reducing both the rate of root hair formation and the length of root hairs.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.4
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• pp.385-397
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• 1982

The climatic impacts have been the environmental constraints with soil characteristics to achieve self sufficiency of food production in Korea. In this paper, the distribution and appearance of impacts and the changes in climatological status due to recent trend of early transplanting of rice are widely discussed to derive some countermeasures against the impacts, being focussed on cultural A long term analysis of the climatic impact appearances of the last 74 years showed that drought, strong wind, flood, cold spell and frost were the major impacts. Before 1970's, the drought damage was the greatest among the climatic impacts; however, the expansion and improvement of irrigation and drainage system markedly decreased the damage of drought and heavy rain. The appearance of cold damage became more frequent than before due to introduction of early transplanting for more thermophilic new varieties. Tongillines which were from Indica and Japonica crosses throw more attention to cold damage for high yields to secure high temperature in heading and ripening stages and lead weakness to cold and drought damage in early growth stage after transplanting. The plants became subject to heavy rain in ripening stage also. For the countermeasures against cold damage, the rational distribution of adequate varieties according to the regional climatic conditions and planting schedule should be imposed on the cultivation. A detoured water way to increase water temperature might be suggestable in the early growth stage. Heavy application of phosphate to boost rooting and tillering also would be a nutritional control method. In the heading and ripening stages, foliar application of phosphate and additional fertilization of silicate might be considerable way of nutritional control. Since the amount of solar radiation and air temperature in dry years were high, healthy plants for high yield could be obtained; therefere, the expansion of irrigation system and development of subsurface water should be performed as one of the national development projects. To minimize the damage of strong wind and rainfall, the rational distribution of varieties with different growing periods in the area where the damage occurred habitualy should be considered with installation of wind breaks. Not only vertical windbreaks but also a horizontal wind break using a net might be a possible way to decrease the white heads in rice field by dry wind. Finally, to establish the integrated countermeasures against the climatic impacts, the detailed interpretation on the regional climatic conditions should be conducted to understand distribution and frequency of the impacts. The expansion of observation net work for agricultural meteorology and development of analysis techniques for meteorological data must be conducted in future together with the development of the new cultural techniques.

• Journal of Practical Agriculture & Fisheries Research
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• v.4 no.1
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• pp.55-64
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• 2002

This study was carried out to determine agronomic and genetic characteristics of the production process in tropical yams(Dioscorea alata L.). To make clear the possibility of cultivation of tropical yams in the Suwon area, the growth of the aboveground parts and the enlargement of tuber of Dioscorea alata, were investigated. The aboveground parts of the plants whose sprouted mother tuber were planted in late April were grown slowly until the 70-days after planting and grown rapidly after. From about 50-days after plantation, total length of vines slowly decreased due to the burning of the branch vines of lower modes. With regard to the branching progressed to 4th for the solo yam and to 6th for purple yam. The secondary branches tended to grow better. When the formation of daughter tubers was observed at the 50-days after planting, their enlargement was very slow. The rapid growth of tubers began at the 40-days and continued to the 90-days. General components such as protein, fiber, and lipid were higher in D. opposita rather than in D. alata. Hardness of D. alata was 2696.2 while that of D. opposita was 4946.9. Lightness of D. alata was 73.99, being higher than that of D. opposita.

• Journal of the Economic Geographical Society of Korea
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• v.25 no.4
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• pp.451-468
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• 2022

Leading enterprises in contract farming are in control of agricultural production and influence the structure of the agricultural system in contract areas. This study focuses on the contract farming of potatoes for manufacturing chips, which uses a high proportion of domestic raw materials, and identifies the characteristics of contract farming between confectionery company 𐩒 and potato farms in Haean-myeon, Yanggu-gun, Gangwon-do. This study also analyzes the impact of contract farming on local agriculture from the perspective of the industrialization of agriculture. The results of this study demonstrated that contracting companies ensured the quality of potatoes and smooth agricultural operations by first preferentially selecting farmhouses with land that is easy to work with and then supplying the necessary agricultural machinery to promote the intensification of their work. In addition, contracting companies influenced the centralization of the agriculture sector by selecting farmhouses capable of contracting over a certain scale and guaranteeing them sales channels and the specialization of potato farming in contract areas, mainly through the supply of processing varieties and the spread of cultivation technology. The results confirmed that these three dimensions of contract farming promoted the industrialization of local agriculture.

• Journal of Environmental Impact Assessment
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• v.32 no.3
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• pp.157-165
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• 2023

In Korea, a major contaminant of farmland soils in the vicinity of abandoned mines is arsenic, for which the general soil reclamation method is contaminated soil stabilization and cover the stabilized soil with clean soil at a thickness of 40 cm. In a previous pot experiment study we confirmed the feasibility of a lower thickness (20 cm) of covering soil for such reclamation in abandoned coal mines, where arsenic contamination levels are generally lower than in metal mines. In this subsequent study a field experiment including rice plant cultivation in field test plots was conducted. For over 4 months, the transfer of arsenic from the contaminated soil to the unpolished rice grains was reduced by 44% when a clean soil covering with a thickness of 20 cm was applied. The maximum decrease (56%) was shown when the stabilization process was performed before the covering. These results reveal a lower thickness of clean soil covering has a high feasibility and it can increase cost-efficiency in the reclamation of an abandoned coal mine.

• Journal of Bio-Environment Control
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• v.32 no.3
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• pp.217-225
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• 2023

This experiment was conducted to investigate the effects of microwave irradiation on the growth and secondary metabolite contents of lettuce seedlings. Seedlings at three weeks after sowing were treated by a microwave oven for 0, 4, 8, and 12 seconds with 200 W. After cultivation in a close plant production system for 4 weeks, plant growth measurements and secondary metabolite analysis were performed. The results showed that the fresh and dry weights of the shoot and root, leaf area, leaf length, and the number of leaves were decreased as increasing the microwave treatment times. Chlorophyll a and b, total carotenoids were increased and total phenolics were decreased at the 12-second treatment compared to the 4-second treatment. Total flavonoid contents were decreased at the 8-second treatment compared to the control. These results suggest that the changes in the levels of secondary metabolites were caused by oxidative stress. Although there was no significant difference in secondary metabolite contents excluding total flavonoid contents on the microwave treatments compared to the control, the significant difference suggests that the microwave treatment of 200 W and 2.45 GHz may alter secondary metabolite contents of lettuce after 4 weeks.

• Journal of Practical Agriculture & Fisheries Research
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• v.17 no.1
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• pp.163-179
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• 2015

The aim of this study is to investigate to which degree farmers did the crop switching and cultivar renewal as a confrontational strategy to climate change, and which problems they had in that process, and then to provide the supporting plans for them. We conducted a questionnaire survey of 15 citrus farmers of the KNCAP graduates in Jeju Island. Most of the survey respondents agreed to the climate change of Jeju Island and the subtropical climate of its coastal area. The farmers have experienced irregular weather such as abnormal high temperature, frequent rain, and droughts, resulting in the harmful insects and new weeds attack. As the climate change strategies, they are adopting a greenhouse culture system, improving a soil drainage using reorganization of planting space, making a new pest management program, and trying to switch a crop to subtropical fruits. It is expected that 50% of the survey respondents have changed their crops or will do; and 73 % of them have changed cultivar or have a plan to do. Only a few farmers directly pointed to a reason for their efforts to change the crops or to renew the cultivars as the anti-climate change strategy, however, most farmers answered the reason was to increase profitability by meeting their consumers' tastes. Presently, it is not the anti-climate change strategy but increase of profitability by meeting the consumers' needs the reason why most of the survey respondents have changed their crops or renewed the cultivars, while a few of them switched their crops to a subtropical fruit trees due to climate change. On the crop switching, they had some difficulties such as a labor shortage, availability of land, operating costs and instable income. On the cultivar renewal, also, they encountered the lack of cultivating techniques for new cultivars and the dim future for the new market. In long-term perspective, Jeju's farmers need new information and educational programs about the effect of climate change on agriculture of Jeju, and cultivation techniques for new crops and new cultivars.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.33-33
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• 2020

Watermelon (Citrullus lanatus) is a non-seasonal, economically important, cucurbit cultivated throughout the world with Asia as a continent contributing the most. As part of the effort in diversifying watermelon genetic resources in the already cultivated group, this study was devoted to providing baseline data on morphological quality traits and health-beneficial phytonutrients of watermelon germplasm collections, thereby promoting watermelon research and cultivation programs. To this end, we reported morphological traits, citrulline, and arginine levels of watermelon genetic resources obtained from the gene bank of Agrobiodiversity Center, Republic of Korea, and discussed the relationship between each other. Diverse characteristics were observed among many of the traits. But, most of the genetic resources (>90%) were either red or pink-fleshed. Korean origin fruits contained intermediate levels of soluble solid content (SSC) while The USA, Russian, Tajikistan, Turkmenistan, Taiwan, and Uruguay originated had generally the highest levels of soluble solids. The citrulline and arginine contents using HPLC method were ranged from 6.9 to 52.1 mg/g (average, 27.3 mg/g) and 1.8 to 21.3 mg/g (average, 9.8 mg/g), respectively. The citrulline content determined using Citrulline Assay Kit was ranged from 6.5 to 42.8 mg/g (average, 27.0 mg/g). Resources with high citrulline and arginine levels contained low SSC. Whereas, red- and pink-colored flesh samples had less citrulline compared to yellow and orange. In addition to the profiling of morphological characters and phytonutrients, molecular marker characterization and identification of sources of resistance to diseases and pests are recommended for a more complete diversity analysis of watermelon genetic resources.

• Korean Journal of Environment and Ecology
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• v.38 no.2
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• pp.156-168
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• 2024

This study was carried out to provide fundamental data for forest land and the environment by investigating the vegetation structure and soil properties of forest land where Sarcodon impricatus are present. The study area was divided into the Quercus mongolica community, dominated by Q. mongolica and the Quercus variabilis community, a mixed forest with Q. variabilis, Q. mongolica and Pinus densiflora. Also, Calamagrostis arundinacea in the former community and Disporum smilacinum and Carex siderosticta in the latter community showed significant levels as indicator species. Both communities showed a strong correlation between available phosphate and pH, sand, and clay, and the high organic matter content and slightly acidic pH of the soil are believed to be related to the development of S. impricatus. The species appearing at the lower layer continue to dominate because the species appearing at the upper layer have secured realized niches. The site was distributed in a relatively humid place in a north-east direction, and soil was developed with a thin litter layer and low rock exposure. In the selected S. impricatus growing areas, vegetation centered on highly adaptable species to disturbance or external interference was developed. Therefore, it is expected to be used as fundamental data to promote the occurrence of S. impricatus during artificial cultivation, as it is possible to identify the stand where S. impricatus occurs indirectly.

• Land and Housing Review
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• v.15 no.2
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• pp.107-124
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• 2024

Based on Muan-gun, Jeollanam-do, this study explores how to mitigate the disappearance of rual areas. The study surveyed 95 young farmers in Muan-gun to assess their farming practices and the challenges they face. We further employ factor analysis and cluster analysis classify young farmers in Muan-gun, facilitating the identification of tailored policies or initiatives aimed at fostering and supporting young farmers. The results are summarized as follows. First, Muan County does not have any ordinances or original projects specifically designed to support young farmers. Second, the succession rate of farmland among young farmers in Muan County is 41.1%, which is comparable to the national rate of 43.7%. This indicates that approximately 40% of young farmers in Korea have inherited farmland, a critical foundation for agricultural activities. Third, despite accumulating farming experience, young farmers have not seen any improvement in local living conditions, and rather their difficulties have intensified. Fourth, this study conducted a factor analysis using 21 variables, resulting in the selection of seven common factors for cluster analysis. Consequently, young farmers in Muan County were categorized into three groups. The multinomial logit analysis revealed that the typology of young farmers is influenced by indicators such as cultivated area, farming experience, demand for smart farms, farm income, and farming type (rice cultivation or other). Therefore, to attract young farmers and prevent the decline of rural areas, policy efforts should focus on minimizing entry barriers to farming infrastructure, such as access to farmland, and improving local settlement conditions.