• Journal of The Korean Society of Grassland and Forage Science
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• v.28 no.4
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• pp.315-322
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• 2008

This experiment was conducted to investigate the selection of regional double cropping system for production of organic forage in southern region of Korea. The species of forage crop used in this experiment were com, sorghum$\times$sudangrass hybrid and japanese millet for summer crops and rye and Italian. ryegrass for winter crops. In organic cultivation condition, sorghum$\times$sudangrass hybrid showed higher DM (dry matter) and TDN (total digestible nutrient) yield than that of com. Dry matter yield of com which cultivated in organic condition decreased to about 35% that of control because of weed. In winter crops, DM and TDN yield of rye is similar to that of Italian ryegrass. We could not find out the difference of nutrient value between each treatments. It means that the amount of nutrient is affected by DM productivity of each crop. The result of this study indicated that sorghum$\times$sudangrass hybrid (summer crop) and rye (winter crop), sorghum$\times$sudangrass hybrid (summer crop) and Italian ryegrass (winter crop) cropping system could be recommended as producing high yield of organic forage in southern region of Korea.

• Journal of The Korean Society of Grassland and Forage Science
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• v.25 no.2
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• pp.119-124
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• 2005

This study was conducted from March 21 to July 8 in 2004 at JeJu Island to investigate the influences of split nitrogen application times on creeping bentgrass vegetation. Nitrogen rate was 20 kg/10a and it was applied from once to 5 times. The result obtained were summarized as follows; plant height was getting longer as nitrogen was split applied from once to 5 times. So it was longest at 5 times split nitrogen application, but it was no significance from 4 to 5 times. Root length, Minolta SPAD-502 chlorophyll meter reading value, leave and root weight n[e directly proportional plant height response. Degree of land cover Iud density of creeping bentgrass increased as nitrogen was split applied from once to 5 times. But degree of land cover md density of reed decreased. The number of reed species on decreased as nitrogen was split applied from once to 5 times. Then ranking of the dominant weeds were Portulaca oleracea Polygonum hydropiper and Stellaria media (at once split time nitrogen application), Portulaca oleracea, Polygonum hydropiper and Digitaria adscendens (at 2 split times nitrogen application), Digitaria adscendens and Portulaca oleracea Polygonum hydropiper, (at 3 split times nitrogen application), Portulaca oleracea, Poa annua and Polygonum hydropiper (at 4 md 5 split times nitrogen application). These results indicate that the optimum frequency of split N applications is four times for growth of creeping bentgrass in volcanic ash soils of Jeju island.

• The Korean Journal of Pesticide Science
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• v.7 no.4
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• pp.248-257
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• 2003

The objective of this experiment was to search plant species with herbicidal activity in Korea. Two hundred native plants were collected and their methanol extracts were obtained. Herbicidal activity of methanol extracts were determined by seed bioassay using canola (Brassica napus L.) seedlings. Six plants such as Staphylea bumalda, Wistaria floribunda, Allium victorialis, Rumex crispus, Chionanthus retusa, and Ulmus parvifolia were highly herbicidal: their $GR_{50}$ values were < $1,000{\mu}g\;g^{-1}$. In addition, seventeen plants such as Galium spurium, Zelkova serrata, Campsis grandiflora, Eucommia ulmoides, Sorbus commixta, Deutzia glabrata, Cercis chinensis, Alnus hirsuta, Zanthoxylum schinifolium, Quercus acutissima, Robinia pseudoacacia, Gleditsia japonica, Kerria japonica, Ligustrum obtusifolium, Thuja orientalis, Chamaecyparis obtusa, and Pulsatilla koreana showed herbicidal activity: their $GR_{50}$ values were between 1,000 and $2,000{\mu}g\;g^{-1}$. However, 177 plants showed no herbicidal activity. Plants with herbicidal activity found in this study could be used for weed management and herbicidal compounds in such herbicidal plants could be used as lead compounds in the development of new herbicides.

• Korean Journal of Soil Science and Fertilizer
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• v.6 no.1
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• pp.9-16
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• 1973

In order to observe the effect of a continuous application of herbicides on the chemical properties of upland soil, samples were collected and analysed from a field experiment continuously applied with herbicides and from two pot experiments, one with a heavy dose and the other with a normal dose of herbicides, applied continuously. The soil samples were collected after three harvests of radish. The results of these analysis were summarized as follows; 1. Of herbicides, M.O., Lorox, 2, 4-D, Lasso, and P.C.P., the Lorox decreased soil pH and organic carbon content in soil and increased exchange and hydrolytic acids, and exchangeable potassium. The herbicide also showed an indication to decrease the exchangeable calcium, magnessium and sodium in soil. It seemed that such changes are mainly due to the indirect effect of Lorox or its metabolites, such as stimulating soil microorganisms, rather than direct chemical nature of them. 2. The other herbicides investigated in this study seemed to increase the organic carbon content in soil. 3. In addition, the continuous application of herbicides may result in an alteration of weed species in the field. All such facts might affect the properties of soil, which may call for a further detailed investigation having a set up of a long term experiment.

• Korean journal of applied entomology
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• v.53 no.4
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• pp.435-440
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• 2014

The number of Bemisia tabaci adults attracted to horseweed, thistle, red bean, cucumber, and tomato plants, as measured by the number stuck to yellow sticky traps, was investigated in a polyvinyl greenhouse for growing tomatoes using organic methods. The number was highest on cucumber plants in the early days of B. tabaci infestation, but was highest on horseweed overall. Of the eight species of beans tested, B. tabaci adults were most attracted to Ultari-Gangnang; however, beans were not effective trap plants for B. tabaci. Measurement of olfactory behavioral response using a four-choice olfactometer showed that B. tabaci adults preferred horseweed to cucumber, eggplant, or tomato. The developmental period of B. tabaci eggs and larvae was shorter at high temperature. At $30^{\circ}C$, the developmental period of eggs and larvae on horseweed were reduced approximately 0.5 and 1 day, respectively, compared to those on cucumber or tomato.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.325-325
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• 2017

In the 20th century, the average temperature of Korea has risen by $1.5^{\circ}C$, whereas it has risen by $0.6^{\circ}C$ globally. Few studies have investigated the effect of seeding date in hilly pastures on their growth characteristics and productivity. The purpose of this study was to elucidate the effect of seeding dates at a hilly pasture establishment on its growth characteristics and productivity caused by increasing temperatures in Korea. The experiments were conducted from 2014 to 2016 at Pyeongchang, South Korea, at an altitude 600-700 m above sea level. The composition of grass mixture was tall fescue, orchard grass, perennial ryegrass, Kentucky bluegrass, timothy, and white clover. Treatments comprised four seeding dates (August 13 and 27, and September 10 and 24). The establishment rate was lowest on September 24, resulting in only 20% establishment over the winter, and the proportion of weeds was highest on September 24 (58%). Early seedling growth before overwintering is a critical approach to ensure successful establishment of grassland. The main components were orchard grass and tall fescue on the early seeding date (August 13), and Kentucky bluegrass on the late seeding date (September 24). Late seeding increased the proportion of bare lands invaded by weed species, especially during second and third cutting periods. Early seeding date resulted in a progressive increase in biomass. Total annual production was significantly affected by the seeding date; lowest dry matter production was on September 24 ($2,441kg\;ha^{-1}$), whereas maximum dry matter yield was on August 27 ($6,608kg\;ha^{-1}$). The results of the study indicate that growth condition and productivity could be increased by early seeding, and seeding of grass in the Pyeongchang area should be completed before August 27. However, further studies are needed to determine the ideal seeding date at the hilly pasture establishment in Pyeongchang.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.4
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• pp.275-280
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• 2007

This experiment was conducted to investigate the selection of regional double cropping system for production of organic forage in middle part of Korea. The species of forage crop used in this experiment were corn, $sorghum\;{\times}\;sudangrass$ hybrid and japanese millet for summer crops and rye and Italian ryegrass for winter crops. $Sorghum\;{\times}\;sudangrass$ hybrid showed higher DM (dry matter) and TDN (total digestible nutrient) yield than that of corn. Dry matter yield of corn decreased to 56% that of control because of weed. In winter crops, DM and TDN yield of rye is higher than that of Italian ryegrass. Rye was more adequate to produce organic forage in middle part of Korea. We could not find out the difference of nutrient value between each treatments. It means that the amount of nutrient is affected by DM productivity of each crop. The result of this study indicated that $sorghum{\times}sudangrass$ hybrid (summer crop) and rye (winter crop) cropping system could be recommended as producing high yield of organic forage in middle part of Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.5
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• pp.564-570
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• 1997

Field experiments were carried out to investigate the effects of different residue treatment of vetch sward on soil improvement, rice growth and grain yield from 1995 to 1996. With Chinese milkvetch, pH, Ca, and Mg of paddy soil were increased in subsoil(10~20cm soil depth), and organic matter, P$_2$ $O_{5}$, and K were increased in top soil (0~10cm soil depth). Redox potential of the paddy soil with milkvetch residue was severely reduced at earlier flooding period, and recovered gradually as rice growth continued. Weeds were more abundant in the paddy with unchanged vetch stand. The most dominant weed species in the paddy soil with vetch sward residue was Echinochloa crus-galli, followed by Leersia japonica, Polygonum hydropiper in the order of abundance. Seedling establishment ratio of rice directly sown over vetch-sward was lower than in conventional tillage paddy(no-vetch, tilled) condition. Rice growth pattern, however, was not significantly affected by vetch sward treatments. The number of tillers per square meter and plant height at heading date were not significantly different among the vetch-sward treatments. Grain yield was the highest in plough of vetch vegetation, followed by conventional (no-vetch, tilled), live-mulching of vetch, vetch-removed, and vetch-desiccated by weedcide. The whole grain rice yield was the lowest in vetch-desiccated by weedcide.

• Journal of The Korean Society of Grassland and Forage Science
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• v.5 no.3
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• pp.191-195
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• 1985

This field experiment was undertaken to assess the effects of three levels of inclination ($10^{\circ},\;20^{\circ},\;and\;30^{\circ}$) and four rates of $N-P_2O_2-K_2O$ (O-O-O, 14-10-20, 28-25-25, and 42-40-40kg/10a) on establishment, forage yield and quality and botanical composition of new established mixed grass-clover sward. This first part is concerned with the forage yield, yield component and botanical composition. The results obtained after a two-year experiment are summarized as follows: 1. Dry matter yields of mixed grass-clover sward were greatly decreased by increasing the inclination grade of hilly pasture, whereas it of weeds was not significantly influenced. Comparing with weeds, the establishment of introduced pastures was relatively low with increasing the grade of inclination. 2. By increasing the NPK rate, the yields of grasses and mixed forages and the rate of introduced pastures were greatly increased at all grades of inclination, whereas the change in the weed yield was not significant. 3. There were the differenced in the forage yield and yield component, and efficiency of fertilizers by the grade of inclination, which indicated the necessity of different management on the selection of suitable grass species, seeding rate, amount of fertilizer application, and the methods of grassland establishment, management and utilization.

• Journal of Wetlands Research
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• v.21 no.1
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• pp.57-65
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• 2019

LID(Low Impact Development) facility classified as a social infrastructure can maintain landscape sustainability and functional sustainability through continuous maintenance and management. Since LID is a natural-based solution, the sustainability can be secured through the management of weeds, wastes and vegetation. The LID facility is distributed in the city and is an infrastructure that can be managed through citizen participation because of simple maintenance. Therefore, this study was conducted to investigate the maintenance factors affecting the sustainability of the LID facilities and to suggest measures for maintenance by investigating the participation of the peoples. The factors for landscape sustainability were derived to waste and weed management. Also the factors for functional sustainability were assessed to identification and management of dead bodies and selection of applicable soil and plant species. The citizens showed high agreement of more than 80% in the questionnaires on expanding and managing LID facilities, enacting LID ordinances, and participating in the national movement. The intention to participate in LID management linked to jobs was about 64%, indicating that LID could become a job for the vulnerable. Maintenance of the LID can easily be carried out by non-specialists, which can lead to citizen participation with low cost for each facility. The maintenance cost for citizen participation can be allocated from the social infrastructure management cost reduced by LID application of the local government and the social welfare budget of the central government.