• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.129-129
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• 2022

The production area of Italian ryegrass feed is gradually increasing and labor-saving technologies are being developed. If sowing and fertilization are carried out agricultural drones, working hours and labor are reduced. The purpose of this study is to suggest an appropriate seedling amount for feed production by drone spreading of Italian ryegrass in spring. In addition, we would like to review the productivity of the drone seeding machine that is being developed by Rural Development Administration(RDA) of Korea. Italian ryegrass was sown by a drone in February at the NICS located in Gyehwa-hwa, Jeollabuk-do, South Korea. In Experiment 1, 50kg/ha, 60, 70, and 80 seeding rates were sown with a horizontal spreader drone. In Experiment 2, uniform spreaders type drone and horizontal spreader type were sown with the same seeding amount and compared. The drone was sown using the AF-52 aircraft. The higher the seeding amount, the higher the emergence rate. As the seeding amount increased, the plant length increased, but the number of tillers per individual decreased. The dry matter weight of the feed was the highest at 1,326kg/10a at the seeding rate of 70kg/ha, and decreased by 20.5% at the seeding rate of 80kg/ha. The coverage ratio was the highest at 96 at the seeding rate of 70kg/ha, which was the most advantageous for spring sowing. In the comparative experiment according to the spreader type, the uniform spreader had a high emergence rate per unit area. When the uniform spreader was used, the dry matter weight of the feed was 17% higher than that of the horizontal one, and the coverage was about 5% higher.

• Clinical and Experimental Vaccine Research
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• v.12 no.3
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• pp.179-192
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• 2023

The world has watched the emergence of numerous animal viruses that may threaten animal health which were added to the perpetual growing list of animal pathogens. This emergence drew the attention of the experts and animal health groups to the fact that it has become necessary to work on vaccine development. The current review aims to explore the perspective vaccines for emerging viral diseases in farm animals. This aim was fulfilled by focusing on modern technologies as well as next generation vaccines that have been introduced in the field of vaccines, either in clinical developments pending approval, or have already come to light and have been applied to animals with acceptable results such as viral-vectored vaccines, virus-like particles, and messenger RNA-based platforms. Besides, it shed the light on the importance of differentiation of infected from vaccinated animals technology in eradication programs of emerging viral diseases. The new science of nanomaterials was explored to elucidate its role in vaccinology. Finally, the role of Bioinformatics or Vaccinomics and its assist in vaccine designing and developments were discussed. The reviewing of the published manuscripts concluded that the use of conventional vaccines is considered an out-of-date approach in eliminating emerging diseases. However, these types of vaccines are considered the suitable plan especially in countries with few resources and capabilities. Piloted vaccines that rely on genetic-based technologies with continuous analyses of current viruses should be the aim of future vaccinology. Smart genomics of emerging viruses will be the gateway to choosing appropriate vaccines, regardless of the evolutionary rates of viruses.

• Korean Journal of Weed Science
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• v.18 no.2
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• pp.146-153
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• 1998

This experiment was conducted to clarify the characteristics of germination and emergence of Panicum dichotomiflorum which is a noxious weed species in direct-seeded rice field. P. dichotomiflorum was planted with several treatments such as different depths of irrigation to verifiy the ecological habits of seedling emergence and growth. In order to know the germination characteristics, Panicum dichotomiflorum seeds, pretreated with low-temperature($4^{\circ}C$) stratification for breaking the dormancy, were germinated under different temperature regimes and water potentials. Germination rates of P. dichotomiflorum was increased from 0% of dormant seed to 1%, 35% and 44% by stratification for 21, 28 and 42 days, respectively. Two dominant weed species in directseeded rice fields, Echinochloa crus-galli and Panicum dichotomitlorum, showed different germination habit under different temperature regimes. Echinochloa crus-galli showed more higher germination rate than Panicum dichotomiflorum at relatively low temperature regime(20/$10^{\circ}C$). Both species germinated faster at 30/$20^{\circ}C$ than at 20/$10^{\circ}C$. When the water potential was lowered, germination of Panicum dichotomiflorum was reduced more drastically than Echinochloa crus-galli. The critical water potential for germination of P. dichotomiflorum was -0.7MPa but Echinochloa crus-galli was affected slightly by the same water potential. The results showed that Echinochloa crus-galli can germinate under more wide range of soil water potential than Panicum dichotomiflorum. Emergence of P. dichotomiflorum was highly affected by irrigation depth and the level of water table. When the depth of irrigation water was increased, emergence of P. dichotomiflorum was dragged and emergence rate showed significant difference under the irrigation depth deeper than 6cm. The maximum depth of irrigation water for survival of Panicum dichotomiflorum seedling was 9cm.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.3
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• pp.169-172
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• 2003

Intact seeds of burcucumber (Sicyos angulatus L.) are not nearly germinated so that the farmers remove their arils before sowing. The study was carried out to measure the effort of aging, chilling, washing, chemical treatment, drying, and their sequential treatments on the germination of ones with arils and the seedling emergence. The seeds extruding over 1mm of their radicles and the seedlings with fully expanded cotyledons were counted daily for calculating the germination and the seedling emergence rates. Seedcoat softening using 10% NaOH solution somewhat enhanced their germination rate of the intact seeds harvested in the current year, but aging treatment done on 6 days at $45^{\circ}C$ after NaOH treatment increased the germination rate more than only NaOH treatment. A day washing after the NaOH treatment and a day chilling after the washing increasingly elevated the rates as well. Irrigation of 0.2% $\textrm{KNO}_3$ solution, moreover, showed the greatest germination rate of the priming treatments done during all the 7 day chilling. Drying the seeds after the combined treatment of chilling and priming more inclined the germination rate than nondrying ones, but red light treated during 24 hour desiccation was more effective in the germination rate increment than dark condition. The seeds done the sequential treatments of aging, NaOH, washing, combining chilling and priming and drying under red light illumination were germinated up to 80% but seedlings were emerged to 60%, lower than ones removed their arils.

• Korean journal of applied entomology
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• v.44 no.1 s.138
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• pp.43-50
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• 2005

Parasitism of the egg parasitoid, Trichogramma evanescens, to its main host insect, the Asian corn borer, Ostrinia furnacalis in Korea was compared with that of T. ostriniae that is the dominant species in China on the same host insect. Parasitoid adults of both species emerged more than 50 percent within 4 hours after lights-on in 16L/8D photo period regime and showed a circadian rhythm of emergence. The developmental period from oviposition to emergence in both parasitoids was ca. 11 days and there were no significant differences between the two species and between female and male of each species, either. Both species also showed superparasitism even when the parasitic rates in one egg mass were below 100 percent. Both species oviposited by 5 days after emergence, and maximum longevities of each female adult of both species were 8 day for T. evanescens and 6 day for T. ostriniae. The total number of eggs parasitized by T. evanescens was ca. 38 eggs and ca. 31 eggs by T. ostriniae. Newly emerged female parasitoid laid eggs on about $50\%$ of the host insect egg mass, and the parasitism decreased with the adult age of egg parasitoids in both species. The sex ratio of two species was female-biased about $80\%$.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.186-186
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• 2017

Relay intercropping system of direct seeded rice and winter cereal is labor saving cultivation and has high land use efficiency in Japan. In this system, rice seeds are direct seeded into inter-row space of winter cereals (wheat or barley) in March or April. If the direct seeding of rice is conducted before stem elongation phase or using suitable seeder, these are little effect to yield of winter cereals. Though the seeds are generally thiuram treated, it's a matter that seedling establishment rate (SER) of direct seeded rice is low and unstable. The cause of low SER has not been revealed. In present study, with the aim to reveal causes of low SER, we conducted experiments and investigated the SER, and analyzed some factors that might affect SER. Experiment1: In 2015, 2016, we buried rice seeds underground, and investigated the transition of the seed survival rates (SSR). Seeds were thiuram-treated or non-treated. In 2 periods, SSR of thiuram-treated seeds were significantly higher than non-treated seeds. In 2016, thiuram-treated seeds were high in SSR (almost 75%) at April 30th, but low SER (10~27%) after harvest of winter cereals. Therefore, almost all of seed death might have been happen after germination. Analysis 1: We investigated the SER and cultivation conditions in Ibaraki pref. for several years. Meteorological factors were referred from the nearest point of AMeDAS. From mean temperature (MT) among 5days after and before the day, we divided the period of seeding ~June 20 to phase1~4. We defined each phase as below; Phase1: $MT{\leq}10^{\circ}C$, Phase2: $10^{\circ}C<MT{\leq}15^{\circ}C$, Phase3:$15^{\circ}C<MT{\leq}20^{\circ}C$, Phase4: $MT>20^{\circ}C$. We analyzed the correlation of SER and meteorological factors by each phase. Total number of days in phase 1~4 was significantly negative correlated with SER. In phase1, total rain fall and number of soil wetting days were significantly negative correlated with SER. In phase2~4, only MT was significantly positive correlated with SER. This result suggested that rainfalls in phase1 declined seed vigor to emergence from soil surface, by repeated water absorption and re-dry. From these present studies, it was suggested that one of factors of low SER of direct seeded rice in relay intercropping system is changing of water condition by rainfalls in phase1 ($MT{\leq}10^{\circ}C$). To improve SER, it's necessary to consider something seed treatments such as prevent water absorption during phase1. However, 58~60% of seeds seemed to die during May. It's suggested that, if seeds are thiuram treated, almost all of seeds can germinate underground, but the seed vigor to emergence from soil surface are insufficient. Further studies are needed to reveal the rest causes that is happening during emergence from soil surface.

• Korean Journal of Ecology and Environment
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• v.54 no.4
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• pp.334-345
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• 2021

The present study investigated the effect of global warming on germination and initial growth across six deciduous oak species (Quercus mongolica, Q. variabilis, Q. serrata, Q. dentata, Q. aliena, and Q. acutissima), which are the dominant tree species in Korea forest ecosystems. Seeds were sown in climate change treatments, with temperatures higher than those of the control (approximately 3.0℃ higher), and CO₂ concentrations higher than those of the control (approximately 2-fold higher). Initial growth in each species was measured every two weeks. Initial growth was more rapid in all oak species at the time of root and shoot emergence under high temperature and CO₂ treatments than in the control group. Leaf emergence in Q. mongolica, Q. variabilis, and Q. serrata occurred earlier under the climate change treatments than under the control. Root length increased significantly in Q. mongolica, Q. variabilis, and Q. dentata under the climate change treatments when compared to under the control. However, Q. aliena and Q. serrata exhibited a contrasting trends, and no significant difference was observed between the species and Q. acutissima. Shoot length increased significantly in Q. aliena under climate change treatments when compared to under the control but decreased in Q. aliena. In addition, no significant difference was observed in shoot length among Q. mongolica, Q. dentata, and Q. acutissima. The results showed that climate change treatments facilitated early growth, rapid emergence from the ground, leaf development, and enhanced belowground growth in Q. mongolica. Conversely, Q. aliena exhibited the lowest aboveground and belowground growth under climate change treatments when compared to other oak species. Climate change treatments had the least impact on Q. acutissima considering the insignificant differences observed in initial growth rates under climate change treatment.

• Journal of The Korean Society of Grassland and Forage Science
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• v.12 no.1
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• pp.59-66
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• 1992

An experiment was conducted to determine the effects of seeding rates and nitrogen fertilization levels on the agronomic characteristics, nutritive value and forage yield of spring oat(Avena sativa L.). This experiment was undertaken over a period of 2 months from September to November, 1987. The results obtained are summarized as follows : Increased seeding rates of 120, 160 and 200kg/ha decreased emergence rates by 93.4, 71.4 and 70.6 %, respectively(P<0.05). Tillering was decreased by higher seeding rates(P<0.05) and that of 120kg/ha of seeding rate with 200kg/ha of nitrogen fertilization level was highest by 3.3. Among three seeding rates, tillering of 200 kg/ha of nitrogen fertilization level was lowest by 2.1. Leaf width was influenced by seeding rates. When seeding rate was increased, narrow leaf width (P

• KDI Journal of Economic Policy
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• v.14 no.4
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• pp.27-49
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• 1992

This paper stresses the role of market fundamentals rather than bubbles in explaining Korea's recent experience of large fluctuations of stock and real estate prices. The bubble story that emphasizes the self-fulfilling prophecies of investors seems to be inappropriate to explain the recent changes of assets prices in Korea. Those who argue for bubble phenomenon in Korea tend to interpret the volatile movements of assets prices as some form of bubbles, but without implementing a rigorous test on the presence of bubbles. Even when some bubble tests are carried out, such studies exhibit various econometric problems in testing. More seriously, they suffer from the misspecification problems in setting up a market model. This paper has shown that Korea's recent changes in assets prices could be explained by changes in market fundamentals according to the emergence and the subsequent fading of 'three lows'. First, it tried to explain changes in assets prices by changes in such market fundamentals as real interest rates and economic growth. Second, it showed that the real estate prices overshoot when the liquidity and exchange rates change, using the two-sector general equilibrium portfolio balance model. It is argued that the rapid rise in real estate prices during 1986-89 stems from Yen's and Won's appreciation $vis-{\grave{a}}-vis$ the U.S. dollar and liquidity expansion (or decreases in real interest rates), while the downturn in real estate prices since 1990 is associated with Yen's and Won's depreciation $vis-{\grave{a}}-vis$ the U.S. dollar and rises in real interest rates in reflection of the excess demand for liquidity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.2
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• pp.113-119
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• 1989

In 1988 the tolerance of corn, sorghum, sorghum-sudangrass. and pearl millet hybrids to simazine and alachlor was tested in field during the growing season and pots during the summer and fall. In field and summer pot experiments(Exp.) the above mentioned four crops were tested at the ratios of simazine WP (50% ai, g/10a) ; alachlor EC (43.7% ai. ml/10a) of 130: 0, 100: 0, 70: 200, 0: 300 and 0: 400 and a sorghum hybrid was tested at 0, 50, 100, 200, 300, and 400ml/10a of alachlor and 70g/10a of simazine+ 200ml/10a of alachlor in fall pot Exp. In corn emergence rate, percent stand, plant height of seedlings, and dry matter(DM) yield were not affected by simazine and alachlor in all Exps. In sorghum and sorghum-sudangrass early growth and DM yield were not affected by simazine and alachlor in field Exp. In contrast, simazine reduced height and dry weight of seedlings slightly without any deterimental effects on emergence and survival rates. but alachlor reduced survival rate, plant height, and dry weight of seedlings significantly in summer pot Exp. In fall Exp. alachlor did not affect emergence rate of a sorghum hybrid, but survival rate, plant height, and dry weight of seedlings reduced with increased levels of alachlor when applied higher than 100ml/10a. In pearl millet simazine did not affect emergence rate, plant height, and DM yield in field, but reduced survival rate, plant height, and dry weight of seedlings in summer pot Exp. However, alachlor reduced DM yield significantly due to a lower percent stand even in the field. In summer pot Exp. although emeregence rate was slightly reduced, all seedlings were dead after emergence. Simazine did not control grasses such as Digitaria sanguinalis, Setaria viridis, Echinochloa crusgalli effectively, but controlled broadleaf weeds. Alachlor controlled all grasses, Porluraca oleracea, and Amaranthus mangostanus, but did not control Acalypha australis and Chenopodium album. A combination of simazine and alachlor controlled weeds more effectively than either simazine or alachlor alone.