• Korean Journal of Medicinal Crop Science
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• v.27 no.6
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• pp.397-403
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• 2019

Background: Oplopanax elatus is widely distributed at high altitudes (about 1,100 m) in China, Russia and Korea. It is hard to propagate, breed, and difficult to grow. Hence, it has been designated as a rare and endangered medicinal plant. A study was conducted to establish a system for large scale seedling production of Oplopanax elatus in vitro and to find the ideal environment for its seedling growth. Methods and Results: In this study, the explants produced under in vitro conditions during our previous study were grouped into three categories (under 10 mm, 10 mm - 30 mm and above 30 mm) based on plant height and were transferred to the growth-chamber and greenhouse for two weeks in each setting for acclimatization. The plantlet category of above 30 mm showed good performance, and was further evaluated under three acclimatization methods as follows: three different growth media (commercial soil, commercial soil + perlite, commercial soil + sand), four shading levels (0%, 50%, 70%, 90%) and four altitude levels (157 m, 218 m, 601 m, 870 m) in Gangwon province of South Korea. As results, O. elatus seedlings showed better growth characteristics at 870 m of altitude, 70% shading level and in the commercial soil compared to other treatments. Conclusions: The regenerated seedlings of Oplopanax elatus obtained through plant tissue culture would be advantageous for use in large scale seedling production systems paired with a good acclimation method. For obtaining optimal results, it is recommended that seedling be acclimatized in a high altitude environment.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.3
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• pp.286-291
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• 1997

This experiment was carried out to improve seedling emergence and establishment in paddy rice sown into puddled soil. Rice seed were coated with CaO$_2$, KNO$_3$ and acid sulphate soil. When coated seeds with CaO$_2$, KNO$_3$ and acid sulphate soil were sown into puddled soil, soil redox potential was increased and the period of oxidizing was longer in KNO$_3$ than that of any other soils. pH was higher in control than that of coated seeds with CaO$_2$, KNO$_3$ and acid sulphate soil. It seems that the coated seeds oxidize soil locally, thus prohibit soil reduction. Seedling emergence was improved by seed coating materials. Emergence date was 8 days after seeding(DAS) in CaO$_2$, 14 DAS in acid sulphate soil, 21 DAS in KNO$_3$ coated seed and 20 DAS in uncoated seed, respectively. Emergence rate was highest in CaO$_2$ coated seed(80％) followed by acid sulphate soil coated seed(61％), while control(46％) and KNO$_3$(42％) were very poor. This result would be interpreted as the difference in oxidizing power among coating agents ; CaO$_2$ and acid sulphate soil may oxidize weakly and shortly while KNO$_3$ may oxidize soil strongly and persistantly. Our results suggested that local oxidizing around rice seed sown into puddled soil enhanced seedling emergence and also found a possibility to promote seedling emergence with acid soil.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.4
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• pp.287-298
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• 2019

The aim of the present study was to compare the germination and seedling characteristics of rice varieties grown under various flooding conditions and different temperature and oxygen levels and to identify germplasm suitable for wet direct seeding. Three anaerobic germination tolerant (AGT) genotypes (PBR, WD3, KHO) and eleven Korean rice varieties (KVs) adapted for direct seeding were evaluated for seedling performance under different temperatures (15, 18, 21, and 24℃ ) and oxygen levels (Low, Normal, High). Compared with the KVs, the AGT genotypes (especially KHO and PBR) exhibited relatively high germination and survival rates and coleoptile and radical growth rates under low temperature and low oxygen conditions, thereby indicating their suitability for wet direct seeding. Among the KVs, 'Dongan,' 'Jungan,' and 'Cheongdam' rice exhibited the highest survival rates under low temperature and low oxygen conditions. Three-way ANOVA indicated that temperature had the greater effects on seedling characteristics (43.2-78.0%) than either oxygen level (15.4-37.5%) or genotype (2.0-29.8%) did. Therefore, in direct seeding cultivation, temperature was the most important environmental factor for seedling establishment.

• Journal of Practical Agriculture & Fisheries Research
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• v.3 no.1
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• pp.30-47
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• 2001

This research was performed to develope a stable direct seeding method in rice cultivation using by a direct seeder with soil application. A principle of this methodology was introduced from seeding nursery system of machine transplanting enable to increase high seeding establishment direct seeding method with soil application was high of 89-95% while that of water seeding was 68%. During seeding growth plant height was ralatively small but seeding health was high. A total soil consumption of this methodology was 145kg/10a in dirll seeding and 26kg/10a in hill seeding respectively, there was 100% erected in direct seeding with soil application while water seeding was 45% in erected seeding stand. In direct seeding method with soil application total carbohydrate content was higher than that of water seeding. This machine was manufactured to attach and/or detach to a machine transplanter with riding type and machine cultivator with multipurpose. In the farmer's demonstrated rice field this method was well performed like machine transplanting in terms of rice growth and development. There was highly cost reduction for rice production like other direct seeding methods.

• 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.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.1
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• pp.50-56
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• 2016

Direct seeding of sorghum (Sorghum bicolor L. Moench) has a problem of low yield including poor establishment. This poor establishment results from poor quality seed, poor seedbed preparation, seedling pests, poor sowing technique and high soil temperature. This study sought to establish the age at which sorghum seedlings can be transplanted with minimal effects on grain yield. Transplants were raised in 128 nursery tray pot. Five seedling ages were established by transplanting at 10 (T10), 15 (T15), 20 (T20), 25 (T25) and 30 (T30) days after planting (DAP). The treatment combinations were arranged in a randomized complete block design and replicated three times with an individual plot size of $6{\times}5m^2$. Each plot had five ridges with a planting space of $0.60{\times}0.20m^2$ at one plants per stand. Results showed that seedling age on transplanting significantly affected growths and yields to sorghum after transplanting. Plant heights and diameters of transplants at T15 were longer than the other transplants. Conclusively, The advantages of this practice were better control of crop density and greater yields; either to fill gaps after emerging and thinning of crops or to compensate for a growth period that was too short for a complete crop cycle.

• Korean Journal of Organic Agriculture
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• v.20 no.4
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• pp.475-490
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• 2012

Since 1997, Korean Ministry of Knowledge Economy and Ministry of Environment have established data on some 400 basic raw and subsidiary materials and process like energy, petro-chemical, steel, cement, glass, paper, construction materials, transportation, recycling and disposal etc by initiating establishment of LCI database. Regarding agriculture, Rural Development Administration has conducted establishment of LCI database for major farm products like rice, barley, beans, cabbage and radish etc from 2009, and released that they would establish LCI database for 50 items until 2020 later on. The domestic LCI database for seeds, seedling, agrochemical, inorganic, fertilizer and organic fertilizer etc is only at initial stage of establishment, so overseas LCI databases are brought and being used. However, since the domestic and overseas natural environments differ, they fall behind in reliability. Therefore, this study has the purpose to select organic farming materials, survey the production process for various types of organic farming materials and establish LCI database for the effects of greenhouse gas emitted by each crop during the process. As for selecting methods, in this study organic farming materials were selected in the method of direct observation of material and bottom-up method a survey method with focus on the organic farming materials admitted into rice production. For the basic unit of carbon emission amount by the production of 1kg of organic farming material, the software PASS 4.1.1 developed by Korea Accreditation Board under Ministry of Knowledge Economy was used. The study had the goal to ultimately provide basic unit to calculate carbon emission amount in executing many institutions like goal management system and carbon performance display system etc in agricultural sector to be conducted later on. As a result, emission basic units per 1kg of production were calculated to be 0.04968kg-$CO_2$ for oystershells, 0.004692kg-$CO_2$ for expanded rice hull, and 1.029kg-$CO_2$ for bordeaux mixture liquid.

• Journal of The Korean Society of Grassland and Forage Science
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• v.6 no.1
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• pp.1-5
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• 1986

In series of pasture improvement studies with herbicides on nonarable hilly area, the effects of different cutting intervals (10, 20, 30 and 40 days) after glyphosate (2.9 kg/ha active ingredient) application on establishment and development of surface-sown orchardgrass(Dactylis glomerata L.) and ladino clover (Trifolium repens L.) was measured during 1983-1984. The cutting intervals of the existing shrubs after glyphosate application had no differential effect on establishment, seedling vigor, dry matter yield of surface-sown pasture species and botanical composition of improved pasture. Results showed that good control of the existing shrubs for surface-sown pasture species can be achieved by cutting the shrubs from 10 to 40 days after glyphosate application.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.1009-1020
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• 1996

Direct-seeded rice can have comparable yield with transplanted rice if its inherent problems can be solved. It is a labor-saving technology and can significantly reduce production cost because seedling nursery , pulling , and transplanting are omitted. Turnaround time between cropping is reduced hence the possibility of a third annual crop. But direct-seeded rice is very vulnerable to pest attack (by birds, rats, and golden snails), desiccation, weed infestation, and prone to lodging resulting to unstable crop establishment and inconsistent yield. These problems can be solved by anaerobic seeding (sowing pre-germinated seeds under the soil). It requires precise seed placement into the soil to optimize its benefits. We developed a four-row anaerobic direct seeder (US $ 200 commercial price) for this purpose . It consist of a structural framework mounted with a drum -hopper metering device, flotation type drivewheels, spring-loaded and adjustable furrow closers, and furrow open rs, and a plastic rainguard. It can sow in line pre-germinated seeds into the soil thus permitting the use of mechanical weeders for a chemical-free weed control. Its performance was comparable with the Japanese two-row anaerobic seeder (costing US$400) in terms of seed placement and crop establishment. It was tested with five cultivars. Seeding rate varied from 38 kg/ha to 80kg/ha. Crop establishment ranged from 64 to 99 percent while grain yield varied from 3.0 t/ha to 5.4t/ha. A six-row anaerobic seeder was also developed and adapted to a powertiller for increased capacity , field efficiency , and easier operation. The anaerobic seeder is useful to farmers shifting to direct seeding to reduce rice production cost and to researchers conducting agronomic studies in direct-seeded rice. Blueprint of the machine is available free of charge from IRRI.

• Journal of Life Science
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• v.28 no.7
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• pp.772-777
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• 2018

To understand the adaptability of Leymus chinensis forage grass to environmental stresses, we analyzed the $H_2O_2$ scavenging activity based on several antioxidant enzymes and total phenolics content, including peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT), in shoots and roots subjected to salt and dehydration stresses during seedling growth. After NaCl or PEG treatment, plants showed reduced seedling growth under over 200 mM NaCl or 30% PEG treatment condition in shoots and roots compared with the control condition. In addition, plants showed high enzymatic activity of CAT in the shoots, whereas they exhibited high activity levels of APX and POD in the roots in both the NaCl and PEG treatment conditions. These results seem to indicate that Leymus chinensis seedlings responding to salt and dehydration stresses during initial growth is associated with enhanced activity of $H_2O_2$ scavenging antioxidant enzymes in the shoots or roots. The plants also showed high levels of total phenolics under NaCl treatment, with a high concentration in both the shoots and roots. Our results showed that the induced activity patterns of APX in the roots and CAT in the shoots indicate that low $H_2O_2$ levels were mainly maintained through tissue-specific redox homeostasis involving enzymes such as APX and CAT during salt and dehydration stresses. This study highlights the importance of antioxidant enzymes in the establishment of Leymus chinensis seedlings under high salinity conditions, such as typical desertification.