• The Journal of Natural Sciences
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• v.5 no.2
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• pp.49-62
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• 1992

This study was carried out to investigate the emergence, growth and yield components in rice inassoccation with Several cultivation methods direct sowing flooded paddy field(DSF), direct sowing by airplane(DSA), direct sowing in dry paddy field(DSD), 8days seedling planting(8DS), and 35days seedlingplanting(35DS). Also this study was attempeted to know the effects of calcium peroxide on germinationand early growth of rice under different soil conditions, seeding depth, application of organic matter,indirect sowing flooded paddy field.1. Rate of emergence was 73% in DSF, 70% in DSA, 62% in DSD, respectively, under the different cultivation method of rice in reclaimed paddy field.2. Degree of lodging in relation to cultivation was 5 at both DSF and DSA, 3 at DSD, 2 at both 8DS and 35DS respectively.3. Maximum tiller number was 568 per m2 at DSF and 527 at DSA. Heating was delayed for 4 days at DSF, 8 days at DSD and 2 days at 8DS as comparison with that at 35DS.4. Yield was higher 1% to 3% at DSF than that at DSA and DSD while decreased by 12% as compared with that of seedling planting.5. Total dry weight of seedling was decreased by 57% at 8DS, 60% at DSF 63% at DSD, respectively, under 0.3% of salinity. Ratio of decreasing in dry weight was higher with high salinity.6. The amount of O2 released was recorded highest to 2 to 3days after irrigatition, thereafter remaining constant to 10 days after irrigatition.7. The optimum coating amount of calcium peroxide for germination was a half of rice seed weight with 1 cm sowing depth and one-fold with 2-cm sowing depth when rice straw was not applied. With rice straw applied, on the other hand, the amount of peroxide was one-fold with 1-cm sowing depth. It was found that, under the condition of applied 600kg/10a, of 2-cm soil depth with rice straw calcium peroxide coating had no effect on emergence of rice seedling.8. In reclaimed paddy field, lodging degree was 7 with direct sowing by machine and 9 with direct sowing by hand.9. Yield was increased by 5% by applying rice straw with direct sowing by machine.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.4
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• pp.287-294
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• 2006

Germination and early elongation of rice after germination were investigated in anoxic air treatment, nitric oxide gas treatment, and six concentrations of mercuric chloride solutions to determine the effects of limited oxygen environment, nitric oxide, and inhibited water flux through cell membrane in $17^{\circ}C$. Anoxic air treatment affected germination of tested six varieties very little. However root elongation rates were severely inhibited while shoot growth was affected less. Reductions in shoot and root elongations demonstrated genotypic variations. Nitric oxide delayed the germination of rice even though it didn't affect the final percent germination. Elongations of root and shoot were inhibited in nitric oxide treatment. The inhibitor effect of nitric oxide on the shoot elongation of rice was less severe, while nitric oxide completely inhibited the root emergence of rice. Concentrations of $HgCl_2$ greater than $300{\mu}M$ dramatically reduced the rate and percentage of germination when compared to distilled water treatment. The reduced percent germination showed the greatest variation among rice varieties in $500{\mu}M$ solution of mercuric chloride. Ansanbyeo, Jinheung, and Odaebyeo were affected less by $HgCl_2$, Nonganbyeo and Sangmibyeo were intermediate, and the germination of Andabyeo was greatly reduced by $HgCl_2$. Root elongation of germinated rice seedlings was more sensitive to oxygen deficits, nitric oxide, and $HgCl_2$ treatments than germination and shoot elongation. In conclusion, poor seedling establishment of rice sown in flooded paddy soils, in which the oxygen supply to the seeds is restricted, appears to the result of limited root elongation rate.

• Korean Journal of Organic Agriculture
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• v.16 no.3
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• pp.299-308
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• 2008

In this study, the effect of commercial organic growth medium amended with different ratios of vermicast on the growth of rice seedlings. The amended ratios of vermicast were 0% (control), 5%, 10%, 20% and 40%, respectively. A bioassay with two rice varieties (Chucheng and Black) was conducted to assesses the amendment effect of vermicast on the seedling growth in two potting methods. In potting treatment, the Chucheng variety with late maturity showed significantly higher values on growth parameters excepted root weight (RW) up to 20% and Black variety with early maturity up to 10% amended with vermicast, respectively. In floor layering treatment, all of the growth parameters significantly increased up to 5% amended with vermicast in both rice variety. The seedling growth of rice in floor layering treatment attained the highest values at lower amended ratios of vermicast than those of potting treated only, it may correspond with increased uptake of nutrient by elongated root grown under the layering amendment of vermicast. Vermicasts can be used as soil amendments or components of plant growth medium for seeding organic agriculture.

• Korean Journal of Weed Science
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• v.15 no.2
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• pp.115-120
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• 1995

This experiment was conducted in the paddy field to investigate the influence of bensulfuron (methyl-2-[[[[[(4,6-dimethoxypyrimidin-2-yl)amino]carbonyl]amino]sulfonil]methyl]benzoate)+butachlor (N-(butoxymethyl)-2-chloro-2',6'-diethyl acetanilide) and bensulfuron+mefenacet(2-(1,3-benzothiazol-2-yloxy)-N-methylacetanilide) for seedling age of rice with Dongjinbyeo of medium-late-maturing variety, Hwaseongbyeo of medium-maturing variety and Namwonbyeo of early-maturing variety. Two herbicide applications interfered with the early growth of all rice varieties, the root was especially damaged more than the shoot. The phytotoxicity of bensulfuron+butachlor and bensulfuron+mefenacet was not significant statistically and the phytotoxicity of these herbicides for seedling age was apt to be similar, also. Twenty and 35days seedlings of Dongjinbyeo and Hawseongbyeo had more growth amount than 8days seedlings, but Namwonbyeo had opposite trend. The number of maximum tillers in the plots applied herbicides were fewer than untreated control but, the percentage of productive tillers was higher than those. Heading date for Namwonbyeo was delayed 2, 1-2 and 2-3days on 35, 20 and 8days seedlings by herbicide application, respectively.

• Korean Journal of Weed Science
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• v.12 no.3
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• pp.292-308
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• 1992

Recently agricultural situations are being placed in unfavourable socio-economic environment as followed by rapid decrease of rural population, poor labor quality and high wages of rural society due to high speedy industrialization of social structure in Korea. In addition to those circumstances, under the UR system to be expected in the early future, free trade of agricultural products will be faced inevitably in Korea. Practically prices of rice as a principle food in this country are expensive about three times compared to those of foreign rice markets, and so how to increase the international competitiveness and food supplies are important problems to be solved rapidly. Accordingly an urgent goal is reduction of agricultural production cost by the improvement of labour productivity as a labour saving and cost down cultivation methods as the direct seeding cultivation in rice. But there are many problems in the direct seeded rice cultivation. The important things to be improved in that cultivation are development of rice varieties with lodging tolerance, effective seedling stand, weed control, irrigation management and fertilizing and so on. Moreover agricultural basis as irrigation facilities, land consolidation and farm machineries must be improved for the stability of rice cultivation in the future.

• Proceedings of the Korean Society of Crop Science Conference
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• 2001.09a
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• pp.102-103
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• 2001

• Korean Journal of Environmental Agriculture
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• v.25 no.3
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• pp.268-275
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• 2006

ALA (5-aminolevulinic acid) has been proposed as a tetrapyrrole-dependent photodynamic herbicide by the action of the protoporphyrinogen IX oxidase (Protox IX). A study was conducted to determine photodynamic herbicidal effect of ALA on seedling growth of rice (Oryza sativa L.) and barnyard grass (Echinochloa crus-galli Beauv. var. oryzicola Ohwi) under dry and wet conditions. ALA effect on early plant growth of rice and barnyardgrass was greatly concentration dependant, suggesting that it promotes plant growth at very low concentration and inhibits at high concentration. No significant difference in herbicidal activity of biologically and synthetically produced ALAs on plant lengths of test plants was observed ALA exhibited significant photodynamic activity regardless of PSDIP and its duration. Significant shoot growth inhibition by ALA soaking treatment exhibited apparently, indicating that ALA absorbed through root system was translocated into shoot part of plants. ALA reduced plant heights of rice and barnyardgrass seedlings by 6% and 27%, respectively, showing more tolerant to ALA in rice under wet condition. Leaf thickness was reduced markedly by ALA with increasing of ALA concentration, due to mainly membrane destruction and severe loss of turgidity in mesophyll cells, although the epidermal was little affected. It was observed that photodynamic herbicidal activity of ALA applied by pre-and post-emergence application exhibited differently on plant species, and that the activity of ALA against susceptible plants was highly correlated with growing condition.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.255-263
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• 2020

In this study, we evaluated the salinity tolerance of five forage rice cultivars (Mogwoo, Mogyang, Miwoo, Jowoo, and Yeongwoo) with respect to germination, seedling growth, productivity, and feed values in a reclaimed paddy field in Muan, Korea. We found that the cultivars Mogwoo, Miwoo, Jowoo, and Yeongwoo showed normal germination and seedling growth, even at saline concentrations of between 0.1% and 0.5%, whereas in contrast, there were significant reductions in the germination and seedling growth of Mokyang with an increase in salt concentration. Among the five cultivars assessed, the seedling growth of Mogwoo and Yeongwoo was relatively higher at different salt concentrations in hydroponic and sand cultivation. Furthermore, cultivation of the five cultivars in the reclaimed paddy field with an initial salt concentration of 0.3% revealed that Yeongwoo was relatively superior in terms of yield and feed value. In conclusion, the germination and early growth of Yeongwoo were relatively good at high salt concentrations, and the yield and forage value of this cultivar in a reclaimed paddy field were also relatively superior to those of the other assessed varieties.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.3
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• pp.135-138
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• 2003

Appropriate allocation of personal and financial resources of a research organization is important for the successful accomplishment of its goals. Direct-seeding of rice is a technology compatible with sustainable agriculturer and much research on the technology has been carried out in the research institutes of Rural Development Adminstration (RDA). We analyzed, with a special interest in research on rice direct-seeding technology, patterns of resource allocation in RDA by technology to evaluate congruency levels in research resource allocation. Research on direct-seeding technology had been focused on its fundamental field in the past. However, research to solve the practical difficulties encountered by farmers such as those in seedling establishment weed control, and water management practices, has been increased in recent years. Research resource allocation had largely been made to the projects for variety and seeding-technology development in the early years, however, allocation to the projects for the fertilization, weed control, and water management fields has been increased in recent years. Allocation of resources to the projects in soil management and seedling establishment categories was decreased, indicating that difficulties encountered by farmers in these fields were mostly solved. High congruency between economic outcome of research and allocation of resources by technology categories indicates a rational allocation of resources for research on direct-seeding of vice in RDA.

• Korean Journal of Weed Science
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• v.16 no.3
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• pp.181-186
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• 1996

This experiment was conducted at National Yeongnam Agricultural Experiment Station in 1995 to identify effects of early flooding in dry seeded rice on rice growth and weed occurrence. The early flooding of emergence date and the 2-leaf stage were not differed significantly on seedling stand, seedling growth of rice and plant characteristics associated with lodging compared to flooding of the 4-leaf stage. However, weed occurrence resulted in 39-61% suppression. Most predominant weed regardless of flooding times was Echinochloa crus-galli, followed by Aneilema japonicum. The Aneilema japonicum, in general, was higher occurrence with earlier flooding, while dry land weeds such as Digitaria sanguinalis, Stellaria alsine etc. reduced. Grain yield of early flooding at emergence date and the 2-leaf stage was higher by 2-5% than that of the 4-leaf stage due to better grain filling ratio and heavier 1,000 grain weight.