• Korean Journal of Weed Science
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• v.17 no.3
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• pp.281-287
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• 1997

Growth and anatomical responses of rice and barnyardgrass(Echinochloa crus-galli) to oxyfluorfen were examined under various growing conditions in a greenhouse. With foliar application at 0.08kg ai/ha 7 days after seeding or transplanting, oxyfluorfen completely reduced the shoot and root growth of barnyardgrass under all growing conditions. However, oxyfluorfen reduced the growth of direct seeded and transplanted rice by 0~64% and 0~12%, respectively. Phytotoxic effect on rice growth, with respect to plant height and shoot fresh weight, was more pronounced under water(53~63%) than under dry-condition(16~33%), and in broadcast-seeded(34~62%) than in drill-seeded rice(16~33%). Anatomical changes of epidermal and vascular bundle sheath cells of rice leaves were not induced by oxyfluorfen, but mesophyll cells were partially ruptured and total leaf thickness was reduced. Oxyfluorfen, however, constricted and ruptured mesophyll and vascular bundle sheath cells and severely reduced leaf thickness of barnyardgrass under all growing conditions examined. These anatomical changes were more severe under dry- than under water-seeded condition.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.4
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• pp.305-309
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• 1991

This experiment was conducted to investigate the effect of shattered grain by combine harvesting at the previous year on rice plant emergence at different planting methods and plant characteristics, The results are follows : Combine harvesting greatly influence on shattered grain of Samgangbyeo as Tongil variety (49.5kg/10a) compared to that of Nagdongbyeo as Japonica variety(27.8kg/10a), while Nagdong-byeo showed higher germination rate than Samgangbyeo, whether transplanted and direct seeded. Emergence of volunteer and seed mixture were lower in transplanted than in direct seeded. In variety test. Japonica variety showed higher emergence of volunteer rice and seed mixture than Tongil variety. Generally, no significant difference in yield components were observed with different varieties by the volunteer rice. But the volunteer rice caused by combine harvesting decreased culm length, panicle length, spikelet number, panicle number and ripening ratio. except l000-grain weights.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.4
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• pp.232-236
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• 2000

To obtain a basic information on the development of effective control strategies for weedy rice in direct seeding rice cultivation, occurrence patterns of weedy rice as influenced by different cultural practices such as cultivation method, water management, seeding time, and tillage were investigated in field or pot experiments. High occurrence of weedy rice was observed in a continuous direct seeding paddy field as compared to machine transplanted one. Based on the percent of weedy rice panicle over three years trial, high ridged dry seeding was highest with 36.9%, followed by wet seeding with 30.9%, water seeding with 14.6% and machine transplanting rice with 0.8%, indicating 97.8% reduction in weedy rice occurrence by machine transplanting rice as compared with high ridged dry seeding. Germination of weedy rice was promoted to 83-94 % when rice panicle was flooded from September 30 to October 10 for 6 days and 74-88% for 9 days on October 20. Weedy rice occurrence was also substantially reduced by delayed seeding on June 10 and intensive tillage. The results suggest that machine transplanting rice be more effective cultural practice than flooding treatment, delayed seeding and intensive tillage when weedy rice problem occurs in direct seeded paddy field.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.1
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• pp.32-37
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• 1998

The objective of this study was to analyze lodging-related traits using different cultivars from Korea, Japan, and the U.S. in direct seeded rice on dry paddy field. Stem diameter and culm wall thickness were highest in 'Caloro' followed by 'Nongan', 'M202', and 'Calrose'. All the U.S. cultivars were higher than the others in stem diameter and culm wall thickness. These two traits were important with regard to lodging. The highest breaking strength (1442g) was observed in Caloro. 'Gancheoek', 'Dongjin', and transplanted 'Hatsuboshi' showed more than 1000g in breaking strength. Lodging index was lowest in Hatsuboshi followed by Nongan and Gancheok. Even though breaking strength of the U.S. cultivars was higher than others, their lodging index values were high. There were no statistically significant differences in starch content. However, Calrose, Caloro, Dongjin, and Koshihikari were relatively higher than others in starch content. Positive correlations were found between culm base weight, lignin and breaking strength. High contents of lignin and cellulose were observed in Nongan, transplanted Hatsuboshi, Calrose, and Caloro. Traits such as stem diameter, culm wall thickness, bending moment, culm length, breaking strength, cellulose, lignin, and culm base weight were closely related to a lodging index. According to path coefficient analysis, most important traits were culm length, stem diameter, thickness of clum wall, and top plant weight.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.3
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• pp.248-252
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• 1999

This study examined the effects of growth retardants and midsummer drainage on lodging-related characters in direct seeding rice culture on flooded paddy surfaces. Treatments included in this study were continuous flooding, two time midsummer drainages (TTD), and inabenfide or trinexapac-ethyl application after TTD. Culm length was reduced most by 11.4cm in trinexapac-ethyl treatment after TTD, followed by 4.1cm in inabenfide treatment after TTD compared to TTD treatment. A significant reduction in culm length occurred at the 3rd internode in inabenfide treatment applied at 40 days before heading (DBH), while trinexapac-ethyl application at 8 DBH reduced the 3rd>2nd>1st internode. The culm diameter of the 4th internode was increased by the application of trinexapac-ethyl following TTD compared to TTD treatment. Thickness of culm wall was significantly increased by trinexapac-ethyl but not by inabenfide applications. Lodging index was the highest in continuous flooding and the lowest in trinexapac-ethyl treatment after TTD. Subsequently, field lodging did not occur in plots treated by trinexapac-ethyl. Rice plants subjected to midsummer drainage or growth retardants showed higher ripened grain ratio and 1000-grain weight, resulting in higher rice yield. These results indicate that trinexapac-ethyl, which can be applied at the relatively later growth stage after proper judgement of lodging occurrence, could be a useful tool for reducing lodging in direct seeding rice culture on flooded paddy fields.

• Proceedings of the Korean Society of Crop Science Conference
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• 2004.04a
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• pp.214-215
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• 2004

• Korean Journal of Weed Science
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• v.14 no.2
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• pp.144-155
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• 1994

Scanning electron micrography and Transmission electron micrography studies were performed on the surfaces of stem(coleoptiles) of rice and barnyardgrass under various cropping patterns at 5 days after seeding or transplanting. Stem surfaces of rice under dry condition possessed rodlet-like epicuticular waxes, trichomes, stomata and cork cell layer in both broadcast and drilled rice while barnyardgrass had only thread-like epicuticular waxes, but trichomes, stomata and cork cell layers were not found. However, rice under water condition has no rodlet-like waxes, stomata and cork cells, and barnyardgrass was similar to that under dry condition. On the other hand, those on stems of 8-day and 25-day transplanted rice were well arranged and developed compared with those of direct seeded rice. Electron micrography showed significant difference in thickness of outer epidermal cell walls of rice and barnyardgrass under dry, water and transplanting condition. Thickness of outer epidermal cell was greater in transplanted rice, dry direct seeded rice, water-direct seeded rice and barnyardgrass in descending order.

• Current Research on Agriculture and Life Sciences
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• v.18
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• pp.33-42
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• 2000

A field case study was performed to investigate the effect of shallow ponding in paddy field on irrigation water requirement of direct seeded rice. In addition, an economic analysis was made to see the effect of no-till direct seeded rice on cost reduction. A field study was performed at a 2.1ha paddy field in Kimjae city, Chonbuk province from 1991 to 1999. Various direct seeding methods such as dryland seeding, wetland seeding, and no-till wetland seeding were introduced. Then, cost reductions due to the direct seeding and no-till were calculated. In addition, to investigate the effect of shallow ponding on irrigation water requirement, field measurements such as irrigation water volume, drainage water volume, rainfall depth, and ponding depth, were made at a 40a plot within the same area in 1988 and 1990. The results of the shallow ponding study showed that the irrigation water depth, rainfall, and the drainage depth were 379mm, 458mm, and 448mm in 1988 growing season, and 274mm, 819mm, and 736mm in 1990, respectively. The shallow ponding irrigation method saved irrigation water by about 20% with higher yield compared with the traditional method. The economic analysis showed that won \640,000 per ha can be saved by direct seeding due to no nursery cost, and \1,220,000 per ha due to no-till and no nursery cost. The yields ranged 540 to 640 kg per 10a during the study period with an average of 590kg per 10a. If these cropping techniques with no-till direct seeding and shallow ponding depth for rice cropping prove to be advantageous with further study, they can be adopted for the most of the paddy fields in Korea.

• Korean Journal of Weed Science
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• v.13 no.1
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• pp.26-35
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• 1993

Differences in weed occurrence was investigated among five types of rice (Oryza sativa L.) cultivation. The five types employed were three transplanting cultivations such as conventional hand transplanting, machine transplanting with 30-day-old seedling, and machine transplanting with 10-day-old seedling and two direct-seedings such as flood direct-seeded rice by pregerminated seed and dry direct-seeded rice by dry seed. Weed specie, occurred varied from 7 to 20, depending on the different cultivation types. Weeds were more diverse in transplanting with l0-day-old seedling than in other transplanting cultivations and in direct-seeding than in transplanting practice. Dominant weed species also varied with cultivation types. In transplanting cultivations Scirpus juncoides Roxb., Echinochloa crus-galli (L.) P. Beauv., and Eleocharis kuroguwai Ohwi were dominant, whereas occurrence of annual weeds such as Cyperus difformis L. and Monochoria vaginalis Presl. aside from the three weed species increased in direct-seeded cultivations.

• Journal of Practical Agriculture & Fisheries Research
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• v.9 no.1
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• pp.91-104
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• 2007

The special project was conducted at the cooperative farm where located at Yakjeon-ri Sukcheon-gun Pyeongannam-do, the Democratic People's Republic of Korea. This farm was firstly introduced a newly developed technology-"Bokto seeding technology" for rice cultivation from the Republic of Korea. Total acreage of rice paddy field cultivated by this technology was 800ha and the average yield was 7.17t/ha with paddy rice which was higher by 109.2% than that of the transplanting method for rice cultivation. In general rice disease was decreased at the Bokto seeded rice plant compared to the transplanted rice plant and root activity was higher in Bokto seeded rice. Optimum seeding amount was determined at rate of 90kg/ha in Pyeongdo 5(early ripening variety) and 110kg/ha at Pyeongdo 11(medium ripening variety) and Pyeongyang 43(late ripening variety), respectively. A recommended sowing time was within late April for late ripening variety like Pyeongyang 43, May 1-5 for medium ripening variety, and May 5-15 for early ripening variety.