• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.2
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• pp.88-92
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• 2000

Excessive soil water in paddy field induces growth losses during the vegetative stages of soybean plants. Our objectives were to know growth responses of soybean as affected by the level of ridge heights. A field experiment was conducted at the Research Farm of Korea University near Seoul in 1996. Ten cultivars of soybean (Glycine max (L.) Merrill) were planted at the ridge heights of 10, 30, and 50cm in paddy soil on 27 June. Total dry matter accumulation at the 10cm ridge height was severely decreased until the growth stage of R5 as compared to the ridge heights of 30 and 50cm, and this decrement was mainly due to both reduced leaf and stem dry weights. However, seed dry weight was not significantly decreased at the lower ridge height with the increment of harvest index. Cultivar differences were found on seed dry weight, crop growth rate from R1 to R5, and leaf/stem ratio of R5. From the above results, soybean growth responses to excessive soil water in paddy field were different between seed filling stage and late vegetative to early reproductive growth stages.

• Magazine of the Korean Society of Agricultural Engineers
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• v.39 no.4
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• pp.64-74
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• 1997

The purpose of this study is to analyze hydraulic characteristics of surface irrigation in a paddy field of direct seeding culture. Field experiment was performed in the paddy field of ridge direct dry seeding. Simulation by a numerical model was also accomplished with the data obtained from the field experiment. The model was developed by one dimensional zero-inertia equation and finite difference method. From the result of the field observation, the furrows of the experimental field were found to have various geometric characteristics. Advance distance and time were measured both in the field and by the model simulation for various furrow lengths and irrigation discharges. Roughness coefficients of each furrow were also estimated by the model.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.3
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• pp.237-246
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• 2010

This study was conducted to evaluate growth characteristics and yield of silage corn hybrids by different planting dates at paddy and upland field. Days to silking by different planting dates at paddy field were 81 days at planting on April 22, 70 days on May 20 and 62 days on June 10, respectively, and they were getting shorter as planting date delayed. There was no significant difference in days to silking between paddy and upland field. Plant height in paddy field was no significant difference between at planting on April 22 and on May 20, and it was shortened sharply at planting on June 10. There was no significant difference in plant height between paddy and upland field. There was no significant difference in lodging by different planting dates in paddy field. There was significant difference in lodging between paddy and upland field (P<0.05). There was no significant difference in stay-green by different planting dates in paddy field, and no significant difference between paddy and upland field. Ear ratios to total dry matter in paddy field were 43% at planting on April 22, 41% on May 20 and 28% on June 10, respectively, and it was lower as planting date delayed. There was no significant difference in ear ratios to total dry matter between paddy and upland field. Fresh yields in paddy field were lower with 14% at planting on May 20 and 32% on June 10 compared to on April 22 as planting date delayed. There was no significant difference in fresh yield between paddy and upland field. Dry matter yields in paddy field were higher with 9% at planting on May 20 and lower with 24% on June 10 compared to at planting on April 22 as planting date delayed. Dry matter yield in paddy field was lower with 9% compared to 1,931 kg/10a at planting on April 22. TDN (Total digestible nutrients) yields in paddy field were higher with 5% at planting on May 20 and lower with 28% on June 10 compared to at planting on April 22 as planting date delayed. TDN yield in paddy field was lower with 11% compared to 1,340kg/10a at planting on April 22.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.5
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• pp.558-562
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• 1996

The growth and yield of Job's tears (Coix lacryma-jobi L.) under the flooded paddy and upland (dry paddy) field conditions were compared at three sowing dates and two planting densities. Job's tears grown under flooded paddy field was much shorter in plant height, but greater in number of tillers than those grown under upland. Photosynthesis rate of Job's tears grown under flooded paddy field was higher and the weight of dry roots heavier but the damages of pest and leaf blight disease smaller than those grown under upland. For the above mentioned reasons, the grain yield of Job's tears grown under flooded paddy field was higher by up to 85% than that grown under upland. There was no significant difference in grain yield between the planting densities. The earlier sowing brought about the less grain yield in upland field condition, while sowing plot on the 15th of May showed the highest grain yield in the flooded paddy field condition.

• Korean Journal of Weed Science
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• v.15 no.4
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• pp.305-312
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• 1995

Weed communities in the dry-direct seeded rice(Oryza sativa L.), soybean(Glycine max(L.) Merr.), and dry-direct seeded rice-soybean rotation system from the transplanted rice field were investigated in order to identify a change in weed species by paddy-upland rotation. Echinochloa species was the most dominant species in the dry-direct seeded rice and their great increase was observed in the continued practices of dry-direct seeded rice. Echinochloa spp., Chenopodium ficifolium, and Digitaria spp. were identified as the major weeds in soybean cultivation in paddy field. Practice of soybean rotation in the dry-seeded rice reduced weed occurrence, particularly at the soybean after 2-yr continued dry-direct seeded rice and at dry-direct seeded rice culture after 2-yr continued dry-direct seeded rice and at dry-direct seeded rice culture after 2-yr soybean compared to the continued cultures of rice or soybean. In addition, cultivation of dry-direct seeded rice or soybean culture in the paddy rice field seemed to be helpful for suppression of perennial weeds(Eleocharis kuroguwai, Cyperus serotinus, Scirpus juncoides) and aquatic weeds(Monochoria vaginalis, Sagittaria spp. Potamogeton distinctus).

• Proceedings of the Korean Society of Crop Science Conference
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• 1990.05a
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• pp.32-33
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• 1990

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.3
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• pp.141-147
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• 2019

The purpose of this study was to determine the effect of waterlogging duration on the growth characteristics and productivity of forage corn at different growth stages under paddy field conditions. Treatments consisted of waterlogging at two growth stages (V7 or V14) for four waterlogging durations (no waterlogging, 48 hours, 72 hours, and 96 hours, respectively). The V14 growth stage was more vulnerable to waterlogging than the V7 stage. Among the waterlogging durations, the lodging score increased at 48 hours. The stem height of forage corn decreased with the increase in waterlogging duration at the different growth stages (V7 and V14). Increase in waterlogging duration reduced the stem dry matter yield, ear dry matter yield, and total dry matter yield at both growing stages (V7 and V14). The waterlogging treatments at the V14 stage affected ear dry matter yield more than those at the V7 growing stage. Thus, the management of forage corn under paddy field conditions must be strengthened during early (V7) and grain fill stages (V14). When waterlogging occurs, surface and subsurface drainage should be implemented within 48 hours to control (no waterlogging) the groundwater level and, thus, minimize economic losses due to forage corn damage.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.2
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• pp.119-126
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• 2011

This experiment was carried out to know adaptability and forage production and quality of sorghum, sorghum ${\times}$ sudangrass and sudangrass hybrids depend on drained condition at paddy field from 2007 to 2008 at Chungnam province. Growth, forage production and quality of sorghum, sorghum ${\times}$ sudangrass and sudangrass hybrids showed more well drained condition than poorly drained condition at paddy field. Among growth characteristics, 'SS405' hybrids were somewhat strong for waterlogging, then and good at stem diameter, disease resistance. The dry yield of 'SS405' hybrid at poorly drained paddy field was the highest as 12,938 kg per ha. Fresh yield of poorly drained paddy field was 52.7% compared to that of well drained paddy field. The dry matter yield of poorly drained paddy field was the lower as 66.4% than that of well drained condition. ADF (acid detergent fiber), NDF (neutral detergent fiber), CP (crude protein) and IVDMD (in vitro dry matter digestibility) in poorly drained paddy field were 90.3%, 100.6%, 85.7% and 89.6% level compared to well drained paddy field.

• Korean Journal of Weed Science
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• v.13 no.2
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• pp.159-163
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• 1993

This research was conducted at the Crop Experiment Station to determine the changes of weed flora under direct seeded rice cultivation in dry paddy field from 1989 to 1992 and to establish an effective weed control strategy in direct seeded rice cultivation. With the continuous rice growing under direct seeded rice cultivation in dry paddy field, there were more occurrence in grasses and annual weeds while broadleaf and perennial weeds were diminished. The predominant weeds were aquatic weeds such as Eleocharis kuroguwai, Echinochloa crusgalli, and Monochoria vaginalis in machine transplanted rice paddy field while there were predominant of semi aquatic weed species such as E. crusgalli, Digitaria sanguinalis, Bidens tripartita, Aeschynomene indica, and Arthraxon hispidus in continuous direct seeded rice cultivation in dry paddy condition. Based on the vegetative analysis of weeds in terms of simpson index and community dominance, there was more distribution of weed species in direct seeded rice cultivation on dry paddy condition while only distributed with 1-2 weed species in machine transplanted rice paddy field. In similarity coefficient, there was a gradual increase up to 67% of weeds with the continuous direct seeded rice cultivation in dry paddy condition for 4 years starting from 41% of similarity coefficient.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.3
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• pp.169-175
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• 2022

This study aimed to examine the changes in dry matter yield and growth characteristics of alfalfa (Medicago sativa L.) in response to variations in sowing dates during the autumn season of 2021-22 in a dry paddy field of Chilbo-myeon, Jeongeup-si, Jeollabuk-do. Treatments comprised four sowing dates at 10-day intervals, i.e., October 8, October 18, October 28, and November 8, 2021. The winter survival rate of alfalfa showed a significant difference between different treatments but was at a satisfactory level for all (p<0.05). The winter survival rate for the fourth sowing date, a month later than the first sowing date, was approximately 11.7% lower than that for the first sowing date. The plant height ranged between 82.3-93.1 cm and 60.5-63.7 cm at the first and second harvest, respectively, smaller at the second harvest than at the first harvest. The total dry matter yield of alfalfa was the highest at 13,316 kg/ha for the first sowing date, and the later the sowing date, the lower the dry matter yield. The protein content of alfalfa ranged between 13.6-17.3% in the first harvest, lower than the standard alfalfa protein content of 20% or more. In relative feed value, the first sowing (Oct. 8) was the most significantly higher in the first harvest (p<0.05). These results suggest that the early and mid-October sowing dates are optimum for sowing alfalfa during autumn and result in improved plant growth, dry matter yield, protein content, and winter survival compared to those at later sowing dates. Therefore, dry paddy fields can be safely employed for alfalfa cultivation with sowing dates in early and mid-October during autumn.