• Journal of Biosystems Engineering
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• v.27 no.1
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• pp.25-32
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• 2002

This study was conducted to develop a dry paddy seeder of strip tillage. The prototype is 8 rows drill seeder, which is composed of a strip tillage, sowing and fertilizing device, and pressing wheels to do the strip tillage, sowing, fertilizing, and draining ditch, simultaneously. The performances of prototype was evaluated through the investigation of fuel consumption, tillage torque, ratio of soil breaking, and economical efficiency and the results were compared with these of a dry paddy seeder that needs whole tillage. According to the USDA textural classification, the experiment field was composed of sandy loam which consisted of 56.8 of sand, 30.2 of silt and 13.0 % of clay, respectively. Its hardness ranged from 952 to 1,673 kPa depending on the soil depth, and its soil moisture content was 24.9%(d. b.) Fuel consumption of the prototype was 5,015g/hr at 2,000 rpm of engine, which was consequently 64% smaller than that of the conventional dry paddy seeder. For the tillage torque, it ranged from 132 to 206N$.$m depending on the tillage pitch, which was 10∼30% smaller than that of the conventional dry paddy seeder. The ratio of soil braking of the prototype was 87∼98%, whereas that of the conventional dry paddy seeder was 80∼97%. The working performance of the prototype was surveyed to be 3.8hours/ha, which was about 5 times higher than that of the conventional dry paddy seeder. The cost reduction of 26.3% was obtained by using the prototype.

• Journal of Environmental Science International
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• v.19 no.8
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• pp.1025-1034
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• 2010

This study was to analyze changes of landuse and environmental value of cultivate land for eight years from 1999 to 2007 year in greenbelt area, Seoul. Greenbelt area decreased from $166.82\;km^2$ in 1999 to $156.50\;km^2$ in 2007 according to removal policy. Regarding landuse status in 2007, forest field area accounted for 64.16 %, dry paddy area 4.10 %, facilitated farming area 3.82 %, rice paddy area 2.95 % out of total greenbelt area. Cultivate land occupied wide spaces with dry paddy area, facilitated farming area, tree nursery in Seocho-gu, Gangnam-gu and Gangdong-gu. Changes of landuse were serious in Seocho-gu. The trend of changes of landuse for eight years is that rice paddy area was changed dry paddy area by laying the ground and dry paddy area was changed facilitated farming area for intensive agriculture. Rice paddy area could change without permission by laying the ground in below 50 cm height and it was changed to green houses due to increase in profit and modern policy of agriculture. It is nessary to monitor landuse regularly, improve regulation for change of landuse, compensate a property loss for maintaining environmental value in greenbelt area.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.690-696
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• 1995

Properties of dry milled rice flours made of paddy with different moisture content (12.6, 18.4 and 24.4%) were compared with those of wet milled rice flour. Among dry milled rice flour, the higher moisture content of paddy the finer particle size and the more distinct shape of starch were observed. As the moisture content of paddy increased, L (lightness) value and water absorption index of rice flour were increased, while setback in amylogram and water soluble index were decreased. Lower gel consistency and gel strength were found in dry milled rice flours than in wet milled rice flour, while no significant difference was found among dry milled rice flours. Enthalpy for melting crystalline of retrograded gels was higher in dry milled rice flours made of paddy with 24.4% moisture content than in other dry milled rice flours. Wet milled rice flour had lower retrogradation enthalphy than dry milled rice flours.

• Asian Journal of Atmospheric Environment
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• v.11 no.3
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• pp.202-216
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• 2017

Nitrogen (N) is an essential macronutrient. Thus, evaluating its flows and stocks in rice paddy ecosystems provides important insights into the sustainability and environmental loads of rice production. Among the N sources of paddy fields, atmospheric deposition and irrigation inputs remain poorly understood. In particular, insufficient information is available for atmosphere-rice paddy exchange of gaseous and particulate reactive N (Nr, all N species other than molecular N) which represents the net input or output through dry deposition and emission. In this study, we assessed the N inputs via atmospheric deposition and irrigation to a Japanese rice paddy area by weekly monitoring for 2 years with special emphasis on gas and particle exchange. The rice paddy during the cropping season acted as a net emitter of ammonia ($NH_3$) to the atmosphere regardless of the N fertilizer applications, which reduced the effects of dry deposition to the N input. Dry N deposition was quantitatively similar to wet N deposition, when subtracting the rice paddy $NH_3$ emissions from N exchange. The annual N inputs to the rice paddy were 3.2 to $3.6\;kg\;N\;ha^{-1}\;yr^{-1}$ for exchange, 8.1 to $9.8\;kg\;N\;ha^{-1}\;yr^{-1}$ for wet deposition, and 11.1 to $14.5\;kg\;N\;ha^{-1}\;yr^{-1}$ for irrigation. The total N input, 22.8 to $27.5\;kg\;N\;ha^{-1}\;yr^{-1}$, corresponded to 38% to 55% of the N fertilizer application rate and 53% to 67% of the brown rice N uptake. Monitoring of atmospheric deposition and irrigation as N sources for rice paddies will therefore be necessary for adequate N management.

• 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.

• 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).

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.6
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• pp.662-668
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• 2016

No-tillage dry-seeding of rice can offer potential benefits by reducing time and labor cost compared with conventional tillage practices. This study was conducted to investigate the effects of no-tillage dry-seeding on rice growth and soil hardness in comparison with other rice cultivation methods, machine transplanting and wet-hill-seeding on puddled paddy. The seedling stand fell within optimum range for both no-till dry-seeding and wet-hill-seeding on puddled paddy. Plant height, number of tillers and SPAD values in no-tillage dry-seeding cultivation were higher than those observed in other methods. There were no significant differences in grain yield of rice among three cultivation methods. The quality characteristics of milled rice grown in no-tillage dry-seeding were similar to those grown in other cultivation methods. Soil hardness in top 10 cm depth was significantly higher in no-tillage dry-seeding than other cultivation methods, while soil hardness below 10 cm depth was highest in machine transplanting cultivation. Results indicate that no-tillage dry-seeding practice is comparable to conventional tillage system in terms of seedling establishment, growth, yield and grain quality.

• 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.

• 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

• 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.