• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.4
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• pp.413-416
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• 2008

The cultivation of green manure crop is considered as a good management practice by increasing soil organic matter and fertility levels. This experiment was conducted to improve the soil environment under rice-based cropping system at paddy soil (fine loamy, mixed, nonacid, mesic, family of Aeric Fluventic Haplaquepts) in National Institute of Crop Science (NICS), Korea in 2006 to 2007. The variation of soil temperature in green manure plots was lower than without green manure (control) during spring season (April to May). The temperature variation of no tillage plot (broadcast before rice harvest) was the lowest among treatments. After green manure cropping, the soil bulk density and porosity ratio were improved at the top soil. The production of green manure was the highest athairy vetch and barley mixture plot by partial tillage. However, mixture treatment had no improvement on soil organic matter. After rice cropping with green manure application, soil quality was improved such as soil physical properties except mixture treatment. Therefore, we suggest that soil quality should be improved by green manure cultivation under rice-based cropping system.

• Mycobiology
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• v.35 no.4
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• pp.226-229
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• 2007

To produce fruiting bodies of Oudemansiella mucida, porcelain fungus, on the oak sawdust medium, additives suitable for the mycelial growth and fruiting body formation were screened. In general, the mycelial growth of the three strains of O. mucida used in this study have been good on oak sawdust mixed rice bran of $20{\sim}30%$. The mycelia incubated in potato dextrose broth for 7 days were inoculated on oak sawdust medium supplemented with various ratios of rice bran and incubated for 30 days at $25^{\circ}C$ in the dark condition until the mycelia of O. mucida fully colonized the media from top to bottom. Then, top surface of the media in the bottles were horizontally scratched with a spatula and filled with tap water for 3 hours. To induce the primordial formation of O. mucida, the bottles were transferred to the mushroom cultivating room under 12 hrs of light (350 lux) and dark condition with relative humidity of 95% at $17^{\circ}C$. The primordia of O. mucida were formed on the surface of oak sawdust media after 7 days of incubation. The mature fruiting bodies were observed 5 days after primordial formation. The fruiting bodies O. mucida were formed on oak sawdust medium mixed with 5 to 30% rice bran. However, abundant fruiting-bodies of O. mucida were produced in oak sawdust medium supplemented with 20% rice bran. This is the first report associated with an artificial fruiting body production of O. mucida in Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.1
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• pp.20-25
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• 1999

This experiment was conducted to elucidate the relation-ship between vertical distribution of rice roots and yield traits under field conditions. Eight IRRI's new plant type rices (NPTRs) were tested in a volcanic ash soil paddy field under dense (IO 10 cm) and common (20 20 cm) planting densities. These lines were evaluated to have more spikelet numbers per panicle (SNP), lower filled grain rate (FGR), and lower rough grain weight per hill (RGWH). In dense planting, rough grain weight per stem (RGWS) was increased due to heavier culm and leaf dry weight (CLDW), and both RGWS and CLDW were related with the percentage of root distribution (%RWI) in the 10~30 cm soil layer, while in common planting, RGWS was not closely related with CLDW. SNP was highly related with root dry weight (RDW) in the 0~10cm soil layer. FGR was mainly affected by ROW in the 10~30 cm soil layer under both planting densities. RGWS was positively correlated with top dry weight (TDW) and harvest index (HI), and TDW was positively correlated with RWI under common planting or %RWI under dense planting, and HI was positively correlated with RWI in the 10~30 cm soil layer only under dense planting. RGWS was closely related with root weight index by dry weight (RWI) in the 10~30 cm soil layer and %RWI in the 0~30 cm or 10~30 cm soil layer under dense planting, and with only RWI in the 10~30 cm soil layer under common planting. But RGWH showed the close positive relationship with RDW and RWI in the 10~30 cm soil layer under dense planting, while under common planting, it showed the close positive relationship with RWI and %RWI in the 10~30 cm soil layer or %RWI in the 0~30 cm soil layer. The deeper root system in rice, especially under dense planting, is important for high yield of NPTRs focusing on the increment of top mass production and harvest index.

• Korean Journal of Agricultural Science
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• v.50 no.2
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• pp.231-239
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• 2023

Ammonia (NH₃) emitted from the use of fertilizers during agricultural practice generates particulate matter and odors. The application of carbonized rice husk, an eco-friendly material, is one of the measures used to reduce NH₃. The objective of this study was to evaluate the effect of the application rate and pH of carbonized rice husk on NH₃ emissions and soil quality. An experiment to assess NH₃ emissions was performed in a glasshouse using a static chamber method. The pH of the carbonized rice husk was divided into acidic, neutral, and basic groups, and the carbonized rice husk application rates were 1, 3, and 5% of the soil weight. NH₃ emissions showed a sharp increase within three days after the inorganic fertilizer was applied. Subsequently, NH₃ emissions decreased rapidly after basal fertilization compared to primary and secondary top-dressing. When carbonized rice husks were applied to soil, NH₃ emissions decreased in all treatments, and neutral carbonized rice husk was the most effective in comparison with acidic and basic carbonized rice husk. The application rate of carbonized rice husk and NH₃ emissions showed a negative correlation, and the lowest emissions were found in units with a 5% application rate. Also, there was no statistically significant difference between NH₃ emissions according to the application rate of carbonized rice husk, and when carbonized rice husks were applied at a 5% rate, soil OM increased excessively. Therefore, it is recommended to apply only 1% neutral carbonized rice husk to most effectively reduce NH₃ emissions in the soil.

• Journal of Biosystems Engineering
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• v.37 no.3
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• pp.184-191
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• 2012

Purpose: This study was conducted to investigate the storage and quality characteristics of brown rice under the low temperature warehouse conditions using ambient cold air in the winter. Methods: This new technique maintains rough rice warehouse temperature below $15^{\circ}C$ without cooling operation until the end of May. Four hundred tons of rough rice were stored in the low temperature grain warehouse, and were aerated from the top to the bottom using ambient cold air in February. The quality of rough rice was evaluated from February through October. Results: The results were as followings. Moisture contents of rough rice in the low temperature storage had decreased less than the ordinary temperature storage. Cracked rate of brown rice in the ordinary temperature storage and low temperature storage increased by 4~10.8% and 1.6~7.2%, respectively. The germination rate of rough rice under the ordinary and the low temperature warehouse decreased by 15.0~25.0% and 1.7~8.0%, respectively. The acid value of brown rice under the ordinary and the low temperature warehouse increased by 3.67~6.72 KOH mg/100g and 3.08~4.08 KOH mg/100g, respectively. Conclusions: The result indicates that low temperature storage using ambient winter air showed better maintaining germination of rice, less change of physiological activities and cracked kernel, and better maintaining of rice quality, comparing the ordinary temperature storage.

• Journal of Food Hygiene and Safety
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• v.23 no.3
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• pp.239-247
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• 2008

Objective of this study was to investigate residual the levels of heavy metals in rice grain and soils of "Top-Rice" and common rice cultivation areas from 2005 to 2007. Soil and rice grain samples were taken from 33 "Top-rice" areas and neighboring paddies, and analyzed for the elements using ICP-OES and ICP-TOF-MS after acid digestion. A concentration of arsenic in paddy soil was 1.33 mg/kg which was below 1/5-1/11 fold of the threshold levels(concern: 4 mg/kg, action: 10 mg/kg), and paddy soil was 0.06 mg/kg of Cd(cadmium) being below 1/25-1/67 fold of the limits(concern: 1.5 mg/kg, action: 4 mg/kg). A level of Cu(copper) in paddy soil was 4.57 mg/kg which was below 1/11-1/27 fold of the threshold levels(concern: 50 mg/kg, action: 125 mg/kg), and Pb(lead) concentration in paddy soil was found to be a 4.68 mg/kg. In addition, Hg(mercury) concentration in paddy soil was to be a 0.03 mg/kg, which was below 1/131-1/328 fold of the threshold levels(concern: 4 mg/kg, action: 10 mg/kg). The average concentrations of As, Cd, Cu, Pb and Hg in the polished rice samples were 0.037, 0.043, 0.280, 0.048 and 0.002 mg/kg, respectively. These levels are lower than those of other countries in rice grains. Assuming the rice consumption of 205.7 g/day by total dietary supplements in Korea, the amount of total weekly metal intake of As, Cd, Cu, Pb and Hg by polished rice were estimated to be 0.0892, 1.035, 6.712, 1.161 and 0.054 ${\mu}g/kg$ body weigh/week, respectively. The PTWI(%) of As, Cd, Cu, Pb and Hg were 5.95(inorganic arsenic), 0.26(total arsenic), 14.79, 0.19, 4.65 and 1.07% estimated to be 0.0892, 1.035, 6.712, 1.161 and 0.054 ${\mu}g/kg$ body weigh/week, respectively. In conclusion, it was appeared that the heavy metals contamination in the brown and polished rice should not be worried in Korea.

• Proceedings of the Korean Society of Crop Science Conference
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• 2001.05a
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• pp.128-129
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• 2001

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.805-809
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• 2008

Measurement of leaf area index (LAI) is useful for understanding rice growth, water use, and canopy light interception. The top nitrogen content(TNC) per unit area is an important quantitative index of the condition of nitrogen nutrition in rice production. The rapid and simple method of estimation of TNC, with the use of the existing nondestructive analyzing instruments chlorophyll meter SPAD-502 and plant canopy analyzer (PCA) LAI-2000, was scrutinized. Destructive measurement is time consuming and labor intensive. Our objective was to evaluate sampling procedures using the Li-Cor LI-1800, LAI 2000 plant canopy analyzer (PCA) for nondestructive estimation of rice LAI, and SPAD-502 on the Northern Plains of Cheongju. The LAI estimated by PCA tended to underestimate the LAI determined by actual measurement by about 20%. The estimation of LAI by PCA was judged to have a sufficient accuracy as a practical technique. A high positive correlation was obtained between the values of the SPAD reading and LAI. NDVI and LAI also showed a very high correlation. The values of the SPAD reading and LAI, and NDVI gave a high positive correlation. These results indicated that the method described in this study was effective as a simple and rapid method for the estimation of rice growth.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.5
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• pp.335-338
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• 2000

The technology of direct-seeding in rice cultivation is an innovation mainly induced by factors in market economy and is rapidly diffused among individual farmhouses. Because the effect of technology can be affected by many factors under various farming circumstances, the impact and stability of the direct-seeding technology compared with transplanting was analyzed under various topographical regions. Yield in direct-seeding was higher in plains, although the farm size producing higher yield was quite different depending on the topographical regions. In the direct-seeding cultivation of rice, man-labor hours was reduced by about 38 percent and the reduction rate showed little difference among topographical regions. Fertilizer was used about 11 percent more but the increase rate varied from 3 to 17 percent depending on regions with higher rates in plains. Application of agricultural chemicals was also increased about 9 percent in direct-seeding, but the increase rate was as high as 12 percent in suburbs. More fertilizer and agricultural chemicals were used in direct-seeding cultivation by farmhouses implementing both direct-seeding and transplanting than by those implementing direct-seeding only. Use of more fertilizers and agricultural chemicals in direct-seeding in all regions may indicate its technical instability. Major problems causing the technical instability of direct-seeding cultivation should be solved by comprehensive research considering various farming circumstances such as topographical features rather than just a top-down style research and extension.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.226-226
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• 2017

This study was to evaluate methods to high quality food ramie rice cake, thereby increasing farm income. This study investigated the effects of different covering material on stable winter survival management with edible leaf in Ramie(Boehmeria nivea L.). The method of winter survival with covering material were conducted under three condition compose to Non covering, Rice straw cutting covered with 500kg.10a-1, Rice husks covered with 1,000kg.10a-1(covered 4~5 cm thickness in the soil surface). Method of application were standard application(N-P-K-Compost applied at 27-9-27-600kg.10a-1. Compost and fused phosphate applied at 100% of basal fertilizer in March 25. 20% of top dressing were four times application in March 25 - October 5. Planting year were March 15, 2011. Plants were spaced 60 cm apart in rows 25 cm apart with open cultivation. According to non covering < Rice husks covered with 1,000kg.10a-1 < Rice straw cutting covered with 500kg.10a-1 cultivation this order, aerial part as a result were plenty amount of growth. Sprout time and winter survival rates was uncovering control plot compared to 2 - 5 days quickly, 45-57% highly by rice husks and rice straw covering. Green leaf yields is untreated control plot (12,44 kg.10a-1) compared to rice husks covering 7% higher, and rice straw covering increased to 18% of the most.