• Korean Journal of Food Science and Technology
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• v.17 no.5
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• pp.399-402
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• 1985

Polished rice was stored for 24 weeks at $28^{\c수분함량이 16.0% after infestation with rice weevil (Sitophilus oryzae), inoculation with a storage mold, or both treatment. The moisture contents of stored rice with and without rice weevil were 16.6%-17.3% and 13.70%-14.1% respeotively. Fungal numbers were $4.3{\times}10^{6}$/g to $7.2{\times}10^{6}$/g with insects while no fungal growth occurred without them. There were considerable differences between rice weevil infested- and non-infested rice in rice kernel hardness, 1000 kernel weight, maximum viscosity on amylogram, reducing sugar content, fat acidity, and n-hexanal content in head space gas.

• Journal of Plant Biology
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• v.14 no.3
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• pp.60-65
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• 1971

In order to observe the factors affecting light utilization efficiency in the canopy of a rice crop grown in reclaimed saline areas in Korea, 22 varieties of rice were cultured at the average salt concentration of 6.05mmhos/cm $25^{\circ}C$, (0.39%) in saline soils and non-saline silty loam soils. The inhibition of tillering ability by salt damage at the maximum tillering stage was greater than to growth in height. A significant direct correlation was observed between both ratios and salt concentration with each variety. In the salty areas the length of the flag leaf of the maturing stage showed a positive correlation with the production of rough rice while other living leaf showed a negative correlation. LAI of maturing stage was less in the salty area than in the non-salty area, while the former showed higher ratio in net assimilation and translocation to head with greater RGR before and after the heading stage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.33-36
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• 2005

In order to find out better cultivation practices in mid-mountainous area to produce high quality rice, an experiment involving four transplanting times and four varieties was carried out, during past three years $(2002\~2004)$. There was no significantly different on palatability of rice between transplanting time, but an interaction effect was between transplanting time and variety, The palatability of milled rice of Sangmibyeo, Hwayongbyeo and Junambyeo transplanted at May 10th were higher than Samcheonbyeo. The palatability of milled rice grown by May 20th day's transplanted, Sangmibyeo and Junambyeo were higher than Samcheonbyeo. The palatability of milled rice grown by May 30th day's trans-planted, Sangmibyeo and Hwayongbyeo were higher than Samcheonbyeo and Junambyeo. And the palatability of milled rice grown by June 9th day's transplanted, Sangmibyeo and Samcheonbyeo were higher than Hwayongbyeo and Junambyeo. It can infer that Sangmibyeo is one of the best option over the transplanting times in term of palatability, Amylose content of milled rice was showed without a significant difference between transplanting time, but there was an interaction effect between transplanting time and variety. The amylose content of grown by May 20th day's transplanted, Sangmibyeo and Samcheonbyeo were lower than Junambyeo. The amylose content of milled rice grown by June 9th day's transplanted, Sangmibyeo and Samcheonbyeo were lower than Hwayongbyeo and Junambyeo. And the amylose content of milled rice grown by May 10th day's and May 30th day's transplanted, was showed without a significant difference between variety. The protein content of milled rice grown by later season transplanted was lower than grown by earlier, The head rice yield wasn't different significantly between the treatment of transplanting times and varieties. But the yield of milled rice grown by transplanted at May 20th day was high most in between the treatment of transplanting time. In a conclusion gathering all above the results, 20th May day's transplanting time and Sangmibyeo was one of the best option for producing high quality rice among the treatments in considering with head rice yield, palatability, amylose${\cdot}$protein content and productivity, at Mid-mountainous area.

• Journal of Biosystems Engineering
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• v.31 no.6 s.119
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• pp.482-488
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• 2006

Application of precision farming technology to rice cultivation could be an effective measure for rice quality improvement and environment-friendly agriculture. This study was conducted to develope a variable rate pneumatic granule applicator. Previous study reported that application uniformity of the prototype machine (C.V. = 23.3%) was not satisfactory. To improve the uniformity, increase of blow-head number from 12 to 16 was suggested. Analysis of the pneumatic conveying system showed that increase of number of blow-head was possible. Three-way variance analysis of the modified applicator showed that inserting length should be changed according to granule metering rate. The range of metering rate from 27.3 to 417.9 g/s were divided into 4 levels and 4 sets of inserting lengths were determined to ensure CV values less than 15%. The revised applicator showed satisfactory C.V. values of 9.4 to 14.6% in the metering rate. Granule conveying pattern was observed using a high speed camera and judged as the homogeneous flow pattern.

• Korean Journal of Agricultural Science
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• v.33 no.2
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• pp.159-166
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• 2006

Threshing loss was increased due to dropping of the threshing efficiency when the 4 row head-feed combine harvested 5 row rice to improve harvesting performance of a combine. Reasonable design criteria were examined to determine the ranges of both of feed rate and the length of threshing drum for the 4 row head-feed combine being used as a 5-row combine. Harvesting performance increased as working width or working speed increased, it resulted in 15% increase when the working width increased from 4 row to 5 row. Harvesting operations of the 4 row combine performed normally in the 4 row rice in threshing loss less than 1%, however, threshing loss increased to 2.25% in the 5 row due to poor threshing efficiency. The length of threshing drum was increased from 710 mm to 810 mm as well as the speed of crop feed chain was increased from 0.61 m/s to 0.75 m/s so as to improve the poor threshing efficiency resulted from the enlarged working width from the 4 row to the 5 row, which would decrease threshing loss less than 1%.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.spc
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• pp.31-36
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• 2008

This study was carried out to clarify the effect of silicate application on rice grain quality and storage characteristics in Ilpumbyeo cultivar. In yield and yield components, panicles and spikelet numbers were increased and ripened grain rate was also increased by 2%. Head rice yield was increased by $7.7{\sim}9.5%$ in silicate application. Protein content of milled rice was reduced by $0.2{\sim}0.3%$ and head rice rate was increased by $2.9{\sim}6.7%$ in silicate application due to decrease of chalky and damaged rice rate. In milling characteristics, color separation rate was improved by $4.2{\sim}7.2%$ and colored rice rate was decreased by $5.5{\sim}16.6%$ in silicate application. Acid value of stored brown rice were increased slowly in low temperature and silicate application, but that in room temperature and no silicate application was increased remarkably. The best degree rate of stored brown rice (over than 7.5 of pH) measured by the pH of grain was increased by the silicate application in both low and room temperature. Therefore, it was suggested that the storage characteristics of rice grain was improved by the silicate application.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.62-68
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• 2005

The characters associated with the rice quality and the factors as the proper harvesting time of rice were examined from 2002 to 2004 at Iksan in Honam plaine area. The rice cultivars tested were Samcheonbyeo (Early maturing one). Hwaseongbyeo(Medium maturing one) and Nampyeongbyeo(Mid-late maturing one). The ripened grain rates were high when the harvesting dates after heading were between 50 to 55 days,55 to 60 days, and 60 days for Samcheonbyeo, Hwaseongbyeo and Nampyeongbyeo, respectively. The yield of rice were higher when harvested 45 to 50 days, 50 to 55 days, and 55 to 60 days after heading for Samcheonbyeo, Hwaseongbyeo and Nampyeongbyeo. The highest yields of head rice were obtained when harvested 45 days after heading, 50 days and 55 to 60 days for Samcheonbyeo, Hwaseongbyeo and Nampyeongbyeo. In conclusion, in Honam plain, taking the head rice production, rice quality level, protein content and palatability of rice into account, the best harvest times were found to be 52 days(accumulated temp. : $1,213^{\circ}C$) after heading, 56 days$(1,221^{\circ}C)$, and 60 days $(1,207^{\circ}C)$, for Samcheonbyeo, Hwaseongbyeo and Nampyeongbyeo, respectively.

• The Korean Journal of Food And Nutrition
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• v.13 no.1
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• pp.21-27
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• 2000

In order to investigate the changes of rice qualities during 4 years storage of paddy in warehouse of normal temperature condition. As storage period go by, head ratio was deduced and broken rice was increased according as a change of temperature during the long term storage. A color of rice was became more dark gray than that of entering time as L value was decreased from 64.07 to 61.62 a 4 years late. As a results of studies on the cooking quality of milled rice, water uptake ratio and expanded volume were increased in proporation to storage period, wherease total solids and iodine blue value were decreased. In the characteristic of texture of cooked rice, viscosity/hardness ratio(-H/H) had a decreasing tendency, while adhesiveness and cohesiveness increased with increased storage time. The qualities of cooked milled rice studied were sensory attributies of odor, taste, stickiness and appearance which were evaluvated by multiple comparsion method. The sensory results showed that all of descriptions were deterirated with a increased storage period. The taste and stickiness were changed from good score to bad score a 2 years later.

• Journal of Biosystems Engineering
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• v.43 no.4
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• pp.296-302
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• 2018

Purpose: The aim of this study was to determine appropriate threshing and selection conditions for sorghum harvesting using a rice combine-harvester. Methods: Sorghum harvesting performance was tested using an actual rice combine. Through this test, the grain loss rate and the composition of crops according to the engine and fan speeds of the combine were investigated. Furthermore, the optimal threshing and selection conditions were determined by carrying out a harvest test based on the opening size factor of the concave in a test field. Results: The grain loss rate for the sorghum using a concave ($18{\times}18mm$) of the rice combine was the lowest at 0.1% at a chaffer angle of $40^{\circ}$, engine speed of 2000 rpm, and fan speed of 20 m/s, but the sorting sieve clogged frequently. Furthermore, as the engine speed and fan speed increased, the grain loss rate also increased. The sorghum harvesting test results of the combine according to the concave opening size showed that the grain loss rate was 0.5% at a driving speed of 0.5 m/s, with a concave opening diameter of 13 mm, a chaffer angle of $40^{\circ}$, a concave sieve oscillation frequency of 4.8 Hz, a fan speed of 20 m/s, and an engine speed of 2000 rpm. Conclusions: Findings showed that sorghum could be harvested using a head feeding rice combine.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.122-122
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• 2022

In order to investigate changes in rice yield and quality according to phosphate and potassium fertilization levels when nitrogen fertilizer was applied at 7 kg·10a^-1, a field experiment was conducted at National Institute of Crop Science of Korea in 2021. Three Korean rice varieties were grown in paddy fields, and phosphate and potassium fertilizer were treated at three levels(N-P-K 7-4.5-5.7 kg·10a^-1, 7-3-3 kg·10a^-1, 7-0-0 kg·10a^-1). When phosphate and potassium fertilizers were not treated, the yield of Ilpum and Chilbo was significantly reduced, and there was no significant difference in Hopyung. The head rice ratio was significantly lower in the untreated plot of Hopyung and Chilbo, but there was no significant difference in the Ilpum. Protein content was significantly decreased in the untreated plot of Chilbo, and there was no significant difference in other varieties. As a result of this study, it was confirmed that yield, head rice ratio, and protein content were lowered when phosphate and potassium fertilizers were not treated, and the degree of decrease was different depending on the variety.