• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.spc
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• pp.47-52
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• 2008

This study was carried out to improve the rice grain quality of Ilpum cultivar, especially to reduce the chalky rice rate by controlling top dressing of nitrogen application ratio at the tillering and panicle initiation stage. In the rice plant growth, the number of tiller and leaf area index of maximum tillering stage were influenced by basal dressing and top dressing at tillering stage; however those of heading stage were mainly influenced by top dressing at panicle initiation stage. In yield and yield components, they were influence by the top dressing at panicle initiation stage and the rice yield was increased by percentage of the top dressing. The protein content of rice grain was increased as the rate of top dressing at panicle initiation stage was increased. The rate of chalky and damaged rice was remarkably increased as the top dressing ratio was increased, resulting in reducing the rate of head rice rate. As the results, the characteristics of milling and rice quality was improved when the amount of top dress was reduced as 50% at the panicle initiation stage, and the yield of head rice also increased.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.4
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• pp.323-327
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• 2002

Plant growth and the two components of respiration, growth and maintenance, were compared between low and high nitrogen applications in hydroponic culture on a high-yielding rice cultivar 'Takanari' (Oryza sativa L.). Grain yield decreased by high nitrogen application, and thus this cultivar has low adaptability to nitrogen. Growth efficiency (GE) and net assimilation rate (NAR) were lower in the high-nitrogen plot. The maintenance coefficient (m) and growth coefficient (g) of dark respiration were 0.0111 $d^{-1}$ and 0.196 in the low-nitrogen plot and 0.0166 $d^{-1}$ and 0.237 in the high-nitrogen plot, respectively. Thus, high nitrogen application increased both g and m. Calculated $R_m$ (maintenance respiration rate) was 70 and 90% of total respiration rate at heading, respectively. The significance of nitrogen adaptability and g was discussed.

• Magazine of the Korean Society of Agricultural Engineers
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• v.37 no.5
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• pp.53-61
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• 1995

Analyses of subsurface drainage effects of farmland with respect to pipe and envelop material are made by the laboratory experiments using soil box to give basic information for the subsurface drainage system planning and design. Three different diameter PVC perforated pipes and a mesh pipe are used with envelop materials such as sand, rice bran, and crushed stone. Steady state subsurface drainage flow rate increased as envelop material changed from sand to rice bran and crushed stone. This indicates that as the hydraulic conductivity of the envelop material increases, the drainage flow rate increases. On the other hand, for a given envelop material, the mesh pipe which has the largest openning area shows the largest flow rate while small diameter PVC pipes show small flow rates. This tells that as the openning area and pipe diameter increase, the flow rate increases, too. Therefore, selection of pipe and envelop material should be made in accordance with the design drainage flow rate. Unsteady state subsurface drainage flow rate with respect to time differs for different envelop material. In case the sand was used as an envelop material, the small diameter PVC pipes show larger flow rates than the large diameter PVC pipe and mesh pipe. When the rice bran was used, the mesh pipe shows the largest flow rate, while small diameter pipes show smaller flow rates. In case the crushed stone was used as an envelop material, the large diameter PVC pipe and mesh pipe show larger flow rates, while small diameter pipes show a little bit smaller flow rates. However, the variation of flow rates among different pipes is the smallest when the crushed stone is used. The flow rate curve with respect to the pipe changes little for the crushed stone envelop which has a large hydraulic conductivity, while that changes much for the sand and rice bran envelops. However, it is difficult to draw a consistent relationship between the drainage flow rate and pipe for all the envelop materials. Since the subsurface drainage experiments are made only under the restricted laboratory condition in this study, further study including field experiment is required.

• Korean Journal of Food Science and Technology
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• v.18 no.2
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• pp.110-113
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• 1986

Effect of defatting on the hydration rate of Akibare (Japonica) and Milyang 30 (J/lndica) rice was investigated. Relative crystallinity of rice starch and width of the rice grain were decreased by defatting, which was more pronounced for Milyang 30. The moisture gain at $10^{\circ}{\sim}40^{\circ}C$ for 80 min and the hydration rate of the defatted Milyang 30 rice were lower and higher than those of the defatted Akibare rice, respectively. The activation energy for hydration of rice was not affected by defatting.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.1
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• pp.99-108
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• 2012

Soil erosion and sediment from agricultural farmland has caused various negative impacts on environment in recent years. The effect of rice straw mat on soil erosion has been investigated by many researchers these days. In this study, the SWAT model was applied to Hongcheon watershed to evaluate SWAT flow and sediment, and the effect of rice straw mat on sediment yield at watershed outlet was evaluated. The Nash-Sutcliffe model efficiency (NSE) and coefficient of determination ($R^2$) values for flow simulation (calibration period) were 0.66 and 0.67, and the NSE values for sediment was 0.90. The calibrated parameters were used to analyze the reduction of sediment yield in the farmland with rice straw mat. Average daily sediment yield without rice straw mat was 49.8 ton/day and sediment yield with rice straw mat was 25.5 ton/day, and the reduction rate was 38.7 %. Also, average daily sediment yield with/without rice straw mat were 97.5 ton/day and 190.7 ton/day during the rainy season (Jun. 2008 - Aug. 2009), with the reduction rate 46.3 %.

• Asian-Australasian Journal of Animal Sciences
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• v.1 no.1
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• pp.21-25
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• 1988

The rumen degradability of rice straw (untreated, urea-sprayed, urea-treated), grasses (Panicum maximum, Pennisetum clandestinum) and rice bran was compared. The mean in vivo organic matter digestibility of the untreated (US), urea-supplemented (SS) and urea-ammonia treated (TS) rice straw were 50.9, 53.9 and 57.4%, respectively. Rice bran contained extremely high levels of acid-insoluble ash (25.2% DM), and its OMD was 36.1%. Grasses had OMD values around 66%. Degradability measurements were performed with buffaloes using the nylon bag technique. The organic matter (OM) disappearance data were fitted to an model which was used to describe degradation pattern. The mean potentially degradable fraction for US, SS and TS was 61.5, 61.9 and 69.4%, respectively. Urea-ammonia treatment increased both the amount of OM degraded and the rate at which it was degraded in the rumen. Both grasses had similar values for degradable fraction (around 65%) and for rate constant for degradation (0.04). Rice bran contained high proportions of readily soluble material (23.9%), but the degradable OM fraction was only 13.2%. The low quality of rice bran is attributed to the contamination of rice hulls during processing.

• Korean Journal of Plant Resources
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• v.11 no.1
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• pp.93-100
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• 1998

This study was to investigate the dry weight, the amount of Na+ and K+ water potential and leaf photosynthesis rate in plants for determining the salt tolerance mechanism in rice cultivars on soil and solution culture with NaCl. The results obtained in this study are summarized as follows ; In general, rice cultivars, cv. Tetep and Jinbu, having high salt tolerance in ID(identified on dry matter production level) showed the higher salt tolerance in RGR (relative growth rate), compared with rice cultivars(cv. Nonglim 41ho, Dunraebyeo and Sobackbyeo) having low salt tolerance. The contents of Na in rice differed depending on culivars and plant parts. Tetep contained 2.9times higher amounts of Na+ than leaf blade and root part. High salt tolerance cultivar Obongbyeo showed a larger decrease in osmotic potential than low salt tolerance cultivar Dunraebyeo suggesting that osmotic adjustment was developed under salt stress conditions in a salt tolerant cultivar . In order to know the IY(identified on grain yeild level using rice cultivars having different salt tolerance the capacity of photosyntheiss was investigated. The capapcity of photosynthesis in cv. Tetep and Obongbyeo having high salt tolerance was much higher that in cv.Dunraebyeo and Nonglim 41 having low salt tolerance.

• The Korean Journal of Food And Nutrition
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• v.34 no.1
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• pp.1-14
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• 2021

This study evaluated the antioxidant activity and quality characteristics of rice cookie with added butterbur powder in a ratio of 0, 5, 10, 15, and 20% to confirm the possibility of butterbur as a functional food. The moisture content, spread factor, leavening rate, and hardness of rice cookies increased with an increase in the amount of butterbur powder; whereas a decrease in the pH and baking loss rate was observed. The L and b values decreased as the amount of butterbur powder increased, but the value was the lowest when 5% of butterbur powder was added. The sensory liking score showed the highest preference for 10% butterbur powder regarding appearance, flavor, taste, texture, and overall preference. In the principal component analysis (PCA), the addition of 10% butterbur powder positively affected the measure of food acceptance in terms of organoleptic properties of butterbur. Besides, as the amount of added butterbur powder increased, the antioxidant activity of rice cookies increased. Based on these results, it appears that the addition of butterbur powder to rice cookies in a 10% ratio can produce rice cookies with excellent antioxidant activity, overall quality, and high preference.

• The Korean Journal of Food And Nutrition
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• v.25 no.4
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• pp.850-854
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• 2012

This study is carried out in order to develop food materials for the promotion of rice consumption. In this study, we researched the physicochemical properties of extruded rice flour (ER) and gelatinization popped rice flour (GPR) by the extrusion process and by the popped method with milled rice and brown rice. The extrusion process used a couple of screw extruders. The extrusion parameter was kept constant at a feed moisture content of 25%, barrel temperature of $120^{\circ}C$ and screw speed of 400 rpm. GPR was prepared by batch popping machine after gelatinization of rice. In order to evaluate the physicochemical properties of ER and GPR, as well as the gelatinization rate, water soluble index (WSI), water adsorption index (WAI), DPPH radical scavenging activity and total dietary fiber content, the color value was carried out. The gelatinization rate was similar to 71.1~73.8%. Further, the results of WSI and WAI were increased at ER and GPR compared to the raw materials; ER was also higher than GPR. DPPH radical scavenging activity and total dietary fiber content showed a tendency to reduce after extrution and popping. As a result of the color value, the L value of ER decreased more than the raw materials, whereas GPR increased at a and b values.

• The Korean Journal of Food And Nutrition
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• v.30 no.6
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• pp.1252-1259
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• 2017

The objective of this study was to examine the effects of rice (R) and brown rice (BR) flour on the quality characteristics of morning bread. The quality characteristics of morning bread were determined by measuring the pH of the dough, dough raising power, moisture content, baking loss rate, specific volume, height, color value, texture analysis and sensory evaluations. The pH of the bread dough was highest on R1:BR2 and R0:BR3. The dough raising power and moisture content steadily and significantly decreased as the amount of added brown rice flour increased. The baking loss rate was highest on R3:BR0. The specific volume and height of morning bread were highest on R3:BR0 and R2:BR1. In color value, the L value decreased significantly as the amount of added brown rice flour increased, while a value and b value increased. The hardness, gumminess and chewiness of morning bread increased with an increase in brown rice flour. In consumer acceptability, R3:BR0, R2:BR1 and R1:BR2 showed the highest scores in all parameters. Characteristic intensity rating of roasted taste was lowest on R3:BR0. These results indicate that R2:BR1 showed similar quality characteristics as compared to morning bread without brown rice flour, with the optimal results appreciated with a 2:1 ratio of rice flour to brown rice flour.