• Korean Journal of Agricultural Science
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• v.43 no.3
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• pp.330-339
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• 2016

The effect of transplanting and harvest timing was evaluated for the production of high quality pigmented rice in the Yeongnam plain area. Rice was transplanted on June $2^{nd}$ and $14^{th}$ and harvested between 35 - 55 days after panicle heading at 5 - day intervals. Three black- and 3 red-pigmented rice cultivars (such as early cultivar : Josengheugchal, Jeogjinju; medium cultivar : Heugseol, Hongjinju; and mid-late cultivar : Sintoheugmi, Geongganghongmi) were studied. Yield components like spikelet number, ripened grain ratio, and 1,000 - grain weight of the black- and red-pigmented rice cultivars were similar for both the June 2 and June 14 transplantings but panicle number per $m^2$ was higher for the June 14 transplanting than for June 2. This contributed to a higher brown rice yield for the June 14 transplanting, by 6 - 19% for black-pigmented rice, and by 10 - 21% for red-pigmented rice than the yield for the June 2 transplanting. Total anthocyanin and polyphenol productions of the pigmented rice were also higher in the June 14 transplanting than that in the June 2 transplanting due to high brown rice yield. Based on the combined pigmented brown rice yield, we concluded that the optimal harvest timing would be 40 - 45 days after panicle heading (DAH) for the black-pigmented rice and 45 - 50 DAH for the red-pigmented rice. This study suggests that optimum transplanting and harvest timings play an important role for production of high quality pigmented rice in the Yeongnam plain area.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.264-273
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• 2020

'Ilpum', a Korean short-grain mid-late maturing rice cultivar, was developed in 1990, more than 30 years ago. Despite its age, it has been the most widely grown cultivar in the Gyeongbuk province of South Korea for more than 25 years, making it the most important rice cultivar for the people of the Gyeongbuk province. The aim of this study was to analyze the relationship between the rice yield of "Ilpum', the main rice cultivar in the Gyeongbuk province, and climate elements in the Daegu (southern plain area) and the Andong (inland mountainous area) regions in Gyeongbuk, South Korea. The rice yield over the past five years increased by about 13% and 24%, compared to that produced in the late 1990s in Daegu and the early 2000s in the Andong region, respectively. The number of panicles per hill and the grain ripening rate significantly affected rice yield in the 'Ilpum' cultivars in the Daegu region. The faster heading was a factor in the increase in 'Ilpum' rice yield in the Andong region. The air temperature has been rising and sunshine duration has been increasing from the late 1990s to present in both regions. Rice yield was evaluated to understand the effect of climate factors. The rice yields increased owing to the long sunshine duration during the grain-filling stage in both regions. In Andong, increasing the maximum temperature during the vegetative stage increased rice yield. Rising air temperature during the reproductive stage also increased rice yield. In particular, long sunshine hours throughout the whole rice growing period increased the rice yield of this cultivar in the Andong region.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.4
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• pp.238-246
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• 2005

Rice yield and protein content have been shown to be highly variable across paddy fields. In order to characterize this spatial variability of rice within a field, two-year experiments were conducted in 2002 and 2003 in a large-scale rice field of $6,600m^2$ In year 2004, an experiment was conducted to know if variable rate treatment (VRT) of N fertilizer, that was prescribed for site-specific management at panicle initiation stage, could reduce spatial variation in yield and protein content of rice while increasing yield compared to conventional uniform N topdressing (UN, 33kg N/ha at PIS) method. VRT nitrogen prescription for each grid was calculated based on the nitrogen (N) uptake (from panicle initiation to harvest) required for target rice protein content of $6.8\%$, natural soil N supply, and recovery of top-dressed N fertilizer. The required N uptake for target rice protein content was calculated from the equations to predict rice yield and protein content from plant growth parameters at panicle initiation stage (PIS) and N uptake from PIS to harvest. This model· equations were developed from the data obtained from the previous two-year experiments. The plant growth parameters for the calculation of the required N were predicted non-destructively by canopy reflectance measurement. Soil N supply for each grid was obtained from the experiment of year 2003, and N recovery was assumed to be $60\%$ according to the previous reports. The prescribed VRT N ranged from 0 to 110kg N/ha with an average of 57kg/ha that was higher than 33 kg/ha of UN. The results showed that VRT application successfully worked not only to reduce spatial variability of rice yield and protein content but also to increase rough rice yield by 960kg/ha. The coefficient of variation (CV) for rice yield and protein content was reduced significantly to $8.1\%$ and $7.1\%$ in VRT from $14.6\%$ and $13.0\%$ in UN, respectively. And also the average protein content of milled rice in VRT showed very similar value of target protein content of $6.8\%$. In conclusion the procedure used in this paper was believed to be reliable and promising method for reducing within-field spatial variability of rice yield and protein content. However, inexpensive, reliable, and fast estimation methods of natural N supply and plant growth and nutrition status should be prepared before this method could be practically used for site-specific crop management in large-scale rice field.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.1
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• pp.78-83
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• 2013

The excessive and indiscriminate use of chemical fertilizers in the past has brought serious soil and other environmental problems so alternatives over this agrochemical are being searched. Our study focuses on the effects of expanded rice hull inoculated with selected beneficial microorganisms on growth (through agronomic characters), yield and yield components, and grain quality indices of rice. Results showed that favorable effects of different expanded rice hull preparations were not readily apparent at vegetative stage and only treatments with supplemental chemical fertilizer application were comparable with the conventional practice. Expanded rice hull combined with 50% rate of chemical fertilizer exhibited a significantly higher yield (6,471 kg $ha^{-1}$) over conventional practice (5,719 kg $ha^{-1}$). Good milling quality indices were observed in treatments having 50% chemical fertilizers plus alternatives from expanded rice hull. Finally, we demonstrated that chemical fertilizer rate can potentially be reduced into 50% if combined with expanded rice hull, and show even better output than chemical fertilizer alone.

• Proceedings of the Korean Society of Crop Science Conference
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• 2005.08a
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• pp.57-74
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• 2005

Rice yield and protein content have been shown to be highly variable across paddy fields. In order to characterize this spatial variability of rice within a field, the two-year experiments were conducted in 2002 and 2003 in a large-scale rice field of $6,600m^2$ In year 2004, an experiment was conducted to know if prescribed N for site-specific fertilizer management at panicle initiation stage (VRT) could reduce spatial variation in yield and protein content of rice while increasing yield compared to conventional uniform N topdressing (UN, ,33 kg N/ha at PIS) method. The trial field was subdivided into two parts and each part was subjected to UN and VRT treatment. Each part was schematically divided in $10\times10m$ grids for growth and yield measurement or VRT treatment. VRT nitrogen prescription for each grid was calculated based on the nitrogen (N) uptake (from panicle initiation to harvest) required for target rice protein content of $6.8\%$, natural soil N supply, and recovery of top-dressed N fertilizer. The required N uptake for target rice protein content was calculated from the equations to predict rice yield and protein content from plant growth parameters at panicle initiation stage (PIS) and N uptake from PIS to harvest. This model equations were developed from the data obtained from the previous two-year experiments. The plant growth parameters for this calculation were predicted non-destructively by canopy reflectance measurement. Soil N supply for each grid was obtained from the experiment of year 2003, and N recovery was assumed to be $60\%$ according to the previous reports. The prescribed VRT N ranged from 0 to 110kg N/ha with average of 57kg/ha that was higher than 33kg/ha of UN. The results showed that VRT application successfully worked not only to reduce spatial variability of rice yield and protein content but also to increase rough rice yield by 960kg/ha. The coefficient of variation (CV) for rice yield and protein content was reduced significantly to $8.1\%\;and\;7.1\%$ in VRT from $14.6\%\;and\;13.0\%$ in UN, respectively. And also the average protein content of milled rice in VRT showed very similar value of target protein content of $6.8\%$. Although N use efficiency of VRT compared to UN was not quantified due to lack of no N control treatment, the procedure used in this paper for VRT estimation was believed to be reliable and promising method for managing within-field spatial variability of yield and protein content. The method should be received further study before it could be practically used for site-specific crop management in large-scale rice field.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.1
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• pp.14-25
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• 2006

Response of grain yield and milled-rice protein content to nitrogen (N) rates at various growth stages is critical for quantifying real-time and real-amount of applied N requirement for target grain yield and protein content. An experiment including 10 N rate treatments at transplanting, tillering and panicle initiation stages with four rice cultivars in 2003, 6 N treatments with two rice cultivars in 2004 and 2005 was conducted. Increase of N rates at PIS significantly increased both grain yield and milled-rice protein content but increase of N rates at tillering stage significantly increased grain yield but not milledrice protein content. Therefore, high grain yield and low milled-rice protein content would be difficult to obtain only by adjusting N rates at PIS. Internal N use efficiency (INUE) was 60.5 kg grain/kg N accumulation on an average over N treatments, cultivars, and experimental years, showing considerable reduction especially at high shoot N accumulation in the experimental year of low sunshine duration. Milled-rice protein content tended to increase almost linearly with increasing shoot N accumulation, but it revealed big variation even at the same shoot N accumulation at harvest. Milled-rice protein content decreased with increasing INUE. N accumulation in the milled rice increased at an almost constant proportion of 45.5 percent of the shoot N accumulated at harvest, showing slight decresing proportion with the increasing shoot N accumulation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.1
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• pp.1-13
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• 2006

Response of grain yield and milled-rice protein content to nitrogen topdress (N) timing at panicle initiation stage (PIS) is critical for quantifying real-time N requirement for target grain yield and milled-rice protein content. Two split-split-plot experiments with three replications, one in 2004 and the other in 2005, were conducted in Experimental Farm, Seoul National University, Suwon, Korea. The experiments included three N rates at tillering stage (TS), three N timing treatments at panicle initiation stage (PIS) and two rice cultivars. The N rates at TS, N timing at PIS, and rice cultivars were randomly assigned to main plot, sub plot, and sub-sub plot, respectively. Results showed that the delayed N application at PIS reduced grain yield in 2004 and increased milled-rice protein content in both years significantly at 0.05 probability level. The calculated optimum N timing at PIS from pooled data by N rates and rice cultivars in two years was at 28 days before heading (DBH). However, real-time of N timing at PIS was dependent on plant growth and N status around PIS that in turn was dependent on applied N rates at TS. The optimum N timing at PIS was at 30 DBH for no N treatments at TS while at 27 DBH for 3.6 and 7.2 kg N/10a treatments and at 27 and 29 DBH for Hwaseongbyeo and Daeanbyeo, respectively. In general, earlier applied N at PIS resulted in lower milled-rice protein content but the highest grain yield was expected to be obtained when N topdress at PIS was applied at the time when shoot N concentration started to drop below about 23 mg/g due to dilution effect after transplanting. In conclusion, the results of our experiments imply that the currently recommended N topdress time (24DBH) at PIS in Korea should be reconsidered for the higher grain yield and the better quality of rice.

• Korean Journal of Medicinal Crop Science
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• v.19 no.4
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• pp.233-237
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• 2011

This study was carried out to investigate the seedling establishment and yield of direct-sown Platycodon grandiflorus seeds cultured by three ridge width, 0.4, 0.8, and 1.2 m and four mulching materials, rice straw, rice bran, black plastic film, and no mulching in upland. Seedling establishment rate (70%) was the highest in rice straw mulched plot of 500 seeds/$m^2$ sowed and root yield after one year was also the highest in rice straw mulched treatment and followed by rice bran, no mulching, and black plastic film treatment. In this result, ridge width 120cm and rice straw mulching combined treatment was best for getting the highest seedling establishment ratio and seedling numbers per area. However, ridge width and mulching materials should be considered soil moisture content and weed population for saving labor cost.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2001.04a
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• pp.44-46
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• 2001

Rice hull was used as a additive in order to find the effect for incresing of mushroom growth and yield in Chungnam Provincial techinical institution. 1 Treatment of 80% rice hull in small Neutaribeosut mycelial grow duration is shorter about 11 days and yield increased about 7% than conventional culture. 2. In case of Chongpung Neutaribeosut bottle culture, mycelial growth duration is shorter about two to three days in additive of 30 to 80% rice hull compared to conventional but yield similar to conventional. 3. Treatment of 30% rice hull in Agrocybe aegerita bottle culture, mycelial growth and yield increased 6days and 6% than convrntional, respectively 4 Treatment additived of 30% to 40% rice hull in Ganoderma lucidum bottle culture, similar to 454ays demand in mycelial grow duration and 38g yield/bottle in conventioal culture methods.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.2
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• pp.106-111
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• 1999

To investigate the effects of planting density and nitrogen level on growth and yield potential of newly bred heavy panicle japonica rice with large grain (Iksan 435 and Iksan 438) or many spikelets per panicle(HR14022-21-8-4 and HR14022-21-8-6), four heavy panicle type rices and two many panicle type rices(Dongjinbyeo and Donganbyeo) as the checks were planted under standard planting density (30$\times$15 cm) and dense planting density (15$\times$15 cm) with two nitrogen levels of standard nitrogen level(110 kg h $a^{-1}$) and heavy nitrogen level(165 kg h $a^{-1}$). Effective tiller rate decreased in dense planting or heavy nitrogen, when compared to standard nitrogen and planting, while leaf area index and to dry weight increased in dense planting or heavy nitrogen. Tiller numbers and panicle numbers were more increased by dense planting than heavy nitrogen, whereas spikelet numbers were more increased by heavy nitrogen than dense planting. Ripened grain ratio was slightly lower only in dense planting. 1,000 grain weight in brown rice was not significantly different in dense planting or heavy nitrogen. Milled rice yield was highest in heavy nitrogen with standard planting for heavy panicle type rice, while yield for many panicle type rice was highest in heavy nitrogen with dense planting, suggesting that many panicle type rice possesses higher adapt-ability for dense planting than heavy panicle type rice. Path coefficient analysis revealed that top dry weight, spikelet number and grain weight were the greatest positive contributors to yield, whereas tiller number was negative to yield.d.