• Current Research on Agriculture and Life Sciences
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• v.23
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• pp.1-8
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• 2005

The purpose of this study was carried out to determine the optimum sowing date and days after sowing (DAS) in automatic facility located at Uiseong of Gyeoungbuk province. The seedling height was rapidly increased with a delay of sowing time from April to May. The 10-day old seedlings with suitable plant height (> l0cm) for machine transplanting in the facility were obtained when the seeds sowed after May 20 at Uiseong in Gyeoungbuk province. The dry weight-height ratio of 10-day old seedlings was significantly decreased when the seeds sowed after June 20, and 15-days old seedlings did after May 10. No. of panicles/hill was reduced with increasing of days after seeding. But there were no significant difference among other yield components such as no. of grains/panicle, ratio of ripened grains, and 1,000 grain weight. The highest grain yield, 748kg/10a, was attained from the 10-day old seedlings transplanted at May 27 in comparision with those of 15-day and 20-day old seedlings. The grain yield of 10-day old seedlings transplanted at June 26 was also higher than that of 15-day old seedlings.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.3
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• pp.216-222
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• 1994

Experiments were conducted in the research field of the former Wheat and Barley Research with three barley cultivars, Olbori, kangbori and Suwon 18, which show different growth characteristics. Relationships between the degree of grain filling and the functions of photosynthetic organs in grain growth post-anthesis were investigated by removal treatment of awns and leaves, Stems and leaf sheath contributed to final grain weight invariably with cultivars by 79.2∼81.4%. while the contribution rate of awns and leaf blades varied by different cultivars, Awns contributed by 11.6∼13.8% in 'Olbori' and 'Kangbori', and 5.4% in 'Suwon 18', Contribution of leaf blades was 15.4% for 'Suwon 18', and 4.8∼8.1% for other cultivars, Of leaf blades upper ones showed a higher contribution rate, Early-maturing cultivars which maintain leaf greenness to the late phase of grain growth or awned cultivars were considered advantageous in grain filling.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.1
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• pp.123-130
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• 1996

Experiments were conducted to effect of seeding rates and growth regulator (KIM-112) application on lodging resistance and yield in direct seeding on flooded paddy surface. The number of seedlings per $m^2$ were ranged from 61 to 143, and seedling ratios were from 71.7 to 76.1％. The culm length was increased with the higher seeding rates. The culm length was significantly shortened by KIM-112 application, and the shortened effect of internodes were various with application times. The leaf angles with the culm and top leaves were errected and position of light reception by KIM-112 application, also the weight of culm base was increased. The bending moment at breaking of culm and culm diameter were decreased according to the higher seeding rates. The number of panicles per $m^2$ were increased according to the higher seeding rates. The ripened grain rate and 1, 000 grains weight became higher than the untreated control.

• Research in Plant Disease
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• v.19 no.3
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• pp.196-200
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• 2013

This study was carried out to investigate yield loss due to soybean leaf spot disease caused by Cercospora sojina Hara and to determine the economic threshold level. The investigations revealed highly significant correlations between disease severity (diseased leaf area) and yield components (pod number per plant, total grain number per plant, total grain weight per plant, percent of ripened grain, weight of hundred seed, and yield). The correlation coefficients between leaf spot severity and each component were -0.90, -0.90, -0.92, -0.99, -0.90 and -0.94, respectively. The yield was inversely proportional to the diseased leaf area increased. The regression equation, yield prediction model, between disease severity (x) and yield (y) was obtained as y = -3.7213x + 354.99 ($R^2$ = 0.9047). Based on the yield prediction model, economic injury level and economic threshold level could be set as 3.3% and 2.6% of diseased leaf area of soybean.

• Research in Plant Disease
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• v.7 no.3
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• pp.150-154
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• 2001

The relationships between the weather conditions and the occurrence of rice bacterial grain rot caused by Burkholderia glumae during the rice heading period, were examined by analying the data accumulated from 1992 through 2000 and by conducting greenhouse and field experiment to develop a model far forecasting the disease. The disease severely occurred in 1994, 1995, 1998, and 2000, when it was high in temperature and rainfall during the heading period of middle-late rice varieties. While it occurred weakly in 1993 was high in rainfall and low temperature and it was reversely in 1997. When treated under wetting condition (above the 24-hour)after inoculation at heading period, the infection rate increased as the inculum concentration increased, it was 86.1% at 10$^{8}$ cfu/ml. When under drying condition, the disease of 12.5% occurred only at $^{8}$ cfu/ml. On the other hand, 1,000 grain weight and the percentage of ripened grains remarkably decreased as the infection rate increased.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.3
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• pp.218-226
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• 1984

This study was conducted to establish fundamental of cultivation system in the southern warm region of Korea by investigation of variation of yield component and yield under the different nitrogen fertilizing levels. And that levels in this experiment were 10, 15, 20 and 25 Kg/10a. Optimum fertilizing level of nitrogen was 20 kg/10a in Seokwang variety and 25 kg/ 10a in Dongjin variety. On the optimum fertilizing level (Seokwang; 20 kg/10a, Dongjin; 15 kg/10a), the correlation coefficient between No. of panicles per unit area and the rate of ripened grains were showed negative correlation (Seokwang; r =-0.6023$\^$*/, Dongjin; r=-0.858l$\^$**/). In the primary, secondary branches and spikelets, the degeneration ratio was increased significantly under the level of N=25 kg/10a in Seokwang, N$\geq$20 kg/10a in Dongjin. In Dongjin, the rate of ripened grains was decreased with increase in nitrogen fertilizing levels and that caused to decrease the yield.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.1
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• pp.7-14
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• 1985

Lodging damage of Sesame was different between growing condition and variety although same wind velocity. The result of lodging damages showed variation of leaves area. stem length, capsule numbers and yield in late-varieties but showed variation of capsule setting length, dry weight of leaves, main root length, ripening rate of grain in early-varieties. Specially late varieties showed decreasing character of significant coefficient in mono, and after-barley-cropping at lodging degree of 30 commonly.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.4
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• pp.332-339
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• 1991

본 시험은 1968-1990년까지 23년간을 동일시험구에서 무비구를 비롯하여 무질소구, 무인산구, 무가리구, 3요소구, 3요소+유기물구(퇴비 또는 생고), 3요소十석회구를 설치하고, 1990년수도품종 ‘진흥’을 공시하여 그 수량생산성과 미질의 외관 및 이화학적특성을 조사하므로써 장기간에 걸친 시비법이 수량과 양질미생산에 미치는 영향을 검토한 바 그 결과를 요약하면 다음과 같다 1 수량생산성은 3요소구에 비해 3요소+유기물구에서 3-7%의 증수효과가 있었으며, 1 증수요인은 수수와 1수당입수의 증가였다. 2. 무가리구의 수량은 85%로 등숙률의 저하가 감수요인이며, 무인산구는 74%로 수수의 감소가 감수요인이며, 무질소구와 무비구는 59-33%로 수수와 1수립수의 현저한 감소가 감소요인이었다. 3. 미질의 외관적 특성은 무비, 무질소, 무인산구에서 수량은 크게 낮은 반면에 완전미율이 높고 동할미, 심복백미율이 현저히 적으며 3미립의 투명도도 높아 양질의 외관을 보였다. 이에 대해 고수량을 보인 3요소＋유기물구(퇴비, 생고)에서 완전미율이 낮고 동할미, 심복백미율이 높고 투명도가 낮아 외관적 미질이 저하하는 경향이었다. 4 미질검정으로 이용되고 있는 물리적 특성인 알칼리붕괴성과 gel consistency는 처리간 차이를 인정할 수 없었다. 5. 식미의 량부로 평가하고 있는 미립의 화학적 특성은 처리간 차이를 인정할 수 있었다. 즉 단백질함량은 3요소＋유기물구에서 높고 무비구에서 낮았으며 Mg, Mg/K, Mg/KㆍN, Mg/KㆍN\ulcornerAmylose는 무비, 무질소, 무가리구에서 높고, 3요소+유기물. 3요소+석회구에서 낮았다 6. 이상과 같은 결과로 미루어 본 실험에 시용된 절대질소량은 많지 않음에도 불구하고 3요소＋유기물구는 유기물 분해에 따른 질소의 추비적 효과가 나타나서 무비, 무질소구에 비해 동할미, 심복백미 등 미립의 외관적 특성을 저하시키고, 단백질함량은 높이고 Mg/K\ulcornerNㆍAmylose를 낮추어 식미를 저하시키는 것으로 해석된다 7. 취급특성으로서의 흡수율, 취급액요드정색도, 취급용액출고형물은 처리간 명백한 경향을 발견할 수 없었다.

• Korean Journal of Organic Agriculture
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• v.19 no.3
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• pp.397-404
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• 2011

This experiment was performed to study growth and yield of rice (cv. Dongjinbyeo) and soil properties affected by the application of rice straw, compost, and hairy vetch. An application of rice straw and compost led to the decrease in plant heights and tillers compared with chemical fertilizer whereas hairy vetch application resulted in slight increase. Panicle no per plant was the highest in chemical fertilizer and there was no difference among organic matters. Grain per panicle was no difference among chemical fertilizer, rice straw, and compost whereas was the lowest in hairy vetch application. The 1,000 grain weights did not show any statistic difference and the ripened rate was enhanced in all treatments of organic sources compared with chemical fertilizer. Therefore, an index of rice yield of compost, rice straw, and hairy vetch to chemical fertilizer (100%) was 77, 72, and 103%, respectively. In addition, an application of organic sources led to the increase of soil pore space and this contributed to the improvement of soil physical property.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.2
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• pp.215-223
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• 1987

This experiment was carried out to determine the effect of nitrogen application on the cold tolerance of rice plant, with treatment of three levels of nitrogen and three times of application under the low temperature at tillering and panicle initiation stages. The higher cold tolerance variety was increased in plant height and number of tillers on high nitrogen level during the low temperature treatment. Nitrogen content of leaf blade was increased, but carbohydrate content was decreased during the low temperature treatment at tillering stage. Ethylene evolution from leaf was remark-ably increased just after low temperature treatment. Highly significant negative correlation was observed bet-ween the nitrogen content of leaf blade and percentage of filled grain under low temperature condition at reproductive growth stage.