• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.3
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• pp.263-269
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• 1997

To cope with increasing importance of water stress in food crop production, some physiological characteristics, their cultivar-differences and grain yield of winter barley cultivars in response to water stress during reproductive stages were studied employing three covered-barley cultivars, Milyang 12, Durubori, and Olbori, one naked-barley cultivar, Baegdong, and one two-row malting-barley cultivar, Hyangmaeg. The barley grown in pot-soil was conditioned for 10 days under water stress, varying the time of water stress : 20 days before heading, 10 days before heading and the time of heading. The decrease in growth due to water stress varied greatly with the cultivars and time of water stress. The greatest injury occurred when water stress was imposed for 10 days from 10 days before heading : the culm length of water-stressed plants have shown reduced by 85∼98％ of the non-stressed; the number of spikes per plant by 52∼83%; the number of grains per spike by 71∼86%; 1,000-grain weight by 80∼84%; yield per pot by 60∼94%. The number of spikes per plant as one of yield components was most sensitively affected. As a whole, the drought resistance of cultivars was high in the order of Olbori> Milyang 12 and Durubori> Hyangmaeg>Baegdong. On rewatering the plants after termination of the water stress treatment the recovery rate of free proline content and relative turgidity of flag leaf were higher in 3 covered-barley cultivars, and lower in cultivars Baegdong and Hyangmaeg.

• Korean Journal of Plant Resources
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• v.14 no.2
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• pp.94-101
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• 2001

This study was intended to evaluate the relationship environmental condition and growth characteristics of seed treatment seed in direct sowing with different sowing date, and to suggest new cultivation model. The emergence percentage and hours were down as the delayed sowing date. Optimum sowing time was Sep. 10, and sowing must end before Sep. 20 for safety yield. When did sowing ended before Sep.20 in direct sowing cultivation, the seedling growth(SG) and No of roots of direct sowing seedling were larger than transplanting cultivation . At March 8 evaluated seedling, the SG of direct sowing seedling was higher than transplanting, and at Sep. 2(1 those were similar. The missing plant rate in transplanting cultivation was under 3 %, and that in direct sowing cultivation was about 13∼18%, and the extent were sever as delayed sowing date. The bulb fresh weight was decreased as delayed sowing, and those in direct sowing and transplanting cultivation were 230, 217g, respectively. The blot rate was high in direct sowing cultivation, and that was decreased as delayed sowing. The yield in direct sowing and transplanting cultivation were 5,134, 5,300kg, respectively, and those were decreased as delayed sowing. The average yield in early and medium-late maturity cultivars were 3,750, 4,908kg, respectively, and Sonic was highest yield in early maturity cultivars and Nongwoodego was highest in medium-late maturity cultivars. The emergence weed were 9 species as Loportea bulbifera Weddell and others, and Loported bulbifera Weddell, Digitaria violascens Link and Persicaria longiseta Kitagawa were dominant species in direct sowing cultivation with black hole vinyl mulching

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.3
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• pp.351-357
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• 1983

To study the relationships between soybean seed yield and meteorological elements, the investigation into the important agronomic characters of Bongeui cultivar and climatic factors such as precipitation, rainy days, and temperature from 1970 to 1981 was made. The results obtained were summarized as follows: 1) Coefficients of variabilities for pod-filling rate, seed yield, number of pods per plant, and seed weight were about 38%, 30%, 30%, and 5.5%, respectively. 2) Weather conditions mainly in July and August influenced soybean production. Particularly, high temperature played an important role in soybean yield reduction. 3) Correlation coefficients between maximum, minimum, or average temperature of July (and, in the case of August, maximum temperature only) and yield or seed weight, and between those of August and podfilling rate were significantly negative. 4) Regression equations between average temperature of July or maximum temperature of August and yield were Y=-42.46X +1200.86 and Y=-37.95X + 1210.42, respectively. 5) High temperature during the flowering stage affected soybean seed yield reduction significantly.

• The Bimonthly Magazine for Agrochemicals and Plant Protection
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• v.7 no.2
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• pp.6-13
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• 1986

세계인구는 매년 8천 5백만명이 증가 총49억명에 달했으며 20세기말에는 60억을 돌파할 것으로 추정된다. 인구 증가율은 다소 감소했으나 사망률이 낮아진 반면 출산율이 계속 높은 수준을 보여 세계인구는 계속 증가하는 추세이다. 이에 반하여 세계 농업생산 증수율은 인구 증가에 비하여 점차 떨어지는 실정이다. 최근 우리나라의 식량 자급율(自給率)은 50$\%$를 밑돌고 있는 형편이다. 더구나 근래에 와서 세계적 기상이변(氣象異變)으로 특히 아프리카의 수단과 같은 나라는 수년간 한발(旱魃)이 계속되어 수백만의 사람들이 굶어 죽거나 굶주리고 있는 상황이다. 이와 같은 인구 증가에 따른 식량의 확보(確保)와 농산물의 증산(增産)은 이용 가능한 농경지(農耕地)가 제한되어 있는 한 단위 면적당(單位 面積當) 수량(收量)을 높이는 수 밖에 없다. 이 목적을 달성시키기 위하여는 품종개량(品種改良), 경종법(耕種法) 개선 등 여러 가지 방법을 들 수 있으나 그 중에서도 가장 간편하고 효과가 큰 방법으로는 병$\cdot$해충$\cdot$잡초(病$\cdot$害蟲$\cdot$雜草)의 피해(무방제시의 감수율 $40\sim60\%$)를 막아 수량을 올리는 것이다.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.465-468
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• 2008

This study investigated the best condition when mixed sand with a river and crushed sand was used though the experiment for the properties of the concrete corresponding to the control of fine aggregate ratio to apply the mixed sand and properties of the fine aggregate at the ready-mixed concrete factory on Yeongnam and Honam. The physical properties of Yeongnam and Honam is satisfied with KS F 2526 and KS F 2527 except fineness modulus and passing amount of 8mm sieve. And, the mixed sand above two types which were incongruent to use individually was being used at each factory, and it was managed in accordance with KS. The flowabillity of the mixture proportion of concrete which was estimated by method of unit volume weight according to the fine aggregate ratio at each factory on Yeongnam and Honam was higher than existing mixture proportion. It was analyzed that the residual water due to decline of the surface area caused by reducing fine aggregate ratio was increased relatively. Accordingly, it was considered that the effect on the economic mixture proportion and improvement of durability might be possible.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.3
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• pp.224-232
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• 2017

In this study, we investigated the disease, insect damage, growth, and yield characteristics of sorghum and foxtail millet in an organic paddy-upland rotation system at Anseong-si Gyeonggi province, Korea, in 2016. Seven varieties of sorghum and foxtail millet are used in this study. A rotational upland field and continuously cropped upland field were compared in order to establish an optimum cultural method and to select the best sorghum and foxtail varieties for a paddy-upland rotation system. The incidence rate of major diseases was higher for sorghum than for foxtail millet. Moktaksusu (22.8%) had the highest incidence rate among sorghum varieties. Hwanggeumchal (7.0%) had the highest incidence rate among foxtail millet varieties. DS202 (89.3%) was the most severely damaged by Ostrinia furnacalis larva, which is the main pest of sorghum and maize. The weed numbers, and the weed fresh and dry weights were lower in the rotational upland field than in the continuously cropped upland field. Futhermore, the number of weed plants decreased by 42% and the dry weight of weeds decreased by 33% in the rotational upland field compared to the continuously cropped upland field. The culm length of sorghum and foxtail millet were 7.9 cm, and 3.4 cm longer, respectively, in the rotational upland field than in the continuously cropped upland field. The average yield of sorghum per 10 a increased by 90% in the rotational upland field compared to continuously cropped upland field. However, there was no significant difference between the rotational upland field and the continuously cropped upland field for foxtail millet. The most suitable varieties for a paddy-upland rotation system were judged to be Hwanggeumchal, Donganmae, and DS202 for sorghum, and Samdachal, Samdamae, Dahwangmae for foxtail millet.

• The Bimonthly Magazine for Agrochemicals and Plant Protection
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• v.4 no.1
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• pp.64-71
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• 1983

• Korean Journal of Weed Science
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• v.12 no.1
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• pp.16-30
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• 1992

A field experiment was done to evaluate the growth response, rhizobia nodulation and vesicular-arbuscular mycorrhizal fungi (VAMF) infection of soybean treated with the different concentration of three-herbicides, alachlor, simazine, linuron. The results obtained were summarized as follows ; Emergence rate of soybean was non-significantly decreased by increasing the herbicide concentration. In simazine treatment, low emergence rate showed even in recommended concentration, especially the lowest emergence rate in treble concentration of recommended dose was about 50%. The plant length of soybean lowered by increasing the herbicide concentration, but there were almost no differences in recommended dose. Particularly that in a high concentration of herbicides at three weeks after treatment(WAT) was decreased remarkably. In the plant diameter of soybean shoot, no differences in the recommended concentration of alachlor and linuron at 2 WAT, but those of recommended dose was decreased with the lapse of time, and the lowest treatment was simazine-treated plot. Leaf area and fresh weight of soybean tended to decrease over the control even in recommended concentration and it was decreased with the increment of the herbicide dose. Yield component, fresh weight of rhizobia nodule and chlorophyll content of soybean leaves were reduced with the increment of herbicide dose, espicially remarkable tendency was revealed in simazine-treated plot. Seasonal infection rate of VAM showed a slight decrease by increasing of herbicide dose, and the lowest infection was simazine treatment. Significant correlation was realized among the reduction of rhizobia nodulation, VAM colonization and the agronomic characters of soybean and it was considered that the reduction of rhizobia nodulation and VAM colonization by misapplication of the herbicides might be a causal factor for decrease in soybean yield.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.21 no.2
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• pp.250-257
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• 1976

Defoliation effect of two soybean cultivars on the grain yield was studied under different planting densities planted at two different planting date. Leaf removal caused a linear decrease of grain yield with increased amounts of defoliation in the case of lower population densities, while in the case of higher population densities over 40 plants per sqare meter, the slight removal of lower leaves indicated increased grain yields by 13% to 35% compared with control depending on the cultivar and planting time. The pod number per plant was the most effective factor influencing grain yield. The grain weight and the percent of matured grain become more important components for higher yield with decreased population densities depending on cultivar.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.22 no.2
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• pp.1-17
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• 1977

Nitrogen responses to yield and other agronomic characters were studied using four rice varieties, Tongil, Jinheung, Milyang 23, and Yushin, at six nitrogen levels, 0, 10, 15, 20, 25 and 30kg/10a, in a silt loam soil at the Crop Experiment Station, Suweon, Korea, in 1976. Grain yields of Milyang 23 and Tongil were much higher than those of Jinheung and Yushin at high nitrogen levels (15-30kg/10a). Optimum nitrogen levels of the rice varieties, Tongil, Milyng 23, Yushin, and Jinheung, estimated by intersecting straight line, were 22, 19, 19, and 12kg/10a, respectively. Morpshological characters, dry matter production before and after heading, and yield components were dicussed in relation to the nitrogen responsivenees of the rice varieties. In addition, relationships between yield, yield components, and other agronomic characters were discussed to obtain some informations for higher rice yield.