• KOREAN JOURNAL OF CROP SCIENCE
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• v.19
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• pp.25-31
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• 1975

In order to increase the rate of ripening during the grain-forming stage the partial dressing was introduced with the ordinary dressing comparatively. Two different rice varieties, Bong-kwang(early) and Nong-kwang (moderate), grown at the fine sand alluvial soil of River, Han Kimpo, were investigated. To evaluate the photosynthetic ability of these treatments assimilation rate of Carbon-14 was effectively carried out with the active leaves of rice at the maturing stage, and the inorganic constituents of leaves, stem, leaf sheath and grain were analyzed. All the data on the photosynthetic ability, inorganic constituent and yield determining were discussed with the point of continual phloem translocation between those plant organs.

• Membrane Journal
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• v.9 no.4
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• pp.209-214
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• 1999

The purpose of this research was to investigate the permeation properties of each stage in three stage reverse osmosis system for cold-mill wastewater reuse. After construction of the three staged pilot plant which had 75% recovery and equipped with seven plate-and-frame modules, the change of each stage's penneate flow and quality were investigated in the process of membrane fouling. The order of average permeate flow was first, second, and third stage at the beginning. As the operation time passed, the permeate flow of first stage was decreased, the second stage was maintained steadily, and the third stage was increased. Accordingly, the fouling was initiated at the first stage and then progressed to the second and third stage. The first stage's permeate quality showed the best and the second and third stage was the next in that order. And the order of quality was maintained during the test periods. Therefore, the permeate quality was not affected by membrane fouling.

• Korean Journal of Plant Resources
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• v.16 no.3
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• pp.207-211
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• 2003

In an effort to produce high quality Curcuma aromatica Salisbury in the southern area of Korea, a variety of shade­method was used to prevent withering during the summer. The experimental results are summarized as follows. The effect of shading on emergence of Curcuma aromatica Salisbury rhizome was none or very little. The effect of shading on the growth and development of Curcuma aromatica Salisbury was the highest under a shade rate of 15­30％. In this case the size of the plant height was the biggest and loaves the largest, thus showing the best condition for plant growth. The growth of rhizome under a shade rate of 15％ was more active than that without shading. The weight of rhizome in this case was the largest, and thus showing the best condition for rhizome growth.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.517-517
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• 2016

최근 기후변화로 인해 하천 건천화가 빈번히 발생함에 따라 농업용 저수지로부터 하류 하천유량을 얼마나 공급할 수 있으며, 어느 시기에 공급하는 것이 적당한가에 대한 의문이 발생하고 있다. 본 연구에서는 농업용 저수지의 하천유지용수 공급에 대한 관점에서 용수배분을 자유롭게 모의조작 할 수 있는 모듈을 개발하였고, 이를 미호천 중류의 북일 수위관측소 유역 내 위치한 저수량이 100만 $m^3$인 농업용 저수지 9개소를 대상으로 적용하였다. 관개용수량은 작물증발산량, 담수심, 침투량, 손실율 등을 고려하여 산정할 수 있도록 하였으며, 하천유지용수 공급량은 기준갈수량을 기본값으로 하였다. 또한 하천유지용수의 공급방식은 무공급, 비관개기 공급, 연중 공급, 운영률에 의한 공급의 4가지로 구분하여 일괄적인 모의가 가능하도록 구성하였다. 기상청 RCP 8.5 기후변화 시나리오를 이용하여 미래 모의기간에 대한 유역 말단부의 갈수기 하천수량 변화와 유황패턴을 분석한 결과는 다음과 같다. 첫째, 하천유지용수을 비관개기에 공급하는 저수지 운영으로 하천수량은 하천유지용수를 공급하지 않는 저수지 운영보다 연평균 1.8백만(2.0%) $m^3$ 증가, 연중 공급하는 저수지 운영보다 4.3백만$m^3$(4.7%) 증가, 운영률에 의해 하천유지용수를 공급하는 운영은 연평균 13.1백만(14.6%) $m^3$ 증가하였다. 둘째, 하천유지용수를 비관개기에 공급하는 저수지 운영은 갈수기로 갈수록 유량이 증가하였다 감소하는 것으로 나타났다. 하천유지용수를 연중으로 공급하는 저수지 운영은 비관개기에 공급하는 저수지 운영보다 갈수량(Q355) 이하의 유량을 더 증가시킬 수 있는 것으로 분석되었고 풍수량(Q95)과 평수량(Q185) 사이의 하천유량이 상대적으로 크게 증가하였다. 운영률에 의해 하천유지용수를 공급하는 저수지 운영은 하천유지유량을 공급하지 않는 저수지 운영방식보다 하천유량의 증가와 갈수기 전반에 걸쳐 유황이 안정되는 것으로 분석되었다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.5
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• pp.95-102
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• 2022

Recently, there has been a growing interest in reducing greenhouse gases in all industrial fields. In the construction industry, studies have been conducted for the use of high-volume fly ash concrete to replace cement with fly ash. Quantitative measurements of cement hydration and fly ash reactivity enable a clear understanding of the strength development mechanism of high-volume fly ash concrete. It is very difficult to describe the reactivity in a simple way because the hydration and pozzolanic reactions of cement paste containing fly ash are very complex and the composition of the hydration product cannot be accurately determined. This study investigated the hydration and mechanical properties of high volume fly ash (HVFA) cement according to the substitution rate of fly ash (FA). The hydration degree of cement and the reactivity of FA were evaluated through the selective dissolution method and the non-evaporable water content of the paste according to age. In addition, compressive strength was measured using HVFA mortar specimens according to age. As a result of the experiment, as the substitution rate of fly ash increased, the hydration degree of cement increased, but the reactivity of FA decreased.

• Korean Journal of Agricultural and Forest Meteorology
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• v.4 no.1
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• pp.38-48
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• 2002

This study examines the relationships between atmospheric influences and grain yields including yield components as well as growth stages. Data used in this study were collected from the long-term field experiment at Suwon for the period between 1974 and 2000. Mean grain yield of barley cultivar, Olbori, for the recent 14 years(1987∼2000) with warm winters was higher by 0.42 ton per hectare than that for 27 years(1974∼2000) at Suwon as a result of the higher numbers of spikes per unit land area and grains per spike. However, the 1000-grain weight decreased by about 0.6 gram. Mean first day of regrowth for the recent 14 years was earlier by five days than that for 27 years. Also, beginning date of regrowth was positively correlated with that of heading and ripening. Mean period of ripening for the years of 1987 through 2000 was similar to that for 27 years, but mean period of overwintering was shorter by nine days than that for 27 years. On the other hand, mean periods of seedling and tillering were longer by three days than those for 27 years. Meteorological elements at various growth stages affecting grain yield of winter barley were air temperature (positive correlation) and sunshine hour (negative correlation) of overwintering stage, precipitation (negative correlation) of tillering stage, and potential evapotranpiration (positive correlation) of tillering stage. The 1000-grain weight was not significantly correlated with the meteorological elements. Culm length was negatively influenced by high temperature and dry weather situations during the ripening period, but spike length was positively influenced. Overall, it was found that grain yield of barley, cultivar Olbori, was iufluenced by meteorological elements of overwintering, tillering, and ripening stages.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.3
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• pp.207-211
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• 1996

This study was conducted in the sandy loam soil to find out the effects of fly ash and zeolite applications on saving of irrigation water which was required great quantities during the cultivation days of dry seeded rice. Total water loss was reduced so rapidly in the early growth stage that n was the least in the 18th day after irrigation. After that day it was increasd due to the growth development and the rising temperature. In the daily mean of decreasing water level during the whole irrigation days, control was 47.7mm but the treatments of fly ash and zeolite were 31.8mm and 35.8mm respectively Amounts of the presumed irrigation water of fly ash and zeolite treatments were lower about 29.1% and 20.9%. respectively than that of control during the whole irrigation days These gaps between control and amendment treatments were greater in the early growth stage than in the late stage Hardness, bulk density and the ratio of solid phase in the soil after experiment were the highest in the fly ash treatment and those of control and zeolite treatments were showed the same trends each other. Amounts of water percoration of control and zeolite treatments in the soil were increased 8.2% and 2.6% respectively in comparision with those in the soil after amendment application, but that of fly ash treatment was decreased 42.5%, In contrast to the water percoration of control in the soil after experiment, those of fly ash and zeolite treatments were decreased 76% and 32%.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.3
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• pp.293-298
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• 2014

This study conducted experiments on the reclaimed land of Saemangeum located in Jeongrabuk-do in order to gain basic information about growth characteristics and yield ability according to soil salinity. Having soil excluding salt as a control group, this study adjusted the specimens' soil salinity to level 4 and then planted four varieties including Ilmichal Corn to investigate the growth or grain yield according to salinity. About the corn establishment rate according to soil salinity, over 97% up to $3.2dS\;m^{-1}$ was established, and then, it was reduced gradually according to the increase of concentration. According to the salt concentration of soil more required growth duration from seeding to heading comparing to non-treatment salt was delayed, at $1.6dS\;m^{-1}$, two days were delayed, at $3.2dS\;m^{-1}$, four to six days were delayed differently by varieties, and at $4.8dS\;m^{-1}$, six to 10 days were delayed. About the plant fresh weight according to soil salinity, Chalok 4 and Eolrukchal indicated 93%~97% or so compared with the salt-free one at $1.6dS\;m^{-1}$, and Chalok No. 4 showed 79% at the salinity of $3.2dS\;m^{-1}$, too, and it was a relatively higher growth percentage than those of the other varieties. In terms of dried seed weight according to soil salinity, compared with the corns cultivated in the control group, averagely 12.1% was lowered at the time of cultivation at $1.6dS\;m^{-1}$, and $3.2dS\;m^{-1}$ 40% was lowered, and about 70% was lowered at $4.8dS\;m^{-1}$. According to the result of examining the point of time that dried seed start to reduce due to soil salinity with the regression equation, soil salinity which starts the reduction of grain weight is $1.67dS\;m^{-1}{\sim}2.18dS\;m^{-1}$, and it differs by varieties, and EC of 50% that the yield reduces in half is $2.96dS\;m^{-1}{\sim}4.45dS\;m^{-1}$. And the degree of influence on each of the growth factors according to soil salinity is founded to be in the order of establishment rate

• Journal of The Korean Society of Grassland and Forage Science
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• v.32 no.2
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• pp.149-156
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• 2012

his experiment was carried out to evaluate the effects of nitrogen top dressing levels on the growth, feed value, and anthocyanin content for developing functional feed of colored barley. A colored barley cultivar, Boanchalbori, was tested in this experiment. Nitrogen top dressing levels was six (0, 20, 40, 60, 80, 100%) and top dressing time was a regeneration time. In case of productivity, heading data was get behind and dry matter rate was significant decreased with higher nitrogen top dressing levels (p<0.05). Fresh yield, dry matter yield and TDN yield was increased with higher nitrogen top dressing levels, but not significant. In case of feed value, crude protein content was significant increased with higher nitrogen top dressing levels (p<0.05), and higher in the order of spike, whole and leaf culme of the plant. Percent NDF and ADF was decreased with higher nitrogen top dressing levels in leaf culme, but no difference in spike and whole (p<0.05), and higher in the order of leaf culme, whole and spike of the plant. TDN was increased with higher nitrogen top dressing levels in leaf culme, but no difference in spike and whole (p<0.05), and higher in the order of spike, whole and leaf culme of the plant. Total anthocyanin content was significant decreased with higher nitrogen top dressing levels in leaf culme and whole (p<0.05), and higher in the order of leaf culme, whole and spike of the plant. Specially, cyanidin-3-glucoside (C3G), delphinidin (Del), malvidin-3-glucoside (M3G) and malvidin (Mal) show a significant decrease. So there are an accumulation of anthocyanin in the culm, and standard nitrogen top dressing levels dressing on the regeneration time for produces high anthocyanin content of the colored barley.

• Journal of Practical Agriculture & Fisheries Research
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• v.22 no.2
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• pp.89-97
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• 2020

This experiment was conducted at Sancheong from 2013 to 2015. The objective of this study was to establish the seeding rate, and to clarify the optimum nitrogen fertilizer level for rye seed production in the southern area of Korea. We employed Korean rye cultivar 'Gogu' in this test. The experimental design was a split-plot design with three replications. A split-plot design was used with three seeding levels (3, 5, and 7 kg 10 a^-1) on the main plots and other treatments fully randomized in sub-plots. A factorial arrangement of treatments included three different nitrogen fertilizer levels (0, 3, 6, and 9 kg 10 a^-1). The grain yields of rye affected by increasing the seeding rate. The number of spike per m² and immature grain weight was increasing, while the fertility rate and the number of grain per spike were decreased as seeding rate were increased from 3 kg 10 a^-1 to 7 kg 10 a^-1. The percentage of a productive tiller, 1-liter weight, and 1000-grain weight also decrease by increasing seeding but the grain yields of rye had less effect. There was an increase in the number of spike per m², the number of grain per spike, and grain yields as nitrogen fertilizer level was increased from 0 kg 10 a^-1 to 9 kg 10 a^-1 and followed a delaying heading and an increasing lodging of the plant. But grain yields did not affected by the interaction of seeding rate × nitrogen fertilizer levels. The best seeding rate and nitrogen fertilizer level for rye seed production were 5 kg and 3 kg 10 a^-1, respectively, considering seed and fertilizer reduction and the prevention of pollution by excess fertilization.