• Korean Journal of Weed Science
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• v.3 no.1
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• pp.29-38
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• 1983

Growth habit, intraspecific competition of Digitaria sanguinalis, and interspecific competition between soybean and D. sanguinalis were evaluated to obtain the basic informations on establishing an effective control measure in upland corps. The earlier planting on April 1 produced approximately 3.5 times higher dry matter than that of the latest planting on July 22 and resulted in the earliest heading on July 8 and the latest heading was observed on September 4 planted on July. 22, but the interval between planting and heading dates was shortened progressively as the planting dates were delayed, showing irregularity of heading within a hill. Tiller numbers per plant were inhibited as densities increased from one to forty. One plant planted per pot produced significantly higher tiller numbers than density of 5 to 40 plants per pot. However, total tiller numbers was the highest in density of 40 plants planted per pot. Regardless of planting densities used, D. sanguinalis at all densities produced the similar dry matter per pot, showing severe intraspecific competition as density increased, but on each plant basis dry weight production was the highest in the lowest density such as one plant planted per pot. Competition between soybean and D. sanguinalis for the entire growing season decreased the total dry weight of soybean by 59.6%. Soybean required the maintenance of a weed free condition, about 3 to 4 weeks immediately after seeding, for obtaining the maximum yield, beyond which soybean crops effectively suppressed the growth of D. sanguinalis.

• Journal of the Korea Organic Resources Recycling Association
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• v.25 no.1
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• pp.67-78
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• 2017

The purpose of this study was to investigate the effect of humic acid on the germination, the growth and the yield of hot pepper when treated with organic hot pepper seedlings and growing season. The germination rate of 0.05% and 0.1% humic acid was higher than that of untreated, but the germination rates of 0.4% and 1.0% humic acid were 90.0% and 86.7%, respectively, compared with the control treatment (96.7%). At 30 days after transplanting, hot pepper treated with low (0.05%) or high (1.0%) concentration of humic acid decreased the growth of hot pepper seedlings, whereas 0.2% humic acid treatment significantly increased a average height (97.6 cm), leaf number (84.7) and fresh weight ($128.1g\;plant^{-1}$) of hot pepper. After 60 days of treatment with humic acid, the height of hot pepper was significantly longer in 0.2% humic acid. The mean green fruit number of 0.2%, 0.1% and 0.05% humic acid were not significantly different among the treatments, but the mean green pepper number of 0.4% and 1.0% humic acid treatments were the higher with 35.2% and 29.1%, respectively than other treatments. However, the fresh weight of green pepper was found to be $111.5g\;plant^{-1}$ more heavier than the untreated in 0.2% humic acid. The total ($5.8kg\;plant^{-1}$) and average ($1.4kg\;plant^{-1}$) fresh weight of pepper were higher than that of untreated control, except for the 1.0% humic acid treatment after 60 days of soil irrigation. The total weight of hot pepper treated with 0.2% and 0.1% humic acid treatment was $9.3kg\;plant^{-1}$ and $8.6kg\;plant^{-1}$, respectively, which were heavier than the other treatments. The effect of humic acid concentrations on soil microbial populations, pH and EC was investigated. The soil bacterial population density of 0.2% humic acid treatment was 3.5 times higher than that of untreated control soil. As the concentration of humic acid increased from 0.05% to 1.0%, pH and EC of hot pepper grown soil also increased.

• Journal of Mushroom
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• v.12 no.4
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• pp.263-269
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• 2014

Although sawdust cultivation of shiitake (Lentinula edodes) is becoming more common, it is insufficiently competitive in spring and autumn, the best time to breed shiitake. Thus, it is urgently needed to develop a technique for all year round cultivation of shiitake using mushroom growing beds. In the present study, the temperature changes according to the location of shiitake cultivation facilities were investigated. We confirmed that a refrigerator, an air conditioner, triple membranes, shiitake cultivation beds, fog nozzles which were installed in the shiitake cultivation facilities play an important role in keeping the low temperature. Bag cultivation of shiitake was tested in temperature variation from $14^{\circ}C$ to $29^{\circ}C$ with a $3^{\circ}C$ interval to know its cultivating temperature range in hot summer season. In summary, the sawdust cultivation of shiitake is possible when the temperature difference between top and bottom is maintained below $1^{\circ}C$. And the temperature of the shiitake cultivation facilities should be maintained below $23^{\circ}C$ in the induction period for fruitbody formation.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.4
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• pp.306-316
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• 2015

An experiment in a controlled environment was conducted to evaluate the genotypic differences of grain yield and yield-related elements of rice under elevated air temperature. Eight rice genotypes included in three maturing group (early, medium, and medium-late maturing group) were grown with 1/5,000 a Wagner pots at four plastic houses that were controlled to the temperature regimes of ambient temperature (AT), $AT+1.5^{\circ}C$, $AT+3.0^{\circ}C$, and $AT+5.0^{\circ}C$ throughout the rice growing season in 2011. Ripened grain ratio and 1000 grain weight showed the most susceptible and tolerant responses to elevated air temperature, respectively. The grain yield reduction was attributable to the sharp decrease of ripened grain ratio. Grain yield was significantly decreased above the treatment of $AT+1.5^{\circ}C$ and $AT+3.0^{\circ}C$ in early maturing group and the others, respectively. Highly correlation to average temperature from heading to 20 days was revealed in yield (r = -0.69), ripened grain ratio (r = -82), fully-filled grain (r = -70), and 1000 grain weight (r = -0.31). The responses of yield and yield-related elements except number of spikelets and panicle to elevated air temperature were fitted to a logistic function. The parameters of logistic function for each elements except grain yield could not be applied to the other varieties. In conclusion, yield and yield-related elements responded differentially to elevated air temperature according to maturity groups and rice varieties. Ongoing global warming is expected to decrease the grain yield not only by decreasing the grain weight but also decreasing the ripened grain ratio in the future. However, the yield reduction would be mitigated by adopting and/or breeding the less sensitive varieties to high temperature.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.2
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• pp.156-164
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• 2015

High temperature stress would affect rice production in the future as heat wave is expected to occur frequently under climate change conditions. The objective of this study was to obtain rudimentary information to assess the impact of heat stress on rice yield and its yield component in Korea. Two rice cultivars "Hwaseongbyeo" (Japonica) and "Dasanbyeo" (Tongil-type) were grown at different nitrogen fertilization levels in two seasons. These cultivars were grown in 1/5000a Wagner pot placed within four plastic houses where temperature was controlled at ambient, ambient$+1.5^{\circ}C$, ambient$+3^{\circ}C$ and ambient$+5^{\circ}C$ throughout the rice growing season in Suwon ($37^{\circ}16^{\prime}N$, $128^{\circ}59^{\prime}E$), Korea. The degree of temperature change affected grain yield whereas the level of nitrogen had little impact on grain yield. The number of panicle per pot and spikelet per panicle were not significantly different among temperature treatments in both cultivars tested. In contrast, 1000-grain weight and ripened grain ratio were decreased significantly under the treatments raising the air temperature to the level of $5.0^{\circ}C$ and $1.5^{\circ}C$ above the ambient air temperature in Dasanbyeo and Hwaseongbyeo, respectively. Reduction of 1000-grain weight and ripened grain ratio under the temperature treatments of $3.0^{\circ}C$ and $5.0^{\circ}C$ above the ambient air temperature resulted in significantly less grain yield for Dasanbyeo and Hwaseongbyeo, respectively. The greater sensitivity of grain yield to temperature increase in Dasanbyeo was attributable to the sharp decrease of 1000-grain weight and ripened grain ratio with the temperature rise above $23^{\circ}C$ during ripening period. On the other hand, Hwaseongbyeo had little variation of them in the temperature range of $23-27^{\circ}C$. These results suggested that grain yield would decrease under future climate conditions due to grain weight decreased by shorter grain filling period as well as the ripened grain ratio reduced by spikelet sterility and early abortion of rice kernel development. Thus, it would be essential to use cultivars tolerant to heat stress for climate change adaptation, which merits further studies for developing varieties that have traits to avoid spikelet sterility and early abortion of rice kernel, e.g., early morning flowering, under heat wave.

• Journal of The Korean Society of Grassland and Forage Science
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• v.8 no.2
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• pp.92-98
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• 1988

With a purpose of finding out the effects of magnesium and boron enriched organic-compound fertilizer application on the dry matter yield, yield components and changes in the botanical composition on the hilly pasture, a field experiment was arranged with five different treatments as a randomized block desigh and lasted from September, 1984 to the end of growing season in 1986. The results obtained are summarized as follows: 1. As a early plant growth and development, winter hardiness, growth vigour and coverate of grasses at the plots with organic-compound fertilizer application were better comparing to single dressing. 2. Average dry matter yields for two years were shown significantly high due to increasing amount of fertilizer. This trend was same both single and organic-compound fertilizer. And dry matter yields with organic-compound fertilizer application of low (8,693.1 kg/ha) and conventional level (12,758.7 kg/ha) were appeared to increase by 10 and 15% than those of single dressing of Low (7,930.6 kg/ha) and conventional level (11,122.6 kg/ha), respectively. But it was not significant difference. 3. Dry matter yield of grasses was significantly gained by increasing amount of fertilizer. The yield of legumes at the plots with organic-compound fertilizer application the yields of grasses were a litle more increased by 8-14%, and legumes were much more gained by 26-29% than those of the same species groups with single dressing, but it was not significant between the differnet kinds of fertilizer in the same fertilizing level. 4. At the grassland management, the rate of legumes tended to dominate at the plot without fertilization gradually. On the other hand, the botanical compositions and the rates of grasses were much better maintained at the plots with fertilization. But the rates of legumes with organic-compound fertilizer application tended to increase a little more than those of single dressing gradually. 5. All of the soil chemical properties after the experiment were much more improved comparing to before the experiment. But the average contents of soil organic matter and available $P_2O_5$ were slightly higher at the plot with organic-compound fertilization, on the other hand, pH and exchangeable cations tended to a little less than those of single dressing.

• Journal of the Korean Applied Science and Technology
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• v.35 no.3
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• pp.667-675
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• 2018

Increasing emissions regulations and demand of high-efficiency cars that travels a lot of distance with less fuel, there is growing interest in Energy Consumption Efficiency. Korean energy consumption efficiency compute combined Fuel Economy by driven city & highway driving mode and present final Energy Consumption Efficiency as using 5-cycle correction formula. Energy consumption efficiency is computed Carbon-balance-method, when used burning fuel play a key role in vehicle performance & Energy Consumption Efficiency. In Korea, vehicle fuel is circulate by Petroleum and Petroleum Alternative Business Act, there is property difference in quality standard because petroleum sector's refine method or type of crude oil. It does not appear a big difference according to fuel, because it sets steady quality standard, it may affect the performance of automobile. Thus, in research We purchase a few diesel fuel which circulated in the market in summer season though directly-managed-gas station by petroleum sector, resolve property each of fuel, we compute Fuel Economy each of them. We analyze into change depend on applying for property as nowadays utilizing Energy Consumption Efficiency calculating formula of gasoline and diesel fuel. As result, Density each of sample fuel has a maximum difference roughly 0.9%, net heat value each of sample fuel has difference 1.6%, result of current Energy Consumption Efficiency each of sample fuel has a difference roughly 1% at city drive mode, 1.4% at highway drive mode. Result of use gasoline calculator formula shows less 6% result than nowadays utilizing Energy Consumption Efficiency calculating formula, each of sample's Energy Consumption Efficiency shows maximum roughly 1.4% result in city & highway drive mode.

• Journal of Radiation Protection and Research
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• v.22 no.3
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• pp.171-181
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• 1997

A mixed solution of $^{54}Mn$, $^{60}Co$, $^{85}Sr$ and $^{137}Cs$ was applied to the soil of culture boxes in a greenhouse 2 days before transplanting red pepper and at 3 different times during its growth for investigating transfer factors ($m^2/kg-dry$) for its green and red fruits. Transfer factors varied with radionuclide, application time and harvest time by factors of about $20{\sim}100$. They decreased mostly in the order of $^{85}Sr>^{54}Min>^{60}Co>^{137}Cs$ while $^{54}Mn$ and $^{60}Co$ was higher than $^{85}Sr$ when time lapse between application and harvest was short. Transfer factors of $^{85}Sr$ and $^{137}Cs$ at the last application were lower than those at the previous one by factors of $3{\sim}20$ depending on harvest time. Variations in $^{54}Mn$ and $^{60}Co$ transfer factors with application time after transplanting were comparatively low. Transfer factors of $^{54}Mn$, $^{60}Co$ and $^{85}Sr$ mixed with topsoil before transplanting were up to $3{\sim}9$ times higher than those for the application onto soil surface 2 days after transplanting while there was no difference in $^{137}Cs$. The present results can be referred to in estimating root-uptake concentrations of the radionuclides in red pepper fruit and taking proper measures for its harvest and consumption at the event of an accidental release during the growing season of red pepper.

• Journal of Bio-Environment Control
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• v.25 no.1
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• pp.63-70
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• 2016

Water drainage from the open hydroponics often causes significant environmental pollution due to agrochemicals and loss of water and nutrients. The objectives of this study were to show the potential application of an irrigation schedule based on threshold values of volumetric substrate water content for tomato (Solanum lycopersicum L. 'Samsamgu') cultivation in a commercial hydroponic farm during spring to summer cultivation. This study was performed for minimizing effluent from coir substrate hydroponics using a frequency domain reflectometry (FDR) sensor-automated irrigation, as compared with an integrated solar-radiation (IR) and conventional timer-irrigation (TIMER) after transplanting. In results, no significant difference in daily irrigation volume was found among the treatments until 88 days after transplant (DAT). However, during the 88 to 107 DAT, the daily irrigation volume was in the order of IR (2125 mL) > TIMER (2063 mL) > FDR (1983 mL), and during the 108 to 120 DAT, it was in the order of IR (2000 mL) > TIMER (1664 mL) > FDR (1500 mL). The lowest drainage volume was observed in the FDR treatment with the order of IR (12~19%) > TIMER (4~12%) > FDR (0~7%) during the entire growing period. A lower irrigation volume in the FDR treatment after 88 DAT may be due to the sensor's detecting capacity for less water absorption by plant after completing fruit maturity with apical pruning and removal of lower leaves, while a higher irrigation volume in the IR treatment may be due to gradual increase in integrated solar-radiation amount as closer to summer season. There was no significant difference in plant growth and fruit yield among the treatments; however, a 11% and 18% of higher soluble sugar content was observed in the FDR than that of TIMER and IR treatment. respectively.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.2 no.2
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• pp.151-159
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• 1997

Benthic respiration and chemical fluxes were measured at the sediment-water interface underlying the marine fish cages floating on the open coastal waters off Tong-Young, the South Coast of Korea. The effects of cage farming on coastal benthic environment and on mass balance of organic carbon in the benthic boundary layer under the marine fish cages are addressed. In a growing season of caged fishes of June, 1995, benthic chambers and sediment traps were deployed on the sediment-water interfaces of the two sites chosen for this study: 1) Cage Site, directly underlying the fish cages of the farm at 18 m water depth, and 2) Control Site, about 100 m away from the farm at 32 m water depth. Benthic respiration rates and chemical fluxes were calculated from the evolution of dissolved oxygen and chemicals in the chamber water, and mass balance of organic carbon in the benthic boundary layer was constructed based on the vertical flux of particulate organic matter (POM) and chemical fluxes out of the sediment. High organic dumping (6400 mg C $m^{-2}d^{-1}$) and high benthic respiration (230 mmol $O_2\;m^{-2}d^{-1}$) were observed at the Cage Site. Equivalent to 40% of vertical flux of organic carbon into the Cage Site seemed to be decomposed concurrently and released back to overlying waters (2400 mg C $m^{-2}d^{-1}$). Consequently, up to 4000 mg C $m^{-2}d^{-1}$ of organic carbon could be buried into the farm sediment (equivalent to 60% of organic carbon flux into the Cage Site). At the Control Site, relatively less input of organic carbon (4000 mg C $m^{-2}d^{-1}$) and low benthic respiration rate (75 mmol $O_2\;m^{-2}d^{-1}$) were observed despite short distance away from the cages. The influence of cage farming on benthic chemical fluxes might be restricted and concentrated in the sea bottom just below the fish cages in spite of massive organic dumping and high current regime around the fish cage farm.