• Journal of Microbiology
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• v.39 no.3
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• pp.195-201
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• 2001

The effect of moisture content an the reductive dechlorination of polychlorinated biphenyls and population dynamics of dechlorinating microorganisms was investigated in sediments spiked with Aroclor 1248. In sediment slurry with an overlying water layer, dechlorination ensued after a 4-week lag period and reduced the average number of chlorines per biphenyl from 3.91 to 3.15 after 48 weeks. In the sediments of reduced moisture content, however, dechlorination occurred after a lag period of 12 weeks and decreased the average number of chlorines per biphenyl to only 3.62, and the dechlorination rate was also slower. When the population size of dechlorinators, methanogens, and sulfate-reducing bacteria was determined by the most probable number techniques, however, no difference was found between the slurry and the low-moisture sediments, except for methanogens. The growth of dechlorinating populations coincided with the end of the lag period and they then increased by 3 orders of magnitude in two conditions. Specific growth rate of dechlorinators showed little difference between the slurry and the low-moisture sediments; however, growth yield was high in the sediments of reduced moisture content. The reduction of sediment moisture decreased the dechlorination rate and extent of PCBs but did not inhibit the growth of PCB dechlorinators.

• Journal of the Korea Organic Resources Recycling Association
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• v.22 no.3
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• pp.11-22
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• 2014

The buffer capacity of food waste lowers during the collecting and transportation period. Food waste usually shows deficiency of micro nutrients especially molybdenum(Mo) and cobalt(Co). Therefore, food waste can be considered as a good mixture of livestock waste to enhance methane production. The objective of this study was to investigate the correlation between properties of substrates (local food waste and livestock manure) and methane yields for successive anaerobic fermentation process and its stable management. Food wastes were taken at an intermediate storage or treatment system provided by eight local authorities (Gangnam, Gangdong, Gwanak, Guro, Dongjak, Songpa, Yeongdeungpo, and Younsan) in Seoul. The solid content and potential methane yield of food wastes were average of 16% and $446.6STP-m{\ell}/g-VS$ (range from 334.8 to $567.5STP-m{\ell}/g-VS$) respectively. As for the beef cattle manure, the solid content and potential methane yield had an average of 26% and $280.6STP-m{\ell}/g-VS$ respectively. Potential methane yield had a positive correlation with fat content, and hydrogen content and a negative correlation with carbohydrate content ($r^2>0.8$). Therefore, the potential methane yield can be predicted based on the substrate characterization results with reasonable accuracy. Further research may be needed to investigate the relation of the properties of the mixture substrate and methane production rate. The mixtures may include food waste, livestock waste, and bulking agents (saw dust, rice hull, or agricultural byproducts etc.) to determine best combination of these substrates for maximum methane production rate.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.1
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• pp.45-54
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• 2002

Ninety lactating goats (Bachthao, Barbary, Beetal and Jamnapary breeds) were used in an experiment to investigate the replacement value of the tree fodders Flemingia (Flemingia macrophylla) and Jackfruit (Artocarpus heterophyllus). The foliages were used to replace the concentrate in diets based on chopped whole sugar cane (Sacharatum sp.), Para grass (Brachiaria mutica) and dried cassava root (Manihot esculanta). The concentrate was replaced by foliage of Jackfruit or Flemingia at 0%, 20%, 40%, 60% and 80% based on the crude protein (CP) content in the concentrate and foliages, respectively. Average milk yield was 1,617 g/day for goats fed Jackfruit compared to 1,532 g/day for those fed Flemingia. Increasing amounts of Flemingia foliage resulted in reduced dry matter intake and decreased milk yield but milk composition (CP, casein and fat content) was similar up to 60% replacement. Flemingia showed a poor potential as a supplement for lactating goats and replacement levels should not exceed 20% of the protein in the concentrate or 7.5% of the dry matter in the diet. With respect to the combination of milk production and net return over the control a CP replacement rate of 20% was the most promising. For Jackfruit there was similar feed intake and milk yield at a replacement level of 20% of CP in the concentrate (9.2% of DM intake) compared to the control diet. Milk yield at the level of 40% replacement (15% of the DM) in the diet was slightly reduced. Up to a level of CP replacement rate of 60% (21% DM in the diet) can be suggested for on-farm testing as a higher net return over the control was obtained on station.

• Journal of The Korean Society of Grassland and Forage Science
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• v.10 no.2
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• pp.102-109
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• 1990

This experiment was carried out to study the effect of pure mineral nitrogen fertilizing on dry matter yield of grassland and the advisable mineral nitrogen amounts in long duration under practical conditions at the "Federal Institute for Agriculture in the Alps" in Austria. The application rates were 0, 30, 60,90 and 120 kg N/ha/cut, the cutting regimes 3-, 4-, 5- and 6-cuts/year. In order to explain the nitrogen-profitability were determined that 1 kg pure mineral nitrogen have to produce 8 - 16 kg DM/kg N in dependence on cutting regimes and requiring of nitrogen efficiencies. The results were as follows: 1. With only PK-fertilizaing average dry matter yields from 4.0 to 7.6 tons per ha and year were obtained. 2. Within all applied cutting regimes 60 kg min. Nlhalgrowth have proved to be the most efficient application rate witn 13 - 24 kg DM/kg N in dependent of cutting regimes. Comapred with only PK-treatment the DM yields increased by 3.9 - 4.7 t/ ha nad year. 3. By the sigmaformed process of Input-Output curve the highest marginal yield (the "most efficient" Ndressing rate) per ha and year was calculated: 152 kg N at 3-cut regimes, 204 kg N at 4-cut regimes, 220 kg N at 5-cut regimes and 240 kg N/ha/year at 6-cut regimes. 4. With required efficiencies of 16 and 12 kg DM/kg N 240 - 300 kg N per ha and year respectively would have to be applied at 3-cut regimes; with required efficiencies of 12 and 10 kg DM/kg N at 4-cut regimes the appropriate figures ranged from 320 to 420 kg N/ha and year, at 5- and 6-cut regimes and efficiencies of 10 and 8 kg DM/kg N results of 360 - 460 kg N and 380 - 500 kg N respectively were obtained. 5. At the relatively dry location Piber the highest dressing rates were needed in order to obtain the efficiencies from 8 to 16 kg DM/kg N, about 30 - 60 kg N/ha/year more than at the relatively moist location Admont.ist location Admont.

• Animal Bioscience
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• v.35 no.1
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• pp.147-152
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• 2022

Objective: This study was conducted to obtain an objective index that can be quantified and used for establishing an animal welfare certification standard in Korea. For this purpose rumen pH, ruminating time, milk yield, milk quality, and blood components of cows reared in farms feeding high forage level (90%) and farms feeding low forage level (40%) were compared. Methods: Data on rumen pH, rumination time, milk yield, milk fat ratio, milk protein ratio, and blood metabolism were collected from 12 heads from a welfare farm (forage rate 88.5%) and 13 heads from a conventional farm (forage rate 34.5%) for three days in October 2019. Results: The rumination time was longer in cattle on the welfare farm than on the conventional farm (p<0.01), but ruminal pH fluctuation was greater in the cattle on conventional farm than the welfare farm (p<0.01). Conventional farms with a high ratio of concentrated feed were higher in average daily milk yield than welfare farms, but milk fat and milk production efficiency (milk fat and milk protein corrected milk/total digestible nutrients) was higher in cattle on welfare farms. Blood test results showed a normal range for both farm types, but concentrations of total cholesterol and non-esterified fatty acid were significantly higher in cows from conventional farms with a high milk yield (p<0.01). Conclusion: The results of this study confirmed that cows on the animal welfare farm with a high percentage of grass feed had higher milk production efficiency with healthier rumen pH and blood metabolism parameters compared to those on the conventional farm.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.3
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• pp.146-154
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• 2022

This experiment was conducted to evaluate the growth characteristics and productivity of silage corn varieties developed in Korea. Corn cultivation was carried out using the experimental field in the Pyeongchang campus of Seoul National University (550 m above sea level). There have 10 domestic cultivars (Gwangpyeongok, Dacheongok, Yanganok, Jangdaok, Cheongdaok, Daanok, Sinhwangok, Sinhwangok II, Pyeonggangok, and Hwangdaok) with one imported cultivar (P1543) which tested as a control, and randomized block design with three replications. Among the 100-grains weight of the seeds, Dacheongok was the heaviest, and the germination rate for each variety was 74.6% on average, while that of Daanok and Sinhwangok were over 90%. Sinhwangok was the fastest in tasseling and silking date. The number of days required to be silking date was as slow as 85 days in Dacheongok, Cheongdaok and Pyeonggangok, and as fast as 80 days or less in Sinhwangok, Sinhwangok II and Hwangdaok. The plant height of P1543 was the highest as 344cm, and Hwangdaok and Daanok were short. In terms of the ratio of ears, Daanok had the highest rate of 60.18%, and Jangdaok and Dacheongok had the lowest. There was no significant difference in dry matter content in stover, but P1543 was generally higher in ear and total dry matter content. The dry matter yield was highest in P1543, and the yield of TDN was significantly higher in P1543 and Yanganok. There was a significant difference in the crude protein content of ears and the dry digestibility of stems (p<0.05), while there was no significant difference in the content of each part or element. Combining the above results, Yanganok was the highest in terms of yield, and Dacheongok, Sinhwangok and Pyeonggangok were also recommended for domestically grown corn varieties in the mountainous regions of Gangwon-do.

• Journal of the Korean Institute of Gas
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• v.3 no.1
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• pp.33-40
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• 1999

The extraction characteristics of lipids from powdered sea mustard have been investigated by the use of supercritical carbon dioxide($SC-CO_2$) and cosolvents. The extraction rate was increased as the particle size of the sea mustard is smaller, the pressure is higher, the temperature is lower, and the quantities of the fluid is more. However, the extraction yield of lipids from sea mustard was almost constant at a given condition. The optimum extraction condition was determined with the extraction yield of $1.45wt\%$ at 300um of particle size, 313K of $SC-CO_2$ temperature, 13.8MPa of pressure, and 30L/min of flow rate. Ethanol was the most efficient cosolvent among ethanol, methanol, and hexane. The extraction yield was increased at about 2.21times by the addition of ethanol as a cosolvent to $SC-CO_2$. As the residence time and the average concentration of lipids were decreased, the mass transfer parameter($k_fa$) was increased. But the opposite result was obtained when the ethanol was used as cosolvent.

• Korean Journal of Medicinal Crop Science
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• v.25 no.6
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• pp.397-403
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• 2017

Background: This study was aimed at evaluating the growth, yield, and carbohydrate content in the whole Allium hookeri plant with shading treatment in hot summer. Methods and Results: Different shading rate, including 0 (control), 35 or 55%, was employed from the June $21^{st}$ to August $31^{st}$. Daily average air and soil temperature, which were approximately $2.5^{\circ}C$ and $3.8^{\circ}C$ lower, respectively, were observed with both 35% and 55% treatments in July and August, with no significant difference in daily maximum air temperature. Dry weights were high, approximately 40% and 48% for the shoot and 20% and 12% for the root, with the 35% and 55% treatments, respectively, 8 weeks after shading. Division number was increased by 13% and 19.8% with the 35% and 55% treatments, respectively. The mortality rates of 150 plants were 9.1%, 4.0%, and 1.3% with the 0 (control), 35% and 55% treatments, respectively. At 4 weeks after shading, the highest and lowest sucrose levels in both shoot and root were observed with the 35% and 55% treatments, respectively. At 8 weeks after shading, there was no significant difference in the sucrose content in the shoot among the treatments. Conclusions: The highest plant growth rate and yield with the 55% treatment may be related with the decrease in both air and soil temperatures, resulting in reducted leaf respiration and thus compensate net photosynthesis.

• The Journal of Engineering Geology
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• v.20 no.1
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• pp.61-70
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• 2010

In case of groundwater recharge estimation using water table fluctuation method, specific yield affects the accuracy and confidence level of recharge rate. Nevertheless, there have been few studies on the method for the accurate estimation of specific yield in Korea. Specific yield estimated from the relationship between rainfall and groundwater levels is reasonable compared to the other methods. However, lots of factors such as artificial pumping, evapotranspiration by the plants, and a sudden increase in water levels by a heavy rainfall can affect the pattern of groundwater levels' fluctuation and make an over-estimated or under-estimated specific yield. This study obtained a reasonable specific yield by using a daily or 12 hourly average of rainfall and groundwater levels measured in a dry season.

• 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.