• Journal of Korean Society of Forest Science
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• v.90 no.3
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• pp.380-387
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• 2001

The characteristics of ecological niche, breadth and overlap, for seventeen major tree species were evaluated in the natural deciduous forest in Mt. Chumbong area. Employed by the plot sampling method, the environmental gradient for vertical niche was based on the intensity of light within the forest, and that for horizontal niche was based on multi-dimensional resources in distribution pattern. The result showed that Fraxinus rhynchophylla had the highest value of vertical niche breadth and Maackia amurensis had the lowest, and Acer pseudo-sieboldianum had the highest value of horizontal niche breadth and Betula costata had the lowest. There was no significant correlation between both measures of niche breadth. However, the tolerance index for each species was positively correlated to the values of niche breadth. Spearman's rank correlation coefficients were applied to test the correlationship between the species ranks of tolerance index and those of two ecological niche breadths. The coefficient of $r_s=0.432$ ($P{\leq}0.1$) was not enough to support significant correlationship between the tolerance index and vertical niche breadth at the 95% probability. If Carpinus cordata, rarely reach canopy of the forest due to its own growth form, are excluded from the analysis, coefficient was calculated as $r_s=0.650$ ($P{\leq}0.01$), resulting in highly significant correlationship. The Spearman's rank correlation coefficient was $r_s=0.797$ ($P{\leq}0.01$) for tolerance indices and the values of horizontal niche breadth, indicating highly significant. Four distinctive species groups, produced by cluster analysis on the basis of ecological niche overlap for each pair of species, were in considerable accord with the positively associated species constellation pattern created by the inter-species association analysis.

• Journal of Korean Society of Forest Science
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• v.95 no.1
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• pp.82-90
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• 2006

To examine the effects of nitrogen and phosphorus fertilization on soil nitrogen (N) mineralization, we monitored rates of soil nitrogen mineralization and nitrification in 41-year-old pitch pine (Pinus rigida Mill.) and Japanese larch (Larix kaempferi Gordon) stands growing on similar soil condition in central Korea. For this study, we used the buried-bag incubation method. Fertilizers were applied at three levels [control (C), 200 N kg/ha+25 P kg/ha (LNP), and 400 N kg/ha+50 P kg/ha(HNP)] on 5 June, 1996. Mineral soils (0~20 cm) were incubated 6 times with 45-day-interval from 5 June 1996 to 4 June 1997. Initial soil moisture contents were significantly different among sampling dates and between tree species. Initial soil moisture contents were 32% for C, 28% for LNP, and 26% for HNP at the P. rigida stand, and 31% for C, 31% for LNP, and 33% for HNP at the L. kaempferi stand, respectively. Mean daily N mineralization rates were significantly different among sampling dates and treatments. Annual net N mineralization and nitrification were also significantly different between the two tree species. The annual net N mineralization was 10.6 kg/ha/year for C, 23.3 kg/ha/year for LNP and 6.6 kg/ha/year for HNP at the P. rigida stand, and 2.0 kg/ha/year for C, 12.1 kg/ha/year for LNP and 16.7 kg/ha/year for HNP at the L. kaempferi stand. The annual nitrification was 2.8 kg/ha/year for C, 7.6 kg/ha/year for LNP and 4.3 kg/ha/year for HNP at the P. rigida stand, and 4.3 kg/ha/year for C, 14.8 kg/ha/year for LNP and 6.6 kg/ha/year for HNP at the L. kaempferi stand. The ratios of annual net nitrification to annual net N mineralization were 26% for C, 33% for LNP, 65% for HNP at the P. rigida stand, and 100% for C, 100% for LNP, 40% for HNP at the L. kaempferi stand, respectively. This study indicates that N mineralization in forest may be different by the predominant tree species and fertilization even under similar environments. It is likely that the quality of organic matter might control nitrogen mineralization and nitrification in soils.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.2
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• pp.87-98
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• 2016

During the period between July 3 and 27 of 2009, water samples were collected from the Russian coast at a depth of 30m from 26 stations (including Ulleung and Japan basins) onboard the Russian survey vessel R/V Lavrentyev following 4 lines (D, R, E, and A). The samples were analyzed for nutrients and chlorophyll a contents. All parameters exhibited higher values in warm waters than in cold waters ($NH_4:1.8-fold$, $PO_4:1.8-fold$, $SiO_2:1.2-fold$, and chlorophyll-${\alpha}$:1.9-fold), except nitrates, which was 1.4-fold higher in cold waters than in warm waters. The horizontal distribution of ammonia, phosphate, and chlorophyll-${\alpha}$ was very similar to each other and showed the highest values in the waters near Russia, where a upwelling influence of cold current and bottom water prevails, while relatively low distribution was observed at the Ulleung Basin. On the other hand, nitrates showed the highest concentration at the Ulleung Basin, which is under the direct influence of the Tsushima warm water, and showed a gradual decrease northward. The N/P ratio showed the highest value in the Tsushima middle water, rather than in the North Korean Cold Water, the Tsushima Warm Water was the primary source of nitrate flow into the East Sea. However, the average concentration of phosphate in the warm waters was < $0.2{\mu}M$, thereby limiting phytoplankton growth, while a high concentration of phosphate in cold waters showed a direct correlation with chlorophyll-${\alpha}$. The results of principal component analysis for the identification of primary factors that influence the marine environment showed that principal component I was water temperature and principal component II was influenced chlorophyll-${\alpha}$ and nutrients. Therefore, Study area has greatest influenced by water temperature, and clearly distinct cold and warm water regions were observed in the East Sea.

• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.2
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• pp.64-73
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• 2015

The distributions of Pb and Cd concentrations in the surface seawater of the East Sea were investigated during the R/V Lavrentyev cruise (July 2009) in which four transects from Russia shore to South were conducted to collect 26 surface water samples. The total dissolved concentrations of Pb and Cd were measured using ICP-MS (Perkin Elmer, DRC-e). In the coastal area, their concentrations of Russia shore (Pb, 0.08; Cd, 0.10 nM) were comparable for Cd but on the other hand, 6 times lower for Pb than Korea shore (Pb, 0.49; Cd, 0.11 nM). In the subregion, their concentrations of Warm region (Pb, 0.22; Cd, 0.01 nM) were about 1.7 times higher for Pb but 0.4 lower for Cd than Cold region (Pb, 0.13; Cd, 0.14 nM). The distributions of Pb and Cd concentrations were divided by lowest level at $10^{\circ}C$ of water temperature. Below $10^{\circ}C$, Pb and Cd concentrations increased when surface water temperatures decreased. Above $10^{\circ}C$, their concentrations increased with temperature, which showed highest concentrations in the Ulleung basin, directly influenced by flux from East Korean Warm Current and neighboring countrys (Korea and Japan). Specially, in the case of Pb, the concentrations decrease remarkablely with temperatures decrease from D10 directly influenced by flux from East Korean Warm Current, which shows highest Pb level. By comparing with other sea areas (Western Mediterranean, East Pacific), Pb concentrations in the East Sea were a little higher. The influence of East Korean Warm Current and neighboring countrys (Korea and Japan) may be relatively important. Therefore, the distribution of Cd may primarily be influenced by mixing of different water masses while the distribution of Pb may mainly be influenced by flux from East Korean Warm Current and atmospheric inputs. River inputs and interaction with particulate materials may also some roles for the distribution of these elements.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.2
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• pp.60-67
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• 2002

To determine whether nitrogen (N) uptake by phytoplankton below the euphotic zone in the Yellow Sea is considerable, we measured the uptake rates of nitrate and ammonium using $^{15}N$-labeled stable isotope $K^{15}NO_{3}$ and $^{15}NH_{4}Cl$, in May and November 1997 at total 10 stations. Depth-integrated uptake rates of nitrate and ammonium over the euphotic zone during this study ranged from 1.8 to 15.3 mg N $m^{-2}$ $d^{-1}$ and from 5.0 to 132.2 mg N $m^{-2}$ $d^{-1}$, respectively, and ammonium uptake predominated at 9 of 10 stations (1.9-19.4 fold). Depth-integrated uptake rates of nitrate and ammonium over the whole water column ranged from 2.9 to 22.0 mg N $m^{-2}$ $d^{-1}$ and from 15.7 to 175.5 mg N $m^{-2}$ $d^{-1}$, respectively. The significant proportion of whole water column N uptake was attributed to uptake by phytoplankton below the euphotic zone, ranging from 13.0 to 86.2% for nitrate and from 13.8 to 67.8% for ammonium, indicating that phytoplankton N uptake below the euphotic zone is at times considerable in the study area. The results suggest that when phytoplankton below the euphotic zone in the Yellow Sea are again entrained into the euphotic zone by a certain physical forcing such as turbulent mixing and the vertical movement of thermocline, these episodic events may significantly affect the material fluxes within the euphotic zone. Furthermore, the results suggest that a portion of regenerated production estimated from $^{15}N$-ammonium uptake should be included in new production estimates, which otherwise could be underestimated in the Yellow Sea.

• Journal of Preventive Medicine and Public Health
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• v.24 no.4 s.36
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• pp.531-548
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• 1991

To assess the adequacy of medical manpower and medical fee for the newborn nursery care, the author visited 20 out of 24 hospitals with the pediatric training program in Youngnam area between July 29 and August 14, 1991. Total number of newborn, both normal and sick, admission and discharge in 1-30 June 1991 was obtained from the logbook of nursery. Head nurse and staff pediatrician of the nursery were interviewed to get the current staffing for the nursery and their subjective opinion on the adequacy of nursery manpower and the difficulties in recruiting manpower. Average medical fee charged for the maternity and normal newborn nursery care was obtained from the division of self-audit of medical insurance claim of each hospital. Average minimum requirement of nursing care time for one normal newborn per day was 179.5 (${\pm}58.6$) minutes; 202.3(${\pm}50.7$) minutes for the university hospitals and 164.2(${\pm}60.5$) minutes for the general hospitals. The ratio of minimum requirement of nursing care time and available nursing time was 1.42 on the average. Taking the additional requirement of nursing care for the sick newborns into consideration, the ratio was 2.06. The numbers of R. N. and A. N. in the nurserys of study hospitals were 31%, and 17%, respectively, of the nursing manpower for the nursery recommended by the American Academy of Pediatrics. These findings indicate that the nursing manpower in newborn nursery is in severe shortage. Ninety percent of the head nurses and 85% of the staff pediatrician stated that the newborn nursery is short of R.N. and 75% of them said that the nurse's aide is also short. Major reason for not recruiting R.N. was the financial constraint of hospital. For the recruitment of nurse's aide, short supply was the second most important reason next to the financial constraint. However, limit of quarter in T.O. was the mar reason for the national university hospitals. Average total medical fee for the maternity and newborn nursery cares of a normal vaginal delivery who stayed two nights and three days at hospital was 219,430won. Out of the total medical fee, 20,323won(9.3%) was for the newborn nursery care. In case of C-section delivery who stayed six nights and seven days, total medical fee was 732,578won and out of the total fee 76,937won (12.0%) was for the newborn care. Cost for a newborn care per day by cost accounting was 16,141won for the tertiary care hospitals and 14,576won for the all other hopitals. The ratio of cost and the fee schedule of the medical insurance for a newborn care per day was 5.0 for the tertiary care hospitals and 4.9 for the all other hospitals. Considering the current wage level of the medical personnel, capital investment for the hospital facilities and equipments, and the cost for hospital maintenance, it is hard to expect adequate quality care in the newborn nursery under the current medical insurance fee schedule.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.4
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• pp.313-322
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• 2007

The object of this experiment was to investigate the food habits of dairy goats fed with various roughage sources. The experimental trials were conducted at Chungnam National University in 2007. The experimental roughages include five sources and 25 species in all; grass sources: 5 species (Lolium perenne, Festuca arundinacea, Poa pratensis, Agrostis alba and mixed grass, legume sources: 5 species (Trifolium pratense, Medicago sativa, Trifolium repens, Melilotus officinalis and Vicia villosa), browse sources : 5 species (Quercus serrata Thunb., Prunus jamasakura Sieb., Quercus aliena Blume, Robinia pseudoaccacia and Pinus densiflora), weed sources: 5 species (Artemisia princeps Pampanini, Erigeron canadensis, Alopecurus aegualis Sobolewski, Echinochloa crusgalli var. frumentacea (Roxb.) Wight and Rumex crispus), and native grass sources: 5 species (Zoysia japonica Steudel, Agropyron tsukushiense var. transiens (Hack) Ohwi., Arundinella hirta (Thunb.) Tanaka, Miscanthus sinensis Anderss and Phragmites comunis Trin). Ten dairy goats(Saanen) were selected which had nearly the same body weight(average 31kg). Experimental roughages were prepared by 0.5kg per 1 species fed to dairy goats, and the experiment was carried out from 09:00 to 18:00. The chemical composition and dry matter digestibility of each roughage source and species were significantly different at the sampling area, plant species, growth stages and cutting period. The dairy goats ate more roughages which had low fibrous contents, but high dry matter digestibility. Among all the 25 species of roughages, the favorite intake species order by dairy goat was observed like this: perennial ryegrass, tall fescue and red clover, respectively, and the lower intake species order was Rumex crispus. On the other hand, compared to each roughage source, total intake amount by dairy goats was showed as forage grasses (59.0%) which contained grasses(33.3%) and legumes (25.7%), browse (19.6%), weeds (15.9%) and native grasses (5.5%). Based on the result, the food intake type of dairy goats seems to be closer to grazer type.

• Korean Journal of Environmental Agriculture
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• v.39 no.1
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• pp.1-9
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• 2020

BACKGROUND: The aim of this study was to investigate the soil chemical properties and soil bacterial community of the cropping system for Cnidium officinale Makino. METHODS AND RESULTS: The bacterial community was analyzed for the relative abundance and principal coordinated analysis (PCoA analysis) by using by Illumina Miseq sequencing. The correlation analysis between soil chemical properties and soil bacterial community were analyzed by Spearman's rank correlation and DISTLM analysis. Soil bacterial community (phylum and class) showed two distinct clusters consisting of cluster 1 (first cropping) and cluster 2 (continuous cropping) from 2 different cultivation methods of Cnidium officinale Makino. PCoA and DISTLM analyses showed that soil pH and Ca significantly affected soil bacterial community in cultivation area of Cnidium officinale Makino. In addition, Spearman's rank correlation showed significant correlation between relative abundance (Acidobacteria and Actinobacteria) and soil factors (soil pH and Ca). CONCLUSION: The results of this study were considered to be important for determining the correlation between soil properties and soil bacterial community of the cropping method for Cnidium officinale Makino. Furthermore, the results will be helpful to investigate the cause of continuous cropping injury of the Cnidium officinale Makino by examining the changes of soil properties and soil bacterial communities.

• Research in Plant Disease
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• v.16 no.2
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• pp.115-120
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• 2010

In this study, changes in virus disease occurrence and yield were monitored in conventional cropping system(rice-barley) and soybean-barley double cropping system in virus-prone area for 5 years. Also, changes in the density of Polymyxa graminis, a fungal vector, was investigated. In assay tests, mixed infection of Barley yellow mosaic virus (BaYMV) and Barley mild mosaic virus (BaMMV) was observed. Disease severity was in the range of 7~9 in conventional cropping system. In continuous cropping of soybean-barley and 3-yearfallow land, disease severity also was around 7. However, disease severity was reduced to medium level (5) when barley cultivation was paused for one or two years in soybean-barley cropping. When barley cultivation was paused for a year, the density of P. graminis, a fungal vector for BaYMV and BaMMV, reduced in barley root and soil. Similarly, barley growth was also enhanced by adopting fallow seasons. Compared with the fifth year of conventional cropping, the number of tillers per $m^2$ was increased by 158 when barley cultivation was paused for an year in soybean-barley cropping. When soybean and barley were cultivated continuously or complete fallow period was extended to three years, plant height and the number of tillers of barley were decreased. Yield components of barley in soybean-barley cropping were superior to those in rice-barley cropping. Compared with the fifth year of conventional cropping and soybean-barley cropping, culm length of barley was 1.3~2.3 cm higher and the number of tillers per $m^2$ was 36~90 higher when barley cultivation was paused for one or two years. However, those in continuous cropping of soybean-barley and 3-year-fallow land were lower compared with conventional cropping. Similarly, yield was increased when barley cultivation was paused for one or two years in the third, forth, and fifth years when compared with conventional cropping.

• Journal of the Mineralogical Society of Korea
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• v.25 no.3
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• pp.163-173
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• 2012

In this study, we determined the relative clay mineral composition of 51 surface sediments from SEYSM (Southeastern Yellow Sea Mud) (northern part 25, southern part 26) and 30 river sediments inflow to Yellow Sea using the semi-quantitative X-ray diffraction analyses. In addition to we analyzed illite characteristics of the same samples. The clay-mineral assemblage is composed of illite (61~75%), chlorite (14~24%), kaolinite (9~14%), and smectite (1~7%), in decreasing order. The average composition of each clay mineral is not different from northern part to southern part of SEYSM except a little higher kaolinite and lower smectite content in northern part. Smectite content generally has reverse relationship with illite content. Mineralogical characteristics of illite such as illite crystallinity index also is not different between two areas and show very narrow range (0.18~0.24 ${\Delta}^{\circ}2{\theta}$). Our results reveal that clay mineral composition and illite characteristics are nearly the same between northern and southern part of SEYSM. Characteristics of surface sediments in SEYSM is closer to Korean river sediments than Chinese Hanghe sediments, however it is necessary to investigate further study including Yangtze river sediments. This study conclude that most of surface sediments in SEYSM attribute to the supply of considerable amount of sediments from the nearby Korean rivers. The large sediment budget and high accumulation rate in the SEYSM can be explained by erosion and reworking of surface sediments in this area. Tidal and regional current system around SEYSM might contribute these erosional and depositional regimes.