• Korean Journal of Medicinal Crop Science
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• v.7 no.4
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• pp.282-287
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• 1999

This study was conducted to investigate the effects of different soil texture in agronomic characteristics, root yield and quality of baloon flower (Platycodon grandiflorum A. DC.). Three kinds of soil texture, sandy loam, silt loam and clay loam, were tested for two years. Baloon flowers were seeded with 20cm row space and cultivated in the one square meter pot with 0. 6m depth. Fifty plants per pot were remained. In growth characteristics of one-year-old plants, shooting date was not significantly different according to the changes of soil texture. The ratio of stem growth was highest between July and August. In two-years-old plants, it was showed between May and June. Plants grown on clay loam showed the highest growing characteristics than those of other soil textures. Dry root weight cultivated on clay loam was 274kg/10a in one-year-old and 934kg/10a in two-years-old plants. The content of ethanol extracts from root was highest at those of sandy loam as 47.1 % in one-year-old root. The crude saponin content was not different significantly among the three kinds of soil texture.

• Journal of Conservation Science
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• v.29 no.3
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• pp.209-221
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• 2013

This study is to interpret the construction characteristics and the provenance of soil layers from the Dongnamri site in Baekje Kingdom of Buyeo, Korea. The soil layers is divided into present age layer, Baekje layer and lower part layer, and the soils formed in the Baekje Kingdom period is divided into the Baekje 1st layer and the Baekje 2nd layer according to temporal intervals. The soil layers gradually becomes darker in color and higher in mineral content towards the lower part layer. However, the particular distinction between layers of the soils could not be identified. Additionally, the soil layers show a similar characteristics of mineralogy and geochemical evolution regardless of the layers. This indicates that the sites were made with weathered soil from an identical bed rock, and the site show a similarity to the surrounding soil, indicating its possibility of being the original materials. However, through the analysis of particle size, the first and second Baekje layers occurred that these layers were formed by setting up the soil with high content of sand on the bottom and stacking the soil with high content of silt on top of it.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.4
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• pp.81-95
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• 2012

This study was intended for Fagus engleriana stand in Is. Ulleung where the disturbance of vegetation has been caused by the exploitation and the increase of tourists. For the effective conservation and management on this issue, this study was conducted provide basic data. The sixteen study sites ($20{\times}20m$) were installed in the dominant Fagus engleriana stand and the base environment and vegetation were investigated. The Fagus engleriana stand was classified into two groups, The Fagus engleriana stand was classified into two groups, community A is Fagus engleriana-Sorbus amurensis and community B is Fagus engleriana-Acer pictum subsp. Mono by cluster analysis and community A were nothing signigicant by indicator species analysis. Community B were Eight species (Tsuga sieboldii, Camellia japonica, Dystaenia takesimana ect.) significant by indicator species analysis. The diameter class of 16cm to 25cm was 53.7% in population structure of Fagus engleriana, which was the highest and showed inverse J-distribution. Species diversity index (H') of investigated woody layer group ranged from 0.99 to 2.05 and that of under layer group ranged from 1.75~2.59. According to Non-metric Multidimensional Scaling (NMS) analysis, the woody layer was divided into community A developed in the region having relatively high sand content at high altitudes and community B formed at the place having relatively high clay content at low altitudes. Then this classification was significant through Multi-Response Permutation Procedures (MRPP) analysis. The distribution of understory vegetation through Detrended Correspondence Analysis (DCA) was induced by the silt content and cover degree of vegetation layer.

• Korean journal of applied entomology
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• v.58 no.1
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• pp.37-47
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• 2019

A survey on the geographical distribution of two soybean cyst nematodes, Heterodera glycines and Heterodera sojae, was conducted in soybean cultivation areas in the Gangwon-do and Chungcheongbuk-do provinces. In 67 fields of 10 counties or cities in Gangwon-do province, H. glycines was detected in 13 fields, H. sojae was detected in five fields, and both species were found in two fields. In 84 fields of nine counties or cities in Chungcheongbuk-do province, H. glycines was detected in 27 fields, H. sojae was detected in four fields, and both species were found in five fields. The diversity and dominance of the plant parasitic nematodes in the Gangwon and Chungbuk provinces were not significantly different among the soybean cultivars. The diversity and dominance index of the plant parasitic nematodes according to the presence or absence of soybean cyst nematodes did not show any significant difference between the soybean cultivation areas of both provinces. The relationship between the soybean cyst nematodes and soil chemical properties showed a low coefficient of determination, and the density of soybean cyst nematodes tended to increase as the pH and available phosphate content in soil samples increased. The soil texture of cyst nematode-detected fields was mostly sandy soils, which amounted to about 60% of the total. As the clay and silt content increased, the density of soybean cyst nematodes tended to decrease, and as the sand content increased, the density of cyst nematodes tended to increase.

• Economic and Environmental Geology
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• v.16 no.2
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• pp.65-78
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• 1983

This report deals with the sedimentological study of the littoral sand of beaches in the Busan area. The purpose of this report is to know the grain size, mineralogical composition, heavy mineral and clay mineral of the beach sands, and gravity measurements of the Nagdong River Deltas. 1) As a whole, the littoral sand of the beaches are composed of uniformly medium grained, moderately sorted and nearly symmetrical. The barrier sand of the Nagdong Estuary is composed of fine grained, well sorted and nearly symmetrical. 2) The littoral sand of the beaches is transported by saltation and rolling. The barrier sand of the Nagdong Estuary is transported by suspension and saltation. 3) In the littoral sand of the beaches, the ratio of feldspar to quartz is 1 :2.31 and in the barrier sand of the Nagdong Estuary 1:1.40. 4) The content of heavy mineral of samples ranges from 0.54 to 3.87 %. The principal heavy minerals are hornblende, pyroxene, epidote, garnet, leucoxene, zircon, apatite, magnetite, hematite and ilmenite with minor accessories of rutile and olivine. 5) The x-ray diffraction analysis of the clay mineral informs the existence of quartz, feldspar, kaolinite and montmorillonite. The montmorillonite is considered to have been derived from the alteration of acidic volcanic rocks. 6) To determine the depositional structure of the Nagdong Estuary, Gravity measurements were made. Free air anomaly ranges from 14.5 mgal to 33.5 mgal and Bouguer anomaly ranges from 14.3 to 23.5 mgal and both are closely related to the topography. According to the interpreted layer structure, the upper layer composing sand, silt and clay, the intermediate layer composing sand with gravel, the lower layer composing weathered and soft rock, and bed rock composing hornfels or andesite. 7) The depositional environments of the study, the littoral area is dominated by the marine environment and the Nagdong Estuary by the mixed environment.

• Ocean and Polar Research
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• v.39 no.1
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• pp.23-34
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• 2017

This study was carried out to investigate the spatial distributions of the macrobenthic communities in the Seomjin River estuary from May, 2015 to May, 2016. The number of species was 163, the mean density was $1,865ind.m^{-2}$, biomass was $204g{\cdot}wet\;m^{-2}$ during this study period. The highest number of species and density appeared among polychaetes whereas the most biomass was contributed by mollusks due to the presence of Corbicula japonica in every season. The study area was divided into 3 regions with similar benthic fauna responding to the gradient of the salinity. Praxillella praetermissa was the dominant species in regions of over 30 psu during all seasons. C. japonica and Hediste diadroma were dominant in the upper regions of the Seomjin River where the salinity was less than 10 psu. Heteromastus filiformis showed the broadest distributional range and dominated in all seasons except for the most upper stream at st. 7. From the result of the Bio-Env analysis, salinity was the most important environmental factor affecting the formation of macrobenthic communities in the study area, and salinity and TOC were the highest contributors to the macrobenthic communities. From the correlation analysis between major dominant species and environmental factors, C. japonica, Prionospio japonica and H. diadroma showed a negative correlation with salinity, while P. praetermissa and Scolectoma longifolia showed a positive correlation. H. filiformis was little affected by salinity but showed a positive correlation with TOC or silt content of sediment.

• Ocean and Polar Research
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• v.26 no.1
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• pp.23-32
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• 2004

As a baseline survey for long-term monitoring on environmental change around the Antarctic King Sejong Station, distribution pattern of Deschampsia antarctica Desv., a flowering plant newly colonized were investigated qualitatively and quantitatively in both austral summer 2002 and 2003. Dispersal of the seeds and vegetative leaves by skuas might lead to the colonization into this area from neighbors in Maxwell Bay. The pioneer populations were observed around ponds and a stream of the Sejong Point in January 2002, and the maximum dispersal area was four times expanded after a year. Most of the populations were formed on the stable and well-drained substrate, which consisted of moss carpet of Sanionia georgico-uncinata (65%) and pebbles (25%), while only a few young individuals were observed on the unstable and watertight silt-sandy area. Especially, S. georgico-uncinata was being effectively utilized as their primary substrate with the soft, coarse and water-contained leaves. Also the perennial mature plants of D. antarctica were mainly formed on the moss carpet rather than pebbles. A few individuals were grown on other mosses of Polytrichastrum alpinum, Bryum pseudotriquetrum, Pohlia cruda, and Conostomum magellanicum and on a liverwort of Cephaloziella varians. We expect that dispersal of D. antarctica and the following succession to grass field will be countinuously and dynamically proceeded in this area, with the characteristics of ecological niche against the initial moss populations, on the similar continuity of environmental conditions. The continuous observations are needed with establishment of database on environmental change of micro-habitats, e.g. the water content and nutrients of soil and the underground temperature and permafrost.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.9-16
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• 2010

The purpose of this study is to clarify the origin of organic matters on sediment and the characteristics of seasonal variation at an estuarine tidal flat. Silt-clay content (<63 ${\mu}m$), chlorophyll a, TOC, C/N ratio and the stable isotope ratio of carbon and nitrogen were measured at tidal flat around the estuary of the Nanakita River. As a result, organic matters originating from marine organic matter and bethic microalgae greatly contributed to sedimentation of organic matters at Stn.A, sandy tidal flat, though terrigenous organic matters did at Stn.C, muddy tidal flat. Furthermore, it was revealed that the volume and origin of organic matters in the sediments depended on seasonal variation, and the factors were different from the Stns, i.e. bentic microalgae and event for Stn.A, and the eventual sedimentation of organic matters originating from terrestrial plants, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.2
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• pp.145-154
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• 1990

Amounts of total suspended matter(TSM) around the Kori waters have been monitored for two years to understand the dispersal pattern of fine-grained sediment. Average concentration of the TSM is $3\~4\;mg/\iota$ in the surface and $3.5\~5\;mg/\iota$ in the near-bottom water. Semi-quantitative analysis for the four major clay minerals in TSM is also performed. The average relative abundance of each clay mineral such as illite, kaolinite, chlorite, and smectite is $65\%,\;17\%,\;17\%$, and $1\%$, respectively. It seems that the majority of recent fine-grained sediment deposited around the Kori area is derived from the Nakdong River. The texture of surface sediment is also dominated by fine-grained fraction leading up to $90\%$ of silt and clay content. The grain size decreases seaward progressively.

• Journal of Korean Society on Water Environment
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• v.31 no.3
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• pp.304-312
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• 2015

In this study, we tried to determine the vertical variation of sediment structure and geochemical characteristics, core sediment was collected in the Nakdong River midstream on August, 2014. Core sediment mainly composed of sand (51.48%) and silt (46.21%) and coarsing upward changed from sM to mS facies. IL and TOC were decreased from lower to upper layer. C/N ratio was lower than 10 so the organic matters were originated from underwater creatures and C/S ratio was decreased from lower to upper layer. Heavy metal (Al, Fe, Zn, Cr, Pb, Ni, Cu, Cd) content were decreased from lower to upper layer and seriously polluted condition is not. These results are thought to be due to the effect of natural and anthropogenic in the fluctuation of flow.