• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2003.04a
• /
• pp.438-441
• /
• 2003

남해 동부 연안 지역 지하수의 해수 침투 영향을 광역적으로 파악하기 위하여, 202개소의 지하수 시료를 채취하고 수리지구화학적 연구를 수행하였다. 전체 시료 중 14.4%가 500 $\mu\textrm{m}$/cm을 초과하는 높은 EC값을 나타내어 해수 영향을 시사해 주었다. 해수 영향 판단의 또 다른 파라메터로 사용되는 CI/HCO$_3$ 몰비는 전체 시료의 23.3%가 1.3 이상의 값을 나타내었다. 한편, 대표적으로 해수침투 영향 및 인위적 오염의 영향을 각각 반영하는 것으로 알려진 Cl과 NO$_3$의 농도에 관한 누적도수분포도를 작성하여 배경수질군과 오염영향군을 구분짓는 배경치(background concentration)를 구한 결과, 각각 Cl = 22.3 mg/1 및 NO$_3$= 23.1 mg/l로 나타났다. 이 두 파라메터의 농도 분포를 기준으로 하여 채취된 지하수 시료를 크게 4개의 그룹으로 나눌 수 있었다. 그 결과, 자연적 또는 인위적 기원의 오염이 배제된 그룹 1은 전체 시료의 31%, 자연적 오염(해수 영향)을 반영하는 그룹 2는 전체의 24%, 인위적 오염의 영향을 반영하는 그룹 3은 전체의 9%, 해수 영향 및 인위적 오염을 동시에 반영하는 그룹4는 전체의 36%로 나타났다. 또한 그룹2와 그룹4는 대부분 Na-Cl유형으로 진화하는 Ca-Cl유형을 나타내었다. 따라서, 여러 지구화학 방법에 의한 해수 영향 판단 결과는 서로 잘 일치하고 있음을 알 수 있다. 결국, 지구화학적 파라메터를 종합적으로 활용함으로써, 연안 지역 해수침투의 효과적인 파악은 물론 예측 및 방지, 복구에 효과적으로 사용될 수 있을 것으로 판단된다.으로 토양에서 유동 가능성이 있는 중금속만을 추출하였다. 분석실험은 토양의 Cd2+ 와 Pb2+를 대상으로 행하여졌으며, 여러 토양에서 추출 분석한 결과를 EDTA분석결과와 비교하였다. 실험결과, 중금속은 매우 신속하게 고분자 자성체와 결합하였고, 그 후 자성체를 외부 자장으로 모은 후 산으로 용해시키고, 결합된 중금속은 Graphite furnace AAS로 분석함으로써 빠르고 효율적으로 분석실험을 수행할 수 있음을 알 수 있었다. 한편, 실험에서 나타난 수치들을 비교 검토한 결과 토양 분석시 sandy soil에서는 자성체를 이용한 분석이 EDTA에 의한 방법보다 더 높은 추출도를 보인 반면, silt 함량이 많은 토양의 경우에서 EDTA분석에서 더 높은 중금속 추출도를 보였다.s 중에서 490nm와 555nm의 복합밴드를 포함하는 OC2 알고리즘(ocean color chlorophyll 2 algorithm)을 사용하는 것이 OC2 series 및 OC4 알고리즘보다 좋은 추정 값을 도출할 수 있을 것으로 기대된다.환경에서는 5일에서 7월에 주로 이 충체의 유충이 발육되고 전파되는 것으로 추측되었다.러 가지 방법들을 적극 적용하여 금후 검토해볼 필요가 있을 것이다.잡은 전혀 삭과가 형성되지 않았다. 이 결과는 종간 교잡종을 자방친으로 하고 그 자방친의 화분친을 사용할 때만 교잡이 이루어지고 있음을 나타내고 있다. 따라서 여교잡을 통한 종간잡종 품종육성 활용방안을 금후 적극 확대 검토해야 할 것이다하였다.함을 보이고 있다.X> , ZnCl$_{3}$$^{-}$같은 이온과 MgCl$^{+}$, MgCl$_{2}$같은 이온종을 형성하기 때문인것 같다. 한편 어

• Korean Journal of Soil Science and Fertilizer
• /
• v.48 no.3
• /
• pp.194-204
• /
• 2015

Six study sites in Gumi, Goryeong in Gyeongbuk province and Naju in Jeonnam province were selected to investigate soil properties of poorly drained horizons in paddy soils. The horizons were re-established layers which were parent material layers originated from fluvial deposits. Topsoil layers were differentiated from piled parent materials while soil structure of the topsoil layer was massive with striated microstructure. Compaction at soil re-establishment and a lack of structure and aggregate development in these soils may cause the limitation of vertical water movement and result in poorly drained horizons. Soil samples were taken from paddy fields with top soils of sandy loam, silt loam and silty clay loam and re-established soils of coarse and fine texture. The samples were taken from each horizon for the analyses of soil chemical and mineral properties. Soils with re-established soils of coarse texture had greater amounts of sands from top soil texture distributions, while soils with fine texture had greater amounts of silts. Chemical properties of top soils were analyzed from rice cultivated soils at the time of re-establishments and one year after the re-establishments. The coarse texture of the re-established horizons decreased in EC values from 0.23 to $0.11(dS\;m^{-1})$, available phosphate values from 112 to $54(mg\;kg^{-1})$, and exchangeable Ca values from 6.6 to $4.9(cmol_c\;kg^{-1})$. On the other hand, soils with fine texture showed decrease only in pH and exchangeable Ca values. Especially, organic matter and available phosphate contents showed heterogeneous distributions from each horizon. This result may be caused by mixture of plough layer and subsurface layer during and consolidation. Hydraulic conductivity values were low at the boundaries of top soil and parent material layers except SL/coarse soil. Soil microstructure was massive structure without soil clods or pores and showed striated structure. Therefore, re-established paddy fields with fluvial deposits as parent material layers showed limited vertical movements of soil water because of occurrence of compacted layers and less-development of soil clods and aggregates.

• Korean Journal of Plant Resources
• /
• v.23 no.4
• /
• pp.261-273
• /
• 2010

This study intended to investigate the environmental factors including soil and vegetation in order to understand the environmental and ecological characteristics of seven different habitats of Viola websteri. These habitats, according to investigations, are mostly located on the slope of mountains facing north at an altitude of 343 m to 991 m above sea level with angle of inclination from 1 degree to 33 degrees. The type of soil is mostly sandy loam and the average field capacity of soil is 28.97%. Their average organic matter is 16.63%, soil pH 5.62, and available phosphorus is 14.75%. A total of 133 vascular plants are identified in 18 quadrates of seven habitats. Dominant species of woody plants in seven habitats are represented as Acer pictum subsp. mono and Quercus mongolica in tree layer, and Acer pictum subsp. mono in subtree layer. Importance value of Viola websteri is 9.66%, as regards the herbaceous layer, and five highly ranked species such as Meehania urticifolia(8.53%), Pseudostellaria heterophylla(6.51%), Hylomecon vernalis(5.15%), Oxalis obtriangulata (4.52%), and Pseudostellaria davidii(4.15%) are considered to be an affinity with Viola websteri in their habitats. The degree of their average species diversity is 1.32, and that of dominance and evenness are 0.08 and 0.89, respectively. Correlation coefficients analysis based on environmental factors, vegetation and soil analysis shows that the coverage of Viola websteri is correlated with silt and sand ratio, and coverage of tree layers are correlated with species richness and altitude. Cluster analysis based on vegetation structure of each habitats are forms a three groups.

• Journal of Wetlands Research
• /
• v.22 no.4
• /
• pp.295-301
• /
• 2020

This research analyzed the relationship between environmental factors and the density of Sycios angulatus in the Miho Stream, Geum River water system in order to secure basic data for the control of the ecosystem-distrubing plant Sycios angulatus. As a result of the soil particle size analysis of Sycios angulatus habitat, it was found that the density of Sycios angulatus decreased as the silty and clay contents increased. Most of the Sycios angulatus habitats had high sandy and silt content, and low clay content of less than 2%. The increased flow rate reduced the density of Sicyos angulatus. This is because when the flow rate is increased, the Sicyos angulatus cannot grow due to the change in soil characteristics. Water quality plays a role in supplying nutrients when Sicyos angulatus are submerged. However, due to the change in soil characteristics during flooding, the density of Sicyos angulatus tended to decrease due to impaired growth. The Sicyos angulatus can be managed through artificial and natural techniques. The appropriate natural control technique is the creation of a natural waterway in the habitats to change the water contents.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.37 no.1
• /
• pp.43-59
• /
• 2017

This study presents the prediction methodology of debris flow occurrence areas using the SINMAP model. Former studies used a single calibration region applying some of the soil test results to predict debris flow occurrence in SINMAP model, which couldn't subdivide the soil properties for the target areas. On the other hands, a multi-calibration region using a detailed soil map and soil strength parameters (c, ${\phi}$) for each soil series to make up for limitation of former studies is proposed. In this process, soils with soil erodibility factor (K) are classified into three types: 1) gravel and gravelly soil. 2) sand and sandy soil, and 3) silt and clay. In addition, T/R estimation method using mean elevation of target area instead of T/R method using actual occurrence time is suggested in this study. The suggested method is applied to Seobyeok-1 ri area, Bonghwa-gun where debris flow occurred. As a result of comparison between two T/R estimation method, both T/R estimations are almost equal. Therefore, the suggested methodologies in this study will contribute to set up the national-wide mitigation plan against debris flow occurrence.

• Korean Journal of Plant Resources
• /
• v.28 no.1
• /
• pp.64-78
• /
• 2015

The environmental characteristics of Astilboides tabularis were investigated to compile basic data for conservation and restoration. Natural habitats, according to investigations, were mostly located on the slopes of mountains facing north at an altitude of 432 m to 1,413 m above sea level with angles of inclination ranging from 16 degree to 49.5 degree. A total of 246 vascular plant taxa were identified from 12 quadrats in 11 habitats. The importance value of Astilboides tabularis is 20.40%, and 6 highly ranked species such as Dryopteris crassirhizoma (4.56%), Rodgersia podophylla (3.72%), Astilbe rubra (2.81%), Carex siderosticta (2.67%), Ainsliaea acerifolia (2.65%), and Meehania urticifolia (2.46%) are considered to be an affinity with Astilboides tabularis in their habitats. Average species diversity was 1.23, dominance and evenness were found to be 0.11 and 0.86, respectively. The litter depth above the soil surface was 2 to 10 cm, and soil depth was 20.8 to 67.5 cm. The soil texture of habitats were divided three types such as loam, silt loam, and sandy loam. The soil pH was 5.63 to 7.74, and the organic matter and nitrogen contents were ranged from 8.88 to 42.55%, and 1.40 to 6.58 mg/g, respectively.

• Korean Journal of Soil Science and Fertilizer
• /
• v.34 no.2
• /
• pp.98-104
• /
• 2001

Cultivation area of the plastic film-house has been continuously increased with the increase of consumers' income. Intensive land use without fallowing or crop rotation caused severe problem such as salt accumulation in soils and in turn retarded growth and low productivity. This study was carried out to solve them derived from longterm intensive farming practices. Seven farmers who are practicing plastic film-house cultivation were recommended for case study by municipal government and selected for their excellency of cultivation and soil management. The cultivation periods of these systems were in the range of 5 to 40 years in the regions mainly located in alluvial soil cultivated with cucumber, tomato and red pepper. The soils texture of the excellent farmers' fields were silt loam or sandy loam, ranged from 7 to 15 percents of clay contents. Soil bulk density, depth of plowing layer and soil aggregates contents of the farmers' soils were 0.89, 23.1 cm, 61.6% whereas those in neighboring soils were 1.10, 17.8 cm, 54.2 %, respectively. And pH, OM and $NO_3-N$ of the farmers' soils also were better than those of neighboring soils. There was no difference in population densities of nematode between the good farmers' and neighboring soils, but actinomyces and Fusarium densities of recommended farmers' soils were better than neighboring soils. The major farming practices by the good farmers were characterized by deep plowing with flooding, amendment of crude organic matter, and reduction of chemical fertilizer application before transplanting, and also drip irrigation and liquid manure application after planting. They also conducted solar sterilization with or without flooding, removal of plastic films during rainy days and culturing rice or corn as rotation crops to avoid the problems mentioned above.

• Korean Journal of Soil Science and Fertilizer
• /
• v.30 no.1
• /
• pp.72-83
• /
• 1997

Forty six natural habitats of Korean lespedeza(Leapedeza stipulacea Maxim.) were investigated for the growth characteristics, mineral contents of plant and the physico-chemical properties of natural habitat's soil compared with the upland soil nearby the habitat. The results obtained were summarized as follows. Plant height and dry matter yield were higher in the samples taken in late than early August showing large variation within the sampling date and location. Korean lespedeza showed higher contents of Fe and Mn, but lower contents of K, Ca, Mg and Cu than Alfalfa. The contents of P and Zn were about the same. The natural habitat showed higher soil pH and Ca content but lower contents of $P_2O_5$, K, and organic matter than the vicinity of natural habitats and the average soil of Korea. The contents of Mg were about the same. The soil texture of natural habitats showed much higher portion of sand and extremely low portions of silt and clay than both area. Korean lespedeza is so well adapted to the soil with low fertilizer and organic matter that other crops and most weeds fail. It also appears to thrive on the sandy loams, loamy sands of the piedmont region such as waste land and on the similar soils with variously physico-chemical properties.

• Korean Journal of Soil Science and Fertilizer
• /
• v.27 no.1
• /
• pp.3-9
• /
• 1994

Characterstics, genesis and classification of soils derived from coarse grain granitic materials were discussed with four soil series, such as Samgag, Sangju. Sachon and Yecheon which were distributed over the area of Gangdae-Ri, Nengseo-Myeon, Yeoju-Gun, Gyunggi-Do. The results are as follows. 1. Samgag, Sangju, Sachon and Yecheon had a soil of excessively, well, imperfectly and poorly drained, thus they had a soil drainage sequence. 2. Soil textural class were from sandy loam to loam. Silt and clay content were increased with descending to the local bottom, while sand content was decreased. 3. Soils were very strongly to strongly acid and OM, CEC, exchangeable cation, and available $P_2O_5$ in soils seemed to be increased with ascending to the local boctom. 4. Kaolinite and Quartz were the dominant clay mineral and the other was Vermiculite and Illite. 5. Samgag was classified as Typic Dystrochrepts, Sangju as Dystric-Fluventic Eutrochrepts, Sachon as Aeric-Fluventic Halpaquepts, and Yecheon as Fluventic Haplaquepts.

• Journal of Korean Society of Forest Science
• /
• v.110 no.4
• /
• pp.496-503
• /
• 2021

Pinus densiflora is an essential tree species native to the Republic of Korea (ROK) and covers most of the total natural forest areas in the ROK. This study was conducted to understand the site characteristics and stand structure of P. densiflora forests distributed at sites where P. densiflora covered over 50% of the stand basal area during the 7th National Forest Inventory (NFI) period from 2016 to 2020. P. densiflora dominated 3,665 circular sample plots (400 m²). P. densiflora forests predominated at elevations less than 600 m above sea level (a.s.l). However, most P. densiflora forests were distributed at the slopes facing south and west over 800 m a.s.l. At altitudes below 800 m, they were distributed at all slopes but dominated at the southern and western slopes. P. densiflora grew mainly in the soils of sandy loam, loam, or silt loam with relative infertility. Dominant tree species distributed with P. densiflora were Quercus mongolica, Q. variabilis, Q. serrata, Prunus serrulata var. pubescens and Castanea crenata by the descending order. P. densiflora, P. thunbergii, and P. rigida were grown in large DBH classes, Quercus species and Fraxinus rhynchophylla in middle DBH classes, while Juniperus rigida and Styrax japonicus in small DBH classes. Dominant tree species distributed mainly at the lower layer of P. densiflora stands were Rhododendron mucronulatum, Q. serrata, Lindera obtusiloba, Fraxinus sieboldiana, Toxicodendron trichocarpum and Rhododendron schlippenbachii by the descending order.