• Journal of The Geomorphological Association of Korea
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• v.19 no.2
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• pp.187-195
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• 2012

Daisetsuzan National Park in Hokkaido, Japan, has an extensive alpine region due to the topographic feature of lava plateau, and exhibits the surface geology largely composed of pyroclastic materials. In addition, the peak season of mountain climbing in the park coincides with a snow-melting period, resulting in severe soil erosion along hiking trails generated by human trampling, snow-melting water and pipkrake. Trail section has been particularly enlarged because the snow-melting water scours a trail surface and the pipkrake erodes sidewalls of a trapezoid-shaped trail. The scoured tread also forces hikers to walk out of a trail, and then frequently brings about path divergence as well as path widening. The soil particles, which are produced by erosional processes in a slope reach, flow downward, and cause the secondary trail degradation by covering a tread in a flat reach and nearby grassland.

• Journal of Soil and Groundwater Environment
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• v.27 no.1
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• pp.50-59
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• 2022

There are several methods for separating the baseflow from the hydrograph, and graphical methods (GM) have mostly been used. GMs are those that separate the baseflow from the direct flow simply by connecting rising point with inflection point or points related to some duration from a hydrograph. Environmental tracer method (ETM) is another tool researched and developed under several conditions to estimate the groundwater recharge. The goal of this study is to separate the baseflow component from a storm hydrograph by applying various GMs and ETM, and to compare their results. The baseflow component estimated by ETM was different from the results by GMs in terms of their shapes of fluctuation and flow rates. Another important feature is that the form of the baseflow to which ETM is applied is similar to that of a storm hydrograph. This similarity is presumed to be due to the selection of tracer that respond quickly to rainfall.

• The Korean Journal of Quaternary Research
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• v.11 no.1
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• pp.57-68
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• 1997

Climatic change of the late-Quaternary period has been record-ed in the loess deposits of the central Great plains and the record of such change is extractable using a number of approaches and parameters. The stratigraphy of loess deposits which have been investigated on Fort Riley exhibits the same sequence of loess units and intercalated buried soils as is found elsewhere in the re-gion but adds detail unique to the reservation Upland late-Qua-ternary composite stratigraphy preserved on the reservation con-sists of the basal Sangamon soil of the Last interglacial(c. 120-110ka), Gilman Canyon Formation(c. >40 -20ka), Peoria loess(c. 20 -10ka) Brady soil(c. 11 -10ka) Bignell loess(c. 9-\ulcornerka). and mod-ern surface soil. Application of magnetic analyses has provided proxy data sets that represent a time series of climatically regulated pedogenesis/weathering and botanical composition. magetic data have yielded an impression of the variation in climate from Sangamon time to the late Holocene through a reconstruction of the history of pedogenesis/weathering. Sangamon soil formation dominated the reservation durin the Last interglacial as indicated by magnetic parameters. During Gil-man Canyon time loess influx was usually sufficiently slow as to permit pedogenesis which appears to have been at a maximum twice during that time. Warm season grasses were important dur-ing soil formation but diminished in importance during the peri-ods of more rapid loess fall which were cooler and perhaps wet-ter. Peoria loess fall a function of the deterioration of climate during the last Glacial Maximum thinly blanketed the reservation with thickest accumulations occurring to the north-west(Bala Cemetery site)proximal to the source region. Long-term surface stability did not apparently occur within Peoria time but short-term stability may be indicaed by the presence of thin weathering zones(incipient soils) in the Peoria loess. Re-gional landscape stability prevailed during the environmental shift at the Pleistocene/Holocene transition resulting in forma-tion of the well expressed Brady soil. One or more weak soils developed in the Bignell loess as it ac-cumulated. A notable feature of the Bignell loess is the appear-ance of the Altithermal dry period: the loess experienced little weathering and was dominated by warm season grasses until the latter of the Holocene.

• Journal of Microbiology and Biotechnology
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• v.18 no.6
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• pp.1011-1015
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• 2008

A Gram-negative, strictly aerobic, motile bacterial strain, designated Gsoil $124^T$, was isolated from a soil sample taken from a ginseng field in Pocheon Province (South Korea). The isolate contained Q-10 as the predominant lipoquinone, plus $C_{18:1}\;{\omega}7c$ and summed feature 4 ($C_{16:1}\;{\omega}6c$ and/or iso-$C_{15:0}$ 2-OH) as the major fatty acids. The G+C content of the genomic DNA was 68.1 mol%, and the major polar lipids consisted of sphingoglycolipid, phosphatidylglycerol, phosphatidylcholine, and phosphatidylethanolamine. A comparative 16S rRNA gene sequence analysis showed that strain Gsoil $124^T$ was most closely related to Sphingopyxis chilensis (98.7%), Sphingopyxis alaskensis (98.2%), Sphingopyxis witflariensis (98.2%), Sphingopyxis taejonensis (98.0%), and Sphingopyxis macrogoltabida (97.6%). However, the DNA-DNA relatedness between strain Gsoil $124^T$ and its phylogenetically closest neighbors was less than 22%. Thus, on the basis of its phenotypic properties and phylogenetic distinctiveness, strain Gsoil $124^T$ should be classified as representing a novel species in the genus Sphingopyxis, for which the name Sphingopyxis panaciterrae sp. nov. is proposed. The type strain is Gsoil $124^T$ (=KCTC $12580^T$=LMG $24003^T$).

• Journal of Microbiology and Biotechnology
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• v.20 no.1
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• pp.15-20
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• 2010

A Gram negative, aerobic, nonspore-forming, straight or curved rod-shaped bacterium, designated Gsoil $317^T$, was isolated from soil of a ginseng field in Pocheon Province (South Korea) and was characterized using a polyphasic approach. Cells were dimorphic, with stalk (or prostheca) and nonmotile or nonstalked and motile, by means of a single polar flagellum. Comparative analysis of 16S rRNA gene sequences revealed that strain Gsoil $317^T$ was most closely related to Caulobacter mirabilis LMG $24261^T$ (97.2%), Caulobacter fusiformis ATCC $15257^T$ (97.1 %), Caulobacter segnis LMG $17158^T$ (97.0%), Caulobacter vibrioides DSM $9893^T$ (96.8%), and Caulobacter henricii ATCC $15253^T$ (96.7%). The sequence similarities to any other recognized species within Alphaproteobacteria were less than 96.0%. The detection of Q-10 as the major respiratory quinone and a fatty acid profile with summed feature 7 ($C_{18:1}\;{\omega}7c$ and/or $C_{18:1}\;{\omega}9t$ and/or $C_{18:1}\;{\omega}12t;$ 56.6%) and $C_{16:0}$ (15.9%) as the major fatty acids supported the affiliation of strain Gsoil $317^T$ to the genus Caulobacter. The G+C content of the genomic DNA was 65.5 mol%. DNA-DNA hybridization experiments showed that the DNA-DNA relatedness values between strain Gsoil $317^T$ and its closest phylogenetic neighbors were below 11%. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain Gsoil $317^T$ should be classified as representing a novel species in the genus Caulobacter, for which the name Caulobacter ginsengisoli sp. novo is proposed. The type strain is Gsoil $317^T$ (=KCTC $12788^T=DSM\;18695^T$).

• Korean Journal of Environmental Agriculture
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• v.22 no.1
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• pp.53-59
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• 2003

The present study was conducted to analyze the vegetational difference in fellowed fields at the different seral stages. Plant species were surveyed on the fields having different cropping history, soil moisture conditions, and the duration of set-aside. Effects of soil moisture condition and fellowing duration on the vegetational profiles of fellowed fields in the course of different seral stages. In the fields fellowed for more than three years, a conspicuous feature of vegetation was the dominance of perennial species, which was less dominant in the fields fellowed for less than 3 years. The floristic composition of fellowed fields was dependent on the soil moisture condition. However, the influence of fallow-history on vegetational composition was less than that of the soil moisture conditions. The dominant species occurred in fellowed upland (dry) fields were changed from Glycine soja, Persicaria thunbergiana, and Artemisia princeps at 2-year-fellowed to Persicaria thunbergiana, Miscanthus sinensis, and Glycine soja at 6-year-fellowed. In wet fellowed paddy fields, annual Mosla punctulata, Ambrosia artemisiifolia, and Setaria viridis, the dominant species at 3-year-fellowed, were substituted by perennial Miscanthus sinensis, Aster pilosus, and Hemarthria sibirica at 7-year-fellowed. When the succession continued for 11 years in wet fields, the vegetation was characterized by the domination of perennials such as Phragmites communis, Zizania latifolia, and Typha orientalis. It was suggested that the soil moisture condition was a strong determinant of the dominant species on early seral conditions. In the fellowed paddy fields, the species diversity was relatively higher in the fields set-asided as wet condition compared to the fields fellowed as dry condition.

• Korean Journal of Soil Science and Fertilizer
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• v.11 no.4
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• pp.247-262
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• 1979

Majority of reclaimable soils in hillside lands in Korea are red yellow soils, with exception in Jeju island, where most of reclaimable hillside lands are composed of volcanic ash soils. Songjeong, Yesan and Samgag series are the major soil series of red yellow soils which are available for the reclamation. When observed in the fields, they are distinguished as reddish brown clay loam, red yellow sand loam and yellowish brown sand loam. They have moderately good physical properties but their chemical properties are generally poor for crop cultivations. The chemical properties of red yellow soils, as compared to long time cultivated (matured) soils, are characterized by very low pH, high in exchangeable Al content and phosphorus fixation capacity. Also extraodinary low available phosphorus and organic matter contents are generally observed. On the other, the chemical properties of volcanic ash soils are characterized by high armophous Fe and Al hydroxides and organic matter contents, which are the causative factors for the extremely high phosphorus fixation capacity of the soils. The phosphorus fixation capacity of volcanic acid soils are as high as 5-10 times of that of red yellow soils. Poor growth of crops on newly reclaimed red yellow soils are mainly caused by very low available P and pH and high exchangeable Al. Relatively high P fixation capacity renders the failure of effective use of applied P when the amount of application is not sufficient. Applications of lime to remove the exchangeable Al and relatively large quantity of P to lower the P fixation capacity and to increase the available P are the major recommendations for the increased crop production on red yellow hillside soils. Generally recommendable amounts of lime and P to meet the aforementioned requirements, are 200-250kg/10a of lime and $30-35kg\;P_2O_5/10a$. Over doses of lime. frequently induces the K, B, arid Zn deficiencies and lowers the uptake of P. In volcanic ash soils, it is difficult to alter the exchangeable Al and the P fixation capacity by liming and P application. This may be due to the peculiarity of volcanic ash soil in chemical properties. Because of this feature, the amelioration of volcanic ash soils is not as easy as in the case of red yellow soils. Application of P as high as $100kg\;P_2O_5/10a$ is needed to bring forth the significant yield response in barley. Combined applications of appropriate levels of P, lime, and organic matter, accompanied by deep plowing, results in around doubling of the yields of various crops on newly reclaimed red yellow soils.

• Journal of Korea Society of Digital Industry and Information Management
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• v.15 no.2
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• pp.19-28
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• 2019

The purpose of this study is to examine the trends on machine learning and deep learning research in the published journals from the Web of Science Database. To achieve the study purpose, we used the abstracts of 20,664 articles published between 1990 and 2017, which include the word 'machine learning', 'deep learning', and 'artificial neural network' in their titles. Twenty major research topics were identified from topic modeling analysis and they were inclusive of classification accuracy, machine learning, optimization problem, time series model, temperature flow, engine variable, neuron layer, spectrum sample, image feature, strength property, extreme machine learning, control system, energy power, cancer patient, descriptor compound, fault diagnosis, soil map, concentration removal, protein gene, and job problem. The analysis of the time-series linear regression showed that all identified topics in machine learning research were 'hot' ones.

• Korean Journal of Plant Taxonomy
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• v.49 no.3
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• pp.265-268
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• 2019

An unrecorded Fissidens species, Fissidens protonemaecola Sakurai (Fissidentaceae, Bryophyta), was newly discovered in Korea during an investigation bryophyte flora. In this study, we examined the morphology of F. protonemaecola in Korea. This species was found in soil along a train through a shaded backslope of Mt. Bukbyeongsan (elev. 80 m) on Geojedo Island and on Mt. Gogeunsan (Oreum; elev. 280 m) on Jejudo Island, Korea. This species has dwarfish bud-like shoots scattered on persistent protonemata. An important feature of the protonemata is a diagnostic character of F. protonemaecola that clearly distinguishes it from other Fissidens species. Its Korean name is given as "Cho-rok-sil-bong-hwang-i-kki," inferred from the characteristic protonemata of the species.

• Journal of Forest and Environmental Science
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• v.26 no.3
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• pp.181-192
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• 2010

Water erosion is progressing in the Loess Plateau, especially in gullies, and the sediment runoff to the Yellow River amounts to 975 million tons every year. Natural factors for water erosion include climate, soil, geological feature, terrain and vegetation. Many development projects due to the increasing population reduced the forest coverage ratio to 10%, and 200 million people in the downstream area are suffering from the damage during intense rainfall. Accordingly, the Chinese government is continuously trying to efficiently prevent the erosion by establishing measures for water erosion, including fish-scale pits, terrace technique, and check dams.