• Korean Journal of Soil Science and Fertilizer
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• v.11 no.2
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• pp.97-104
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• 1979

According to Soil Taxonomy which has been developed over the past 20 years in the soil conservation service of the U. S. D. A, Soils in Korea are classified. This system is well suited for the classification of the most of soils. But paddy field soils have some difficulties in classification because Soil Taxonomy states no proposals have yet been developed for classifying artificially irrigated soils. This paper discusses some problems in the application of Taxonomy and suggestes the classification of paddy field soils in Korea. Following is the summary of the paper. 1. Anthro aquic, Aquic Udipsamments : The top soils of these soils are saturated with irrigated water at some time of year and have mottles of low chroma(2 or less) more than 50cm of the soil surface. (Ex. Sadu, Geumcheon series) 2. Anthroaquic Udipsamments : These sails are like Anthroaquic, Aquic Udipsamments except for the mottles of low chroma within 50cm of the soil surface. (Ex. Baegsu series) 3. Halic Psammaquents : These soils contain enough salts as distributed in the profile that they interfere with the growth of most crop plants and located on the coastal dunes. The water table fluctuates with the tides. (Ex. Nagcheon series) 4. Anthroaquic, Aquic Udifluvents : They have some mottles that have chroma of 2 or less in more than 50cm of the surface. The upper horizon is saturated with irrigated water at sometime. (Ex. Maryeong series) 5. Anthro aquic Udifluvents : These soils are saturated with irrigated water at some time of year and have mottles of low chroma(2 or less) within 50cm of the surface soils. (Ex. Haenggog series) 6. Fluventic Haplaquepts : These soils have a content of organic carbon that decreases irregularly with depth and do not have an argillic horizon in any part of the pedon. Since ground water occur on the surface or near the surface, they are dominantly gray soils in a thick mineral regolith. (Ex Baeggu, Hagseong series) 7. Fluventic Thapto-Histic Haplaquepts : These soils have a buried organic matter layer and the upper boundary is within 1m of the surface. Other properties are same as Fluventic Haplaquepts. (Ex. Gongdeog, Seotan series) 8. Fluventic Aeric Haplaquepts : These soils have a horizon that has chroma too high for Fluventic Haplaquepts. The higher chroma is thought to indicate either a shorter period of saturation of the whole soils with water or some what deeper ground water than in the Fluventic Haplaquepts. The correlation of color with soil drainage classes is imperfect. (Ex. Mangyeong, Jeonbug series) 9. Fluventic Thapto-Histic Aeric Haplaquepts : These soils are similar to Fluventic Thapto Histic Haplaquepts except for the deeper ground water. (Ex. Bongnam series) 10. Fluventic Aeric Sulfic Haplaquepts : These soils are similar to Fluventic Aeric Haplaquepts except for the yellow mottles and low pH (<4.0) in some part between 50 and 150cm of the surface. (Ex. Deunggu series) 11. Fluventic Sulfaquepts : These soils are extremely acid and toxic to most plant. Their horizons are mostly dark gray and have yellow mottles of iron sulfate with in 50cm of the soil surface. They occur mainly in coastal marshes near the mouth of rivers. (Ex. Bongrim, Haecheog series) 12. Fluventic Aeric Sulfaquepts : They have a horizon that has chroma too high for Fluventic Sulfaquepts. Other properties are same as Fluventic Sulfaquepts. (Ex. Gimhae series) 13. Anthroaquic Fluvaquentic Eutrochrepts : These soils have mottles of low chroma in more than 50cm of the surface due to irrigated water. The base saturation is 60 percent or more in some subhroizon that is between depth of 25 and 75cm below the surface. (Ex. Jangyu, Chilgog series) 14. Anthroaquic Dystric Fluventic Eutrochrepts : These soils are similar to Anthroaquic Fluvaquentic Eutrochrepts except for the low chroma within 50cm of the surface. (Ex. Weolgog, Gyeongsan series) 15. Anthroaquic Fluventic Dystrochrepts : These soils have mottles that have chroma of 2 or less within 50cm of the soil surface due to artificial irrigation. They have lower base saturation (<60 percert) in all subhorizons between depths of 25 and 75cm below the soil surface. (Ex. Gocheon, Bigog series) 16. Anthro aquic Eutrandepts : These soils are similar to Anthroaquic Dystric Fluventic Eutrochrepts except for lower bulk density in the horizon. (Ex. Daejeong series) 17. Anthroaquic Hapludalfs : These soils' have a surface that is saturated with irrigated water at some time and have chroma of 2 or less in the matrix and higher chroma of mottles within 50cm of the surface. (Ex. Hwadong, Yongsu series) 18. Anthro aquic, Aquic Hapludalfs : These soils are similar to Anthro aquic Hapludalfs except for the matrix that has chroma 2 or less and higher chroma of mottles in more than 50cm of the surface. (Ex. Geugrag, Deogpyeong se ries)

• Korean Journal of Soil Science and Fertilizer
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• v.9 no.2
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• pp.107-113
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• 1976

This study is conducted to find out soil erodibility factor K value which is one of the most important factor to estimate soil loss using a new method for predicting K value, the nomograph, that was first proposed by Whischmeier. K values for 83 soil series including upland and forest soils in Korea were checked up. The result were as follows: The average K value was 0.27 with ranging between 0.05 and 0.51. K values were higher for finer textured soils than for coarser textured soils widely ranged in a textural class, and higher for silty textured and low permeable soils. K value was correlated inversely with organic matter content in range of 3 to 13 percent, but the tendency was not related in range of lower than 3 percent.

• Journal of Forest and Environmental Science
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• v.39 no.3
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• pp.180-194
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• 2023

This study characterize, classify and evaluates the function of topography on spatial variability of some selected soil properties to assist in designing land management that support uniform agricultural production. The study site, an agricultural land, was part of the derived savanna zone in southwest Nigeria. Four soil profile pits each were established along two delineated toposequence and described following the FAO/UNESCO guidelines. Samples were collected from the identified genetic horizons. Properties of four soil series developed on different positions of the two delineated Toposequence viz upper, middle, lower slopes and valley bottom positions respectively were studied. The soil samples were analysed for selected physical and chemical properties and data generated were subjected to descriptive and inferential statistics. The results showed that soil colour, depth and texture varied in response to changes in slope position and drainage condition. The sand content ranged from 61 to 90% while the bulk density ranged between 1.06 g cm^-3 to 1.68 g cm^-3. The soils were neutral to very strongly acid with low total exchangeable bases. Available phosphorus value were low while the extractable micronutrient concentration varied from low to medium. Soils of Asejire and Iwo series mapped in the study area were classified as Typic isohyperthermic paleustult, Apomu series as Plinthic isohyperthermic paleustult and Jago series as Aquic psamment (USDA Soil Taxonomy). These soils were correlated as Lixisol, Plinthic Lixisol and Fluvisol (World Reference Based), respectively. Major agronomic constraints of the soils associations mapped in the study area were nutrient availability, nutrient retention, slope, drainage, texture, high bulk density and shallow depth. The study concluded that the soils were not homogenous, shows moderate spatial variation across the slope, had varying potentials for sustainable agricultural practices, and thus, the agronomic constraints should be carefully addressed and managed for precision agriculture.

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.4
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• pp.275-282
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• 1986

A series of studies on the properties of clayey terrace soils distributed at the inland (Yeongcheon) and coastal (Yeongjil) regions in Yeongnam district was carried out. On the base of the facts found and already reported about the macro morphological features as well as on pedological characters in micro scale, physicochemical properties, mineralogical characteristics etc., the present study dealt with soil genesis and tried to classify the soils for reasonable use and managements. 1. Although the both regions belonged to "Mesic" soil temperature regime and "red and yellow earths" areas of "Thornthwaite" pedo-climatic diagram, climatic indices as a soil forming factor indicate that the coastal Yeongil had milder than the inland Yeongcheon. 2. All the terrace soils had developed soil profiles with an "Argrllic B". Upyeong soils in Yeongil region had "Argillans" even in the "II B horizons" that possibly be "Paleo-argillic". 3. The bisequum profiles of Bancheon in Yeongcheon and Upyeong in Yeongil revealed that they were developed on Late Mesozoic shale and on semiconsolidated Tertiary deposits respectively, therefore the overlying clayey terrace deposits were assumed to be originated from the Early Quaternary deposits, Diluvium. 4. To supplement the Soil Taxonomy of USDA, the terrace soils with different degrees of gleyzation were classified as follows; Deogpyeong and Hwadong soils which have less than 50cm of paddified gley horizons (redness less than 0.5) in the upper part of the profiles by artificial surface irrigation, tentatively classified into "Anthrepiaquic Hapludalfs" and the Geugrag soils that have more than 50cm of paddified gley horizons within 1.2m of the profiles, into "Anthr-aquic Ochraqualfs" while the Upyeong soils that had greyish mottles in subsoils by natural ground water remain as an "Aquic Hapludalfs" the same as present. The Bancheon soils with free mottles are into "Typic Hapludalfs" as used at present.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.535-541
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• 2015

Korean soil classification system is based on the US soil taxonomy. This study aimed to understand and inform the soil taxonomy of 2010 and 2014 US soil classification systems. Ingwan series belonged to anthropogenic soil was classified to coarse loamy over sandy, mixed, mesic family of Aquic Udorthents based on the soil taxonomy of 2010 and coarse loamy over sandy, mixed, mesic family of Anthroportic Udorthents based on the soil taxonomy of 2014. An anthropogenic soil is increasing in Korea. Considering the domestic relationship depending on US soil taxonomy, it is important to be well-informed of the taxonomy and apply the updated taxonomy system properly to the domestic soil classification. This study of defining the anthropogenic soil will provide useful information on soil management and its utilization.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.5
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• pp.393-398
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• 2009

This study was conducted to reclassify Yongdang series based on the second edition of Soil Taxonomy : A Basic System of Soil Classification for Making and Interpreting Soil Surveys. Morphological properties of typifying pedon of Yongdang series were investigated and physico-chemical properties were analyzed according to Soil Survey Laboratory Methods Manual. The typifying pedon of Yongdang series has dark reddish brown (5YR 2/3) silt loam Ap horizon (0~14 cm), dark brown (7.5YR 2/3) silt loam BA horizon (14~32 cm), dark brown (7.5YR 2/3) clay loam Bt horizon (32~57 cm), dark yellowish brown (10YR 4/6) silty clay loam Btx1 horizon (57~110 cm), and dark yellowish brown (10YR 4/6) silty clay loam Btx2 horizon(more than 110 cm). That occurs on gently sloping lava plain and is derived from baslt materials. The typifying pedon has an argillic horizon from a depth of 32 to more than 110 cm and a fragipan from a depth of 57 to more than 110 cm. That has a base saturation (sum of cations) of 35% or more at 75 cm below the upper boundary of the fragipan. That can be classified as Alfisol, not as Inceptisol. The typifying pedon has udic soil moisture regime, and can be classified as Udalf. That has a fragipan with an upper boundary within 100 cm of the mineral soil surface, and keys out as Fragiudalf. Also that meets the requirements of Typic Fragiudalf. That has 18% to 35% clay at the particle-size control section, and has thermic soil temperature regime. Yongdang series can be classified as fine loamy, mixed, thermic family of Typic Fragiudalfs, not as fine loamy, mixed, thermic family of Aquic Eutrudepts.

• Economic and Environmental Geology
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• v.45 no.2
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• pp.137-144
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• 2012

Soil pan typically presents the problems in soil water movement or in aeration which is not appropriate for a plant root growth, In this study physico-chemical characteristics of soils and micromorphological characteristic of clay accumulated zone were investigated to identify redox characteristic and evolution of a fragipan of Gangreung series commonly developed in coastal terraces. Gangreung series is classified as Aquic Fragiudalfs according to the USDA soil taxonomy. It is known that sedimentary ocean floor results in soil pan having parallel liner soil structure due to landscape evolution around 200 to 250 million years ago. it is considered that illite, kaolinite, and vermiculite are major clay minerals contained in a fragipan of Gangreung series. Mixed gray and reddish brown colored band around soil pores was found and would be the redoxmorphic features of fragipan. It is possibly due to accumulated illuvial clay and ferriargillans in soil pores and aggregates in reducing conditions eluding ferrous material. Therefore, mixed colored band around pores in soils of Gangreung series would be developed from the eluted ferrous materials which were accumulated in fragipan during the emerged land formation.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.3
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• pp.233-239
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• 1985

The identification works of the clay minerals in the Paju series soil of an alfisol, aquic hapludalf, which is derived from the basalt were carried out by the X-ray diffractometer and with the aid of the complete chemical analysis of the clay fractions as well. It also conducted to determine the contents of the identified minerals which correspond to peaks of the diffraction lines appeared at 0.72, 1.0, and 1.4nm respectively. The expansible 2:1 minerals, micas and micaceous minerals, kaolinite minerals, and gibbsite were identified by the X-ray method. Furthermore, the X-ray results are seemed to be partly supported by the chemical analysis because of the presence of illite in the fractions could be confirmed by the values of $SiO_2/A1_2O_3$ mole ratio which ranged from 2.33 to 2.61. The average contents of the 1.4nm minerals. montmorillonite and vermiculite, 1.0nm micas and micaceous minerals, and 0.72nm kaolinite minerals are 42%, 28%, and 30% respectively. The theoretical considerations for the formations of these minerals were also given and that seemed to be well coincided with the experimental results, The presence of the Bt horizons and the kaolinite with gibbsite equilibria in the soil could be interpreted that the weathering is deeply advanced so far under the given soil environmental conditions.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.536-541
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• 2013

In Soil Taxonomy system, anthropogenic soils are still classified as Entisols since the International Classification Committee for Anthropogenic Soils is in the process of classifying anthropogenic soils as new orders. In reality, it is difficult to characterize anthropogenic soils because Soil Taxonomy (ST) system does not distinguish between natural and anthropogenic Entisols. On the other hand, World Reference Base for soil resources (WRB) considers human impacts on soils and contains an independent category of anthropogenic soils, which makes easier to understand anthropogenic soil characteristics than Soil Taxonomy system. A remodeled paddy field (Gasan) was selected to classify by ST and WRB. Soil samples were taken to analyze chemical and physical properties. Based on the results of the analyses, the ST system classified Gasan as coarse loamy, mixed, mesic, Aquic Udorthents while the WRB did as Stagnic Urbic Technosols (Oxyaquic, Arenic). As a conclusion, the WRB classification information of the anthropogenic provides more detail characteristics of the anthropogenic soils.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.3
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• pp.218-224
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• 2015

Zeolite may help crop growth, yield increase, and salt removal. Field experiment under greenhouse cultivation was conducted to study the effect of zeolite application on growth and yield of Chinese cabbage (Brassica campestris L.) and soil. Soil was classified as Gyuam series (coarse silty, mixed, nonacid, mesic family of Aquic Fluvaquentic Eutrudepts). Six zeolite rates were 0, 3, 5, 10, 20 and $40Mg\;ha^{-1}$. Experimental design was a completely randomized design. Chinese cabbage was grown three times consecutively. Established plant number of plant and yield as fresh weight (F.W.) were measured and soil samples were taken before and after harvesting. Chinese cabbage yield was $76.9Mg\;ha^{-1}$ at a rate of $20Mg\;zeolite\;ha^{-1}$, $54.3Mg\;ha^{-1}$ at a rate of $5Mg\;zeolite\;ha^{-1}$, and $51.3Mg\;ha^{-1}$ at control (no zeolite), respectively. Second order regression analysis using zeolite rate and yield showed that optimum zeolite application rate was between 24 and $26Mg\;ha^{-1}$. The regression equation explained about 88% of the yield variability. The electrical conductivity (EC) decreased from 3.2 to $1.0dS\;m^{-1}$ for all treatments so that salt accumulation was not a concern. Based on the results, we recommend that optimum zeolite application rate is between 20 and $24Mg\;ha^{-1}$ for Chinese cabbage under greenhouse cultivation.