• Korean Journal of Soil Science and Fertilizer
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• v.9 no.2
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• pp.93-98
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• 1976

The present paper is a part of a study aimed at gaining information on the origin, mode of deposition, and characteristics of volcanic soils in Jeju. Volcanic activity of Jeju island has extremely influenced on the formation of various soils. Polysequum phenomenon of soils is one of outstanding soil genesis in Jeju. The typical polysequum soils was collected and analyzed by morphological, physico-chemical, mineralogical and micromorphological approaches The results are as follows: 1. The soils consists of polysequa, A and B horizons from volcanic ashes, unconsolidated volcanic sand layer and B(I) horizons from residual basalts. 2. The lithological discontinuity is also very distinct; silt loam from volcanic ashes, sand (II) from volcanic sand and clayey (III) from basalts. 3. Volcanic sand layer seems to be influenced by lava flow. The properties of it are similar to volcanic ashes rather than beneath residuum in micromorphological aspects. In micromorphological, this layer is gradually changed into soils. 4. Dominant clay minerals are allophane in A and B horizons from volcanic ashes and kaoline, vermiculite and illite from residual basalts. 5. The soils are not developed. There is no formation of argillic horizon in subsurface layers.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.3
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• pp.168-178
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• 1994

Acid sulfate soils occur extensively in Gimhae area where they have been formed from the brackish alluvial sediments along the sea coast and river estuary. The strong acid environment enhances silicate weathering and thus affects the soil clay minerals. The minerals were identified through chemical, X-ray diffraction and thermal methods. The ratio of $SiO_2$ and $Al_2O_3$ in the clay fractions ranged from 3.14 to 3.77, indicating that the distribution of the clay minerals were 1 : 1 and 2 : 1 minerals. Cation exchange capacity in the clay fractions was low due to high contents of 1 : 1 minerals and hydroxy interlayered vermiculite(HIV). The B and C horizon rich in jarosite have large amounts of yellow streaks which reflect high content of $Fe_2O_3$ and $K_2O$. Vermiculite and illite were quantified from thermogravimetry(TG), kaolin minerals from both TG and differential thermal analysis(DTA), and HIV from X-ray diffraction analysis. The dominant clay minerals were kaolin minerals, vermiculite, illite and HIV. HIV considered to be formed, especially, in acid soil environments. The minor minerals were quarts, feldspar, jarosite, pyrite, hematite and goethite. Kaolin minerals were the most abundant clay minerals throughout the acid sulfate soil. Kaolin minerals, however, increased towards the top of horizons throughout the soils and HIV decreased towards the top of horizons in the soil of Gimhae series and Haecheog series. Alteration of HIV to kaolin minerals during weathering of low pH condition in deep soil horizons may explain the high quantities of kaolin minerals and the relatively low quantities of HIV in the soil at top horizons.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.3
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• pp.289-296
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• 1985

To clarify the soil characteristics and genesis of the clayey terrace soils distributed in Yeongcheon (inland region) and Yeongil (coastal region), 9 typifying pedons including a recent local deposits were studied. The physico-chemical properties found were summarized as follows; 1. The contents of available water of the terrace soils were ranged from 12.0 to 20.3%. They were increased with increaseing clay content up to 35%, and then decreased at clay content of 35 to 55%, but were maintained about 12 to 13% when the clay content exceeds 55%. 2. The amount of water stable aggregates in the surface soils were ranged from 55.0 to 81.1%, and were low in cultivated upland where water erosion were accelerated while high in the paddy where the double cropping were practiced. The index of aggregate in cultivated upland were higher in the surface soils but the paddy soils were higher in subsoils. 3. The colloidal reactions checked by the differences between pH in $0.01N-Na_2SO_4$ and $H_2O$ indicate exchangeable acidity to exchangeable neutrality, which means a sort of Red-yellow soil forming process had been prevailed during genesis of the terrace soils. 4. Cation exchange capacity of the clayey terrace soils were averaged about 15.8-20.2me/100g of fine earth and 35.6-52.6me/100g of clay. The rates of base saturation were 32.7 to 57.6% and the rates decreased with increasing the elevations of terraces. 5. The activities of free iron oxides were 0.061 to 0.739 and the values decreased with increasing elevation while the crystallinity index of iron oxides positively correlated with elevations the values ranged from 0.067 to 0.537.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.916-921
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• 2011

This study was carry out on a Jang-Won series (fine loamy, mixed, mesic family of typic fragipan) that were established and classified as a fragipan soil in Korea. The morphological, physical, chemical and minerals characteristics of Jang-Won series were studied to determine the genesis of fragipan soils in natural environment. Each sample was analyzed for its physical, chemical and mineralogical characteristics. The particle size distribution of samples was measured using pipette method. Clay minerals were investigated on parallel-oriented specimens of the clay fraction ($<2{\mu}m$) from each horizon, separated by sieving and centrifugation, using X-ray diffraction (XRD) analysis. Micromorphological observations were made on thin sections prepared from soil blocks impregnated with Crystic Resin, cut and ground to less than $30{\mu}m$ in thickness, and finally polished with diamond paste. Most horizons have pH values in the range of fewer than 5.0 and have very low base-saturation values. Their textural classification ranges from silt loam to loam, the lower horizons being the finer. The clay fraction revealed the occurrence of illite, kaolinite, chlorite and vermiculite. The micro-morphological analysis carries out thin sections from each soil profile. The silt concentrations occur as extremely dense and homogenous bands or zones of silt-sized materials, brownish in colour in plane-polarized light and anisotropic in cross-polarized light, surrounding or adhering to skeleton grains. The genesis of fragipan in the Jangweon series assumed composition of clay fraction rather than silt concentration. Therefore, this results suggested an authentic interpretation which Jangweon series is classification as Typic Fragiochrepts.

• Korean Journal of Soil Science and Fertilizer
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• v.1 no.1
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• pp.129-136
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• 1968

Low-Humic Gley Soils occur very commonly in Korea and constitute important paddy soils of the country. These soils are developed either on alluvial or fluvio-marine materials. The soils in the present invest igation are derived from the latter. The interesting morphological features of these two soils are the presence of $FeCO_3$ concretions in the subsoil and the occurrence of a buried black organic horizon of variable thickness(25-100 cm). The organic horizon overlies the greenish marine material and underlies the continental material. These soils have poor drainage and are wet most of the year. The presence of $FeCO_3$ concretions in poorly drained paddy soils has previously been reported in North America(8), Japan(9) and West Europe(7). The purpose of this investigation is to study the chemical and mineralogical characteristics of these soils; and the genesis of $FeCO_3$ concretions. Profile samples of both these soils were collected from Gimjae area, in co-operation with the Soil Survey Party. These profiles were described as follows:

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.3
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• pp.191-194
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• 1992

The tomb of the king Muryung, the 25th king of ancient Baegje dynasity in Korea, was proved to be constructed about 1500 years ago. The Physico-chemical characteristics were determined in order to investigate the pedogenic process for tomb soils. Clay and silt content inclosed down to 30~40cm soil depth. The increase of clay was 13.4% in the 10cm surface soil and the estimated time for 1% increase of clay in the profile was about 112 years. There were great changes in chemical properties in the 10cm surface soil, and considerable accumiration of salts and increase of catiom exchange capacity(CEC) down to 30cm depth. The alteration of primary minerals and formation of clay minerals were great in the 10cm surface soil and considerably reconized down to 50~60cm. The result suggested that the development of soil profile from the tomb parent material for the period was 10cm under the forest environment in Korea. The parent material of tomb soil was considered to be transported greyish green clored diorite from other place.

• Korean Journal of Soil Science and Fertilizer
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• v.12 no.2
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• pp.99-107
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• 1979

The properties, land use and genesis of the Jang-weon series, Planosol-like soils, distributed in Cheong-do area were investigated. Planosol-like soils in Korea have been believed unsuitable for perennial crops but 34.6% (594ha) of the Jang-weon soils in Cheongdo-gun are used for perennial crops such as apples, persimmons, peaches, mulberry etc. With productivity more or less equal to alluvial soils. The reason for high productivity and a working hypothesis for the genesis of the fragipan is suggested with discussion.

• Journal of Conservation Science
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• v.7 no.2
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• pp.68-79
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• 1998

The protecting-chamber for a standing Buddha of Mireuk-ri temple site at Jungwon is composed of granite of Cretaceous age which mainly consists of quartz, perthite, plagioclase, and biotite with minor amounts of muscovite, apatite, chlorite, sericite and opaque mineral. There are abundant cracks which may be developed by strong weathering and differential loading by structural unbalances of the whole protecting-chamber. Cracks can be divided into three types based on genesis as those formed by exfoliation, intrinsic, and pressure. The exfoliation occurred along the onion structure of the granite. The pressure cracks are generally superimposed on the exfoliation ones, which might be developed by structural unbalance of the protecting-chamber resulted from differential loading in places. The structural unbalance may be due to change in physical properties of the rocks according to strong weathering, differential settling of basement soil by difference in loading in places of protecting-chamber, westward creep of the basement soil below the West wall and related different resistance of the basement soil against the loading, and partial depression of the West wall. For the conservation of the protecting-chamber, it must be considered the method of stabilizing the basement and treatment of the cracks.

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.3
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• pp.205-210
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• 1986

A soil micromorphological study of clayey terrace soils in Yeongnam area was carried out to investigate the soil genetic features and to distinguish the soil parent materials. Dominant plasmic fabrics in the terrace soils were vosepic, mosepic, insepic, and masepic of sepic fabrics but the Geugrag and Upyeong in Yeongil sequence have an asepic fabrics. Embedded grain cutans in the terrace soils were characterized by having porphyroskelic related distribution. Among pedological features of the B horizons of the terrace soils, the argillic cutans of ferriargillans and glaebules of manganiferrous concretions were the dominant in mineralogical composition, and the papules are abundant in the most terrace soils indicating that the soils are generally old. The substrata of the Bancheon in Yeongcheon and Upyeong in Yeongil area were so different from the terrace deposits in plasmic fabrics that these soils were believed to be composed of bisequum profiles. Because of having the free grain cutans, it was considered that the substrata of Bancheon in Yeongcheon and Upyeong in Yeongil area might have a period of soil formation before deposition of the terrace materials.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.2
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• pp.177-188
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• 1985

To clarify the characteristics and genesis of clayey terrace soils in Yeongnam area, macro-morphological features and soil profile development indexes were investigated with the sequential soils in Yeongcheon (inland region) and in Yeongil (coastal region). The results are summarized as follows; 1. According to the physiogaphy and landuse, the terrace soils were discernible to well drained yellowish red (5 YR) profile of higher terrace (Bancheon series), moderately well drained reddish yellow (7.5 YR) profile of middle terraces (Upyeong and Hwadong series), and lower terraces (Deogpyeong and Geugrag series) which were moderately well to imperfectly drained by paddy-fication. 2. The roundness and sphericity of the gravels contained in the terrace deposits were ranged around 0.543-0.546 and 0.723-0.722, respectively. The rounded to well rounded gravels were resemble to typical alluvial origins. 3. The amount of clay minerals formed in the soil horizons per 100g of parent materials were 50.8-30.7g while the rates of the clay leached were 30.1-7.4%, and the higher terrace had the more leaching rates. 4. The index of profile development of the terrace soils ranged from 37.95 to 22.01 and the index were positively correlated with relative elevations of the soils. The rates of clay leaching were positively correlated with the ratios of clay in the illuvial horizons to elluvial horizons. 5. A similarity was observed among cumulative grain size curves of the terrace soils, but the patterns of recalculated silt free cumulative grain size curve of terrace deposits in Upyeong soils in Yeongil area were abruptly different from down layer that suggest the soil to have bisequum profile.