• Journal of the Mineralogical Society of Korea
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• v.15 no.1
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• pp.33-43
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• 2002

Mineral composition and chemical properties of Hwangto (reddish residual soil) that used in feeding of cattles at Iksan, Jeollabuk-do, Korea were examined according to particle size separation such as gravel, sand, silt, coarse clay and fine clay. Mineral composition analyses reveal that gravel and sand are mainly composed of quartz and feldspars and that kaolin mineral and illite are dominant in clay and silt. Iron oxides are mainly included in fine clay. According to chemical analyses of major elements, Al, Fe and $H_2O$ contents are increased with decreasing of particle size. This trend well agrees with increase of clay minerals in smaller particles, Chemical analyses of trace elements indicate that contents of Zn, Rb, Sr, Ba, Pb significantly differ with particle sizes. Ba and Sr are included in feldspars since these elements are abundant in sand containing abundant feldspars. Pb and Sm are abundant in sample before particle size separation, but the contents are significantly decreased after separation. Therefore, most of these elements appear to be existed as removable phase. Nb, La, Th, Ce are more abundant in silt. The contents of all the other trace elements tend to be increased in smaller particles containing more clay minerals. The contents of changeable cations and teachable elements in acid and alkali solutions are high in clay samples. All the above results indicate that using the portion of smaller particle of Hwangto for livestock feed rather than bulk Hwangto can improve cation exchangeable capacity, ion leaching capacity and sorption properties.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.3
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• pp.77-91
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• 2015

This study aims to suggest adequate soil management through the analysis of physicochemical properties of soil in the planting grounds of Incheon International Airport, which was constructed on a massive land reclamation site. Study areas were 5 sites at the international business complex, the passenger terminal, the airport support complex, the free trade zone, and the access road. Soil profile analysis showed that 9 plots out of the 27 plots were hardpan and heterospere within 80cm from the soil surface. The earth laid on the ground was categorized as gravel based soil(4 plots), dredged soil from the sea bottom and mixed reclamation materials(2 plots), clay with poor permeability(3 plots) and waste construction material(1 plot). Average soil hardness was $11.5kg/cm^2$ and soil textures were sandy soil, sandy loam and loamy sand. Average soil pH was 6.7 and average organic matter content was 0.7%. Electrical conductivity was 0.0dS/m and exchangeable cation concentrations were $Ca^{2+}$ 3.4cmol/kg, $Mg^{2+}$ 1.5cmol/kg, $K^+$ 0.3cmol/kg and $Na^+$ 1.0cmol/kg. Average cation exchange capacity was 11.0cmol/kg. Although average figures in Solum mostly meet the landscape design criteria, properties of each soil layer showed various values sometimes over the limit. Base saturations were $Ca^{2+}$ 29.9%, $Mg^{2+}$ 13.3% and $K^+$ 3.7% for lower soil, $Ca^{2+}$ 33.3%, $Mg^{2+}$ 17.0% and $K^+$ 2.7% for mid-soil and $Ca^{2+}$ 32.6%, $Mg^{2+}$ 12.2% and $K^+$ 1.9% for upper soil. Exchangeable sodium percentages were 16.4% for lower soil, 7.5% for mid-soil and 4.7% upper soil. Sodium adsorption rates were 0.8 for lower soil, 0.3 for mid-soil and 0.2 for upper soil. Factors affecting to the vegetation growth were heterogeneity and poorness of solum, disturbance of dredged soils, high soil hardness including hardpan in the subsurface soil layer and shallow effective soil depth, high soil acidity, imbalance of base contents, low organic matter content and low available phosphate levels in the soil.

• Journal of Korean Society of Forest Science
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• v.109 no.2
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• pp.157-168
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• 2020

The sensitivity of forest soil to acidification in the Republic of Korea (ROK) was evaluated based on pH_H2O, cation exchange capacity (CEC), and base saturation (BS). Sensitivity to acidification was categorized into three grades: adequate level (AL, pH ≧ 4.2, CEC ≧ 15cmol/kg, BS ≧ 15%), caution level (CL, at least one indicator is below AL), and severe Level (SL, all three indicators are below AL). Soil samples were collected from the 65 stationary monitoring plots (40 × 40 ㎢), distributed throughout ROK. Only 19% of soil samples were classified as AL, while 66% and 15% were CL and SL, respectively. The median of pH_H2O, CEC, BS, and Ca/Al indicator in AL soils was pH 4.64, 20.7cmol/kg, 29%, and 6.3, respectively. Moreover, BC_ex (K⁺, Mg²⁺, Ca²⁺) and available phosphorus (AP) concentration compared with a threshold value and molar ratio of BC_ex and AP to total nitrogen (TN) was high. This indicates that AL soils have a good nutrient condition. The molar Ca/Al ratio, an indicator for toxicity of exchangeable aluminum (Al_ex), was more than 1, indicating no negative impact of Al_ex on plant growth. On the contrary, the median of pH_H2O, CEC, and BS in SL soils was pH 4.02, 13.2cmol/kg, and 10%, respectively. The Ca/Al index was less than 0.6, which indicates that negative impacts of Al_ex on plants were high. Furthermore, both the concentration of BC_ex in SL soils and the BC_ex/TN ratio were the lowest among the three acidity degrees. This shows that SLsoils can be degraded by soil acidification compared with less acidic soils.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.5
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• pp.364-370
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• 2009

This study was conducted to survey, analyze on the compaction layer and the plow layer at Jeonbug and Jisan series paddy soil, which is the representative soil in fluvio-marine and local alluvium, respectively. The depths of surface soil were 12.6 and 12.7 cm in Jeonbug and Jisan series, respectively. A plowing depth was 10.5 cm. The properties of compaction layer in two soil series were as follows. The hardness were $14.7kg\;cm^{-2}(25.3mm)$ and $8.7kg\;cm^{-2}(22.1mm)$ in Jeonbug and Jisan series, respectively. The thickness were 22.3 cm and 17.8 cm in Jeonbug and Jisan series, respectively. The depth of soil compaction, which means depth from surface, were 15 and 20 cm in Jeonbug and Jisan series, respectively. The relationship between the hardness of compaction layer and the depth of surface soil showed negative correlation, however relationship between the hardness and the thickness of compaction layer showed positive correlation. Soil temperature was lower in compaction layer than in plow layer. This temperature differences between compaction layer and plow layer were from 1.0 to $2.5^{\circ}C$ in Jeonbug series and from 0.7 to 2.1 in Jisan series. The soil physical properties of compaction layer were higher in bulk density and solid phase and lower in porosity and gaseous phase than those of plow layer in all soil series. The soil chemical properties of compaction layer were higher in pH, content of available silicate, exchangeable calcium and magnesium but lower in total nitrogen, content of organic matter and available phosphate than those of plow layer in all soil series. Cation exchangeable capacity and content of exchangeable potassium were similar between compaction layer and plow layer in Jeonbug series, however, in Jisan series these were lower in compaction layer than in plow layer. Elution amount of inorganic nitrogen were lower in compaction layer than in plow layer in all soil series. The content of soluble Fe and Mn were plenty in compaction layer compared with plow layer and these tendency was apparent in Jeonbug series. The water depth decrease were fast until the latter part of June, and were slow as $1{\sim}3mm\;day^{-1}$ for July and August, and were fast again from september. Rice roots distributions as each soil series and tillage method were 25 cm at rotary plowing in Jeonbug series, 30 cm at deep plowing in Jeonbug series, and 20 cm at tillage in Jisan series. Dry weight per m2 at heading stage were much in order of deep plowing in Jeonbug series, rotary plowing in Jeonbug series, and tillage in Jisan series.

• Economic and Environmental Geology
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• v.54 no.4
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• pp.409-425
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• 2021

Carbon dioxide has been known to be a typical greenhouse gas causing global warming, and a number of efforts have been proposed to reduce its concentration in the atmosphere. Among them, carbon dioxide capture and storage (CCS) has been taken into great account to accomplish the target reduction of carbon dioxide. In order to commercialize the CCS, its safety should be secured. In particular, if the stored carbon dioxide is leaked in the arable land, serious problems could come up in terms of crop growth. This study was conducted to investigate the effect of carbon dioxide leaked from storage sites on soil fertility. The leakage of carbon dioxide was simulated using the facility of its artificial injection into soils in the laboratory. Several soil chemical properties, such as pH, cation exchange capacity, electrical conductivity, the concentrations of exchangeable cations, nitrogen (N) (total-N, nitrate-N, and ammonia-N), phosphorus (P) (total-P and available-P), sulfur (S) (total-S and available-S), available-boron (B), and the contents of soil organic matter, were monitored as indicators of soil fertility during the period of artificial injection of carbon dioxide. Two kinds of soils, such as non-cultivated and cultivated soils, were compared in the artificial injection tests, and the latter included maize- and soybean-cultivated soils. The non-cultivated soil (NCS) was sandy soil of 42.6% porosity, the maize-cultivated soil (MCS) and soybean-cultivated soil (SCS) were loamy sand having 46.8% and 48.0% of porosities, respectively. The artificial injection facility had six columns: one was for the control without carbon dioxide injection, and the other five columns were used for the injections tests. Total injection periods for NCS and MCS/SCS were 60 and 70 days, respectively, and artificial rainfall events were simulated using one pore volume after the 12-day injection for the NCS and the 14-day injection for the MCS/SCS. After each rainfall event, the soil fertility indicators were measured for soil and leachate solution, and they were compared before and after the injection of carbon dioxide. The results indicate that the residual concentrations of exchangeable cations, total-N, total-P, the content of soil organic matter, and electrical conductivity were not likely to be affected by the injection of carbon dioxide. However, the residual concentrations of nitrate-N, ammonia-N, available-P, available-S, and available-B tended to decrease after the carbon dioxide injection, indicating that soil fertility might be reduced. Meanwhile, soil pH did not seem to be influenced due to the buffering capacity of soils, but it is speculated that a long-term leakage of carbon dioxide might bring about soil acidification.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.3
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• pp.249-254
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• 1992

This research was conducted to investigate the effects of fly ash applications on growth and yield parameters of corn (Zea mays L.), and soil chemical properties. Corn height at silking stage, and height and dry matter ratio at harvesting stage were enhanced by applications of fly ashes derived from bituminous coal and anthracite, respectively. Effects of fly ash treatment on growth parameters of corn were varied with kinds and levels of fly ash application and growth periods, but relatively small without revealing a major negative effect as compared to the control. Yield of corn was increased by applying fly ash of anthracite origin, but other yield components were not influenced negatively by fly ash treatment. Soil total carbon contents, cation exchange capacity, and phosphorus contents of soils sampled after harvest of corn were significantly increased by fly ash treatment, although there were slightly different effects according to kinds and levels of fly ash application. Exchangeable cations of soils were varied within an experimental error range. Phosphorus taken up by corn was enhanced by treating fly ash of the bituminous coal to the soil and there were a positive correlation between phosphorus uptake and soil Phosphorus level. Cation uptake by corn was changed a little, but no significant reduction was observed in cation uptake due to fly ash treatment. It seems to be difficult to figure out the mechanism of fly ash effects on growth and nutrient uptake by corn with one year field experiment, however treatment of fly ash enhanced some parameters of growth and yield, and nutrient uptake by corn without revealing any major negative effects. To determine the value of fly ash as a fertilizer source, continuous researches under various soil and crop conditions were considered to be necessary.

• Journal of the Korean Geotechnical Society
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• v.27 no.10
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• pp.81-92
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• 2011

The rheological properties of Wyoming bentonites are strongly influenced by the size of particles, cation exchangeable capacity, arrangement and morphology of clay mineral. This paper presents the results of rheological investigations on the Wyoming bentonites aqueous dispersions: two types of particle flocculation were considered. For the Wyoming bentonite, 0g/L and 30g/L NaCl equivalent salinity were added in fresh and salt water to examine the rheological behavior. This paper examined the general rheological characteristics, compatibility of rheological models and correlation between soil structure and change in rheological properties of Wyoming bentonite caused by increasing salinity. From flow curves of bentonites hydrated with fresh water and salt water, the observed general flow behavior is very close to shear thinning with yield stress (or ideal Bingham fluid with yield stress and plastic viscosity). However, the change of shear stress at the same shear rate is clear, particularly for lower shear rate. Well-known rheological models are used to fit the data. There is a good agreement between rheological model and data: Carreau, Herschel-Bulkley and power-law for S=0g/L and bilinear, Herschel-Bulkley and power-law for S=30g/L. It may be due to the fact that the internal structural bonding (strong modification of particle-particle interactions from edge-to-edge and/or edge-to-face to face-to-face) in soil matrix is affected from the evolution of rheological properties with different salinities.

• Korean Journal of Organic Agriculture
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• v.21 no.4
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• pp.753-767
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• 2013

Soil contamination has continuously increased worldwide, thus the remediation for the contaminated soils has risen steadily. However, the consideration of ecological safety for the remediated soils and their agricultural uses has been very limited. Therefore, this study was to investigate the influences of selected environmentally-friendly agricultural materials, organic by-product fertilizer (OF), charcoal (CC), and biochar (BC), as soil conditioners for improving poor chemical properties of fuel-oil removed soil by land farming technique. Two different remediated soils, remediated soil A (RSA) and remediated soil B (RSB), were selected. Soil texture of both RSA and RSB was sandy loam. The chemical properties of RSA and RSB were as follows: soil pHs of 8.5 and 8.7, soil organic matter contents of 7.4 and 5.5g $kg^{-1}$, total nitrogen contents of 0.26 and 0.10g $kg^{-1}$, available phosphorus concentrations of 7.2 and 4.4mg $kg^{-1}$, and exchangeable calcium concentrations of 14.8 and $11.7cmol_c$ $kg^{-1}$, respectively. Results of the properties were not reached for the optimal values for cultivating crops that were recommended by National Academy of Agricultural Science at Rural Development Administration in Korea. However, after applying OF, CC, and BC, the chemical properties of soils were selectively improved, which were that soil organic matter content and available phosphorus concentration increased, whereas the soil pH were not changed. In particular, the chemical properties were positively changed more with the application of 5.0% biochar. Thus, continuous management of the remediated soils with applying the eco-friendly agricultural materials can improve the quality of reme-diated soils.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.1
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• pp.23-28
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• 1987

A series of field and laboratory experiments were conducted to find out the changes of some soil chemical constituents in different soil depth with three different soil textures as Bongnam-clayey, Gwanghwal-silty loam and Mangyeong fine sandy soil on the assessment of reclamation duration in Fluvio-marine soil. The result obtained were summarized as follows; 1. Exchangeable potassium, calcium, magnessium, sodium with manganes, silica and cation exchange capacity were remarkably decreased with assessment of reclamation duration. Decreasing tendency was pronounced more in sandy soil than silty loam or clayly soil. 2. Soil organic matter content in top soil was increased with increasing of reclamation years. From reclamation time, about 30 years in clayly and about 80 years in silty loam and sandy soil were necessary for the maintanance of averaged organic matter content to 2.5%. 3. Potassium activity ratio ($K/{\sqrt{Ca+Mg+Na}}$) was differed with soil depth, soil texture and assessment of reclamation duration. About 50 years is may be necessary for the maintanance of potassium activities ratio in ordinary paddy soil of 0.05-0.2. 4. Percent of adsorbed sodium (PAS), ratio of adsorbed sodium (RAS) and ratio of sodium adsorbtion(RSA) were remarkably decreased with assessment of reclamation duration. Specially, decreasing tendency was pronounced more in sandy soil than silty loam and clayly soil 5. Amount of clay content in subsoil was appearently decreased during 30 years of reclamation, but clay contents in top soil was appearently decreased 50 years after reclamation.

• Korean Journal of Environmental Agriculture
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• v.17 no.3
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• pp.211-214
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• 1998

Changes in physico-chemical properties and major nutrient contents were investigated in the soil of paddy fields during fallow period. Weed vegetation change in the fallow paddy fields was also examined. As the fallow period became longer, organic matter content in the paddy soil has gradually increased. Soil pH of the paddy fields has not changed until three years of fallow period and thereafter slightly increased. Cation exchange capacity of the paddy soil, and exchangeable N, K, Ca and Mg contents in the soil tended to decrease until three years of fallow period and then increase with the prolonged fallow period. As the fallow period became longer, available $P_2O_5$ content in the paddy soil has continuously decreased. Available $SiO_2$ content in the paddy soil has not changed until three years of fallow period and thereafter increased. The vegetation in the fallow paddy fields have mostly been occupied by the weeds of the Gramineae, Cyperaceae, and Compositae. As the fallow period became longer, the weeds of the Polygonaceae and Juncaceae have increased, whereas the weeds of the Leguminosae, Commelinaceae, Pontederiaceae, and Onagraceae have gradually disappeared. However, the weeds of the Gramineae and Cyperaceae have always been dominant in the paddy fields during the fallow paddy period.