• Korean Journal of Soil Science and Fertilizer
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• v.30 no.2
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• pp.200-207
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• 1997

In order to evaluate the soil microbiological characteristics of paddy fields in Korea, surface soils were sampled from 63 sites in different agroclimatic zones before submersion of the fields. The distribution of microorganisms and the microbial diversity indices were examined. Soil microbial populations were generally higher in southern area than in northern area. The colony forming units(cfus) of fluorescence Pseudomonas sp. showed the greatest regional differences, among the microbes investigated. On the topographical differences, the cfus of aerobic bacteria, fluorescence Pseudomonas sp. and Azotobacter sp. maintained high level in coastal plains; and on the sail textural difference, fungus was the highest in clay soil, but Bacillus sp., Azotobacter sp and denitrifiers were the highest in silty clay loam soil at 0.05 probability level based on the multiple range test. The numbers of ammonium oxidizers and Azotobacter sp. were increased with soil pH. Microbial diversity indices of paddy fields which calculated from the percentages of Bacillus sp. fluorescence Pseudomonas sp. Azotobacter sp. denitrifiers, ammonium oxidizers, nitrite oxidizers, actinomycetes and fungus to these total microbial numbers were between 0.109 and 0.661. On the soil textures, the microbial diversity indices of sandy, sandy loam, silty clay loam, clay loam and clay soil were 0.443, 0.427, 0.414, 0.405 and 0.362 respectively.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.84-88
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• 2007

우리나라의 토양조사는 미농무성(USDA)의 분류방법에 따라 개략토양조사($'65{\sim}'67$년), 정밀토양조사($'68{\sim}'79$년), 논토양배양사업 10개년계획($'80{\sim}'90$년), 그리고 밭토양세부정밀토양조사($'95{\sim}'99$년) 등을 실시하였다. 현지에서의 토양조사는 지형, 배수등급, 토성, 자갈함량, 유효토심, 경사 등 현지의 지형지물 및 환경을 통하여 많은 정보를 얻을 수 있으며, 이를 통하여 전국에 대한 토양조사 결과, 토양통 (심토의 특성이 유사한 토양) 390개, 토양구(표토의 토성을 세분) 536개, 토양상(경사도 및 침식등급을 세분) 1,321개로 분류되어 있다. 우리나라 토양형성 발달에 미친 기후인자는 습윤권역(Udic moisture regime)과 토양온도는 mesic과 일부 남해안과 제주지역의 thermic인 토양온도(Soil moisture regime)였으며, 식생인자는 높은 지역의 경우에는 산림이 낮은 저지대 평탄지는 자연초지가 대부분이다. 지형인자는 동고서저지형으로 동부는 산악지, 서부는 경사가 완만한 구릉지며, 한강 등 대부분이 서남방향으로 흐르는 지형이다. 모재는 다양하나 70%이상이 화강암, 화강편마암이 주를 이루고 있었다. 시간인자의 경우에는 기간이 매우 오래되었으나, 지형이 복잡하여 토양발달이 약한 Inceptisol과 층위발달이 없는 Entisol이 대부분이며, 다음으로 Ultisol과 Alfisol이 뒤를 이었다. 일부 Andisol, Mollisol, Histosol이 존재하였다. 우리나라의 토양분류는 Soil Taxonomy에 의해 분류되었는데, 이것은 토양의 단면내에 존재하는 감식층위(Diagnostic Horizon)의 유무 및 종류에 따른 분류이다. 토양분류 결과 최고 상위분류 단위인 목(order)이 7개, 아목(suborder) 14개, 대군(great group) 27개, 아군(sub group) 67개, 속(family) 161개로 분류되었으며, 가장 저차단위인 통(series)이 390개 분류되었다. 또한 작물이용측면에서 실용적 분류를 실시하였는데, 논토양의 경우 보통논, 미숙논, 사질논, 습논, 염해논, 특이산성논으로 분류할 경우 각각의 분포면적이 31.9%, 23.0%, 31.9%, 9.1%, 3.9%, 0.2%이었다. 밭토양의 경우에도 보통밭, 사질밭, 미숙밭, 중점밭, 고원밭, 화산회밭으로 6개 유형으로 분류할 경우 각각의 분포면적은 41.9%, 23.3%, 17.5%, 13.9%, 1.1. 2.2% 이었다. 도시화 및 도로확대 등 다양한 토지이용 및 지형개변으로 과거의 토양정보가 많이 변경되었다. 그래서, 앞으로는 인공위성자료 및 항공사진을 이용하여 빠르고 쉽게 활용할 수 있는 토양조사 방법개발과 기 구축된 토양도의 수정, 보완 작업이 필요한 절실히 요구되고 있는 현실이다.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.1
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• pp.39-48
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• 1977

The results of the determination of the optimum level of nitrogen fertilizer experiment for rice paddy at 21 locations over the country in 1975 year are as follows. 1. The yields of control and N-fertilized plots of ordinary variety (Japonica type) were normal paddy soil>sandy paddy soil>poorly drained paddy soil. Control plots of Tongil variety, (Indica type) however, were sandy poorly drained soil>sandy normal paddy soil=clay poorly drained soil, and N-fertilized plots were normal paddy soil>sandy poorly drained soil>sandy soil>clay poorly drained soil. In other words Tongil variety has higher adaptability to sandy soil under no nitrogen. 2. The yield response to N-fertilizer was higher in normal paddy soil than sandy soil. The productivity per 1kg of nitrogen was 16.6kg in normal paddy soil, 10.5 in sandy soil, and 8.6-11.4 in poorly drained soil for Tongil variety. For ordinary variety, they were 12.6, 6.3, 6.6-9.3kg respectively. 3. Ripening ratio for ordinary variety and ripening ratio and grain weight for Togil variety were higher in sandy soil than normal paddy soil. The main reason why the N-response in mormal paddy soil is higher was appeared to be higher number of effective tillers in normal paddy soil. 4. The optimum rates of N-fertilizer in average were 19.4 in normal paddy soil, 14.6 in sandy soil, and 11.6-13.4kg/10a in poorly drained soil for Tongil variety. For ordinary variety they were 15.9, 10.2, and 8.7-12.7kg/10a respectively. 5. The optimum rate of nitrogen was increased with the increase of productivity in normal paddy soils. In sandy soils and poorly drained soils it was not proved. 6. The optimum rates of N-fertilizer calculated from field experiment were somewhat different from the optimum rates calculated from $SiO_2/OM$ ratio. However, the values calculated both ways showed high correlation. It would be recommendable, therefore, to use $SiO_2/OM$ ratio to calculate the optimum rates of N-fertilizer after revising this equation considering different rice varieties and soil types or water management and climate.

• 한국문화재보존과학회:학술대회논문집
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• 2004.03a
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• pp.71-77
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• 2004

• Journal of the Korean GEO-environmental Society
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• v.15 no.4
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• pp.37-41
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• 2014

Pulse electrokinetic technology is proposed for improving the dewatering-process from clay-sandy soil. Proposed electrokinetic technology is to be the dewatering process due to fluid movement of current flow for the stability of clay-sandy soils. Samples produced in this study were completed to verify the proposed performance for 7 days by gradually increasing the pressure to the final pressure of 30 psi ($2.11kgf/cm^2$) through the compression process. In this study, pulse electrokinetic treatment and conventional continuous electrokinetic treatment are tested and observed, respectively. The condition of continuous electrokinetic treatment is a continuous process during 48 hours. And the condition of pulse electrokinetic treatment system is to interrupt the power three times for 48 hours, every 8 hours. These treatments are that the voltage gradient is 3 V/cm. As a result, the efficiency of pulse electrokinetic is similar to the continuous electrokinetic. The power consumption efficiency of pulse electrokinetic is better than continuous electrokinetic.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.4
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• pp.337-342
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• 1984

224 profiles representing 19 soil series were subjected to multiple regresion analysis to determine the relative contribution of organic matter(OM) and clay content to total cation exchange capacity(CEC) in sandy soil. The independent variables were OM and clay, with the dependent variable CEC. Simple correlation coefficients showed high significance at CEC-OM and CEC-clay. The partial regression coefficients indicated that CEC for each gram of OM was calculated to be 0.549 and 1.351 meq of top and subsoil. The clay contributions of top and subsoil were 0.247 and 0.226 meq, respectively. The standard partial regression coefficients appeared that clay content was 1.23 times as important as orgnic matter in predicting CEC.

• The Korean Journal of Quaternary Research
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• v.3 no.1
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• pp.35-45
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• 1989

In Korean peninsula as well as in Western European Countries, we can find, reddish bands in sandy deposits of various origin. These bands (called "$B_t$ Band"), composed of fine material, are regularly intervalled and parallel to topography. This study is tring to elucidate their origin and associated milieux, with a group of methods and techniques (field survey, micromorphological analysis, granulometry, X-ray diffractometry of clay minerals...). $B_t$ Bands are not sedimentological origin. They were formed by superposition of two type accumulations in the sandy profile, triggered by different mechanisms: 1) accumulation in banded form, concerning silty heterometric material and micas, oweing to cryophoretic forces operating in course of deep freezing of sandy deposits: 2) illuviation of ferrugineous clays in the precedants bands, migrated in chelate state by soil water. The first processes are associated with very cold and humid climate in which freeze soil more than 3m in depth. The second, cold and humid climate in which podzolizattion is generalized. In case of South Korea and Western Europe, these two types of climates are not present circumstance, but Recent Quaternary (probably since the Wurm).the Wurm).

• Journal of the Korean Society of Groundwater Environment
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• v.5 no.3
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• pp.155-161
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• 1998

Retardation effect of heavy metals in soils caused by adsorption onto the surfaces of solids particles is well known phenomenon. In this study, we investigated the retardation effect on the mobility of a Zn in a sandy soil by conducting batch and column tests. The column test consisted of monitoring the concentrations of effluent versus time known as a breakthrough curve (BTC). We used NaCl and ZnCl$_2$ solutions with the concentration of 10 g/L as a tracer, and injected them respectively into the inlet boundary of the soil sample as a square pulse type, and monitored the effluent concentrations at the exit boundary under a steady state condition using an EC-meter and ICP-AES. The batch test was conducted based on the standard procedure of equilibrating fine fractions collected from the soil with various initial ZnCl$_2$ concentrations, and analysis of Zn ions in the equilibrated solutions using ICP-AES. The results of column test showed that i) the peak concentration of ZnCl$_2$analyzed by ICP was far less than that of either NaCl or bulk electrical conductivity and ⅱ) travel times of peak concentrations for two tracers were more less identical. The relatively low concentration of Zn can be explained by ion exchange between Zn and other cations, and possible precipitation of Zn in the form of Zn(OH)$_2$due to high pH range (7.0∼7.9) of the effluent. The identical result of travel times of peak concentrations indicates that the retardation effect is not present in the soil. The only way to describe the prominent decrease of Zn ion was to introduce decay or sink coefficient in the CDE model to account for irreversible decrease of Zn ions in the aqueous phase.

• 한국문화재보존과학회:학술대회논문집
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• 2005.03a
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• pp.71-88
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• 2005

With biological organism brown pollutants layers are thickly formed on inner stone materials in Gyeongjuseokbinggo(Ice storage in Gyeongju). Some simples were taken from this layer and its chemical composition, mineral composition, salt and microstructures were analyzed. This study shows that the pollutants layer can be removed easily, because it attached softly in stone surface. But because of its serious weathering state the stone surface also can be removed during the removing process. The origins of brown layer are assumed to be the soil in the mound over the Seokbinggo and the coarse sandy soil in the entrance. For the preservation of the Seokbinggo Waterproof and replacement of the coarse sandy soil should take precedence over the remove works. Subsequently moistureproof works should be enforced.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.05a
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• pp.101-107
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• 2000

Column tests using KCl and Benzene as tracers were conducted for four different cases: 1) no hydrogen peroxide and no microorganism; 2) hydrogen peroxide only; 3) microorganism only; 4) hydrogen and microorganism to investigate the sorption and degradation characteristics of Benzene. The observed BTCs of KCl and Benzene in all cases showed that the arrival times of the peaks of both tracers coincided well but the peak concentration of Benzene was much lower than that of KCl. This result reveals that a predominant process affecting the transport of Benzene in a sandy soil is an irreversible sorption and/or degradation rather than retardation. Decay of Benzene through sorption and degradation increased with the addition of hydrogen peroxide and/or microorganism. Dissolved oxygen decreased with the increase of Benzene in all cases indicating that Benzene was degraded by dissolved oxygen. For BTCs with the addition of microorganisms (case 3 and case 4), microorganism showed much lower concentrations compared to the initial levels and an increasing tendency with time although concentrations of Benzene returned to zero, indicating a possible retardation of microorganism due to reversible and irreversible sorption to the particle surfaces.