• Korean Journal of Soil Science and Fertilizer
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• v.22 no.2
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• pp.116-121
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• 1989

An experiment on movements of copper in soils was conducted to evaluate the effectiveness of several soil extractants in predicting to be possibly the plant availability of copper in soils. Soil samples were taken six, from Las Virgines loam that the samples naturally included high contents of heavy metals near Los Angeles, Greenfield sandy loam and IDomino Loam that received 22.5, and $45.0mg.\;ha^{-1},\;yr^{-1}$ of composted sludge from Los Angeles from 1975 to 1983, respectively. Copper in soils were extracted with $4M\;HNO_3$, 0.1M HCl, 0.5M DTPA-0.1M TEA, 0.5M EDTA-0.1M $Ca(NO_3)_2$, and 1M ammonium acetate(pH 7), and analyzed by atomic absorption spectroscopy. The results were as follows: 1. The total copper contents in soil that received $45.0mg.\;ha^{-1},\;yr^{-1}$ of composted sludge were higher than that received $22.5mg.\;ha^{-1}.yr^{-1}$, regardless of soil samples. 2. The ratios of extractable copper contents with EDTA, DTPA, 0.1M HCl and 1M ammonium acetate to total copper contents extracted with 4M $HNO_3$ of long-term sludge applications were larger than those of natural, sludge-nontreated soils. 3. Statistically significant increase in total copper contents was found in the increasing values of multipling CEC, or OM% by R, ratio of extractable copper contents to those by 4M $HNO_3$ extraction as total copper contents in soils.

• Korean Journal of Environment and Ecology
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• v.17 no.3
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• pp.242-257
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• 2003

This study surveyed an ecosystem conservation area that is wetland area to establish ecological restoration and preservation plan. Monitoring standard have been set up item, method, period, number of times etc. Result that examine according to monitoring standard, Plant field investigated Flora, actual vegetation. Flora is 132 taxa(39 family 116 species 19 variety 1 forma) appeared and wild species were 85 species, and introduced species were 47 species. Grasped monthly(April∼September) actual vegetation, swampy plant community influence were increase and influence of Persicaria thunbergii was big situation specially. Frequency appearance of naturalized plant is much on field. Animal field investigated Birds, Herpetofauna, Insecta. Birds were appeared 34 species 378 individual and Herpetofauna were appeared 4 species 5 individual and insecta investigated 11 order 52 family 153 species. Inorganic environmental field investigated groundwater level, quality of water, soil quality. Groundwater level is high by 0.0∼89.0cm, $Ca^{++}$ content is some high by 2.18∼13.73cmol/kg in soil. Also we suggested basis direction and each space details plan on monitoring as follow : wetland ecosystem restoration plan, eruption area restoration plan, forest ecosystem restoration plan.n.

• Korean Journal of Organic Agriculture
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• v.23 no.3
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• pp.595-604
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• 2015

Soil chemical properties in paddy fields were found to be varied depending upon different cultivation methods such as environmentally-friendly, conventional, and two-crop farming systems and different topographical regions, namely plain, middle mountainous, and reclaimed land regions. Overall soil pH was found to be in optimal range (pH 5.5~6.5) for rice cultivation, except with conventional cultivation fields of the reclaimed lands in Jeonnam province. Electrical conductivity (EC) was relatively higher in the two-crop cultivation fields than in others. However, the concentrations of available phosphate as $P_2O_5$ were exceptionally higher in the two-crop farming fields, thus in submerged paddy condition the phosphate could be released into streams and rivers. Soil organic matter (SOM) contents were mostly in optimal range ($25{\sim}30g\;kg^{-1}$) for paddy field in Jeonbuk province, but in Jeonnam province they were slightly higher values of the range. The concentrations of available silicate ($SiO_2$) were mostly depended on the cultivation methods and the region, but some of paddy fields contained extremely high $SiO_2$ concentration. Statistical relationships among the soil chemical properties showed as follows: Correlations between EC values and exchangeable cation concentrations, between SOM contents and CEC values, and between available $SiO_2$ concentrations and pH, EC, exchangeable cations, and CEC values were positively significant, whereas total nitrogen concentrations were significantly negatively correlated with the concentrations of exchangeable K and Mg. These results might be very useful to establish benchmark paddy fields contained with certain levels of soil fertility.

• Journal of the Economic Geographical Society of Korea
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• v.15 no.2
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• pp.192-205
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• 2012

This study estimates how much climate variables affect the land price and acreage of rice paddy and dry farm field in agriculture with the case of Gangwon-do in Korea. To this end, we capitalize upon the Ricardian approach based upon the panel data on climate, soil and geography, farmland prices and acreage, other economic and social variables for 11 municipal units comprising Gangwon-do during the period of 1992-2010. Our empirical analysis shows that the temperature variable has negative economic impacts on the price and acreage of rice paddy and dry farm field, confirming that the temperature variable is much significant than that of precipitation in global warming. On the other hand, the other determinants of farmland price and acreage are different with the type of farmland in Gangwon-do.

• Microbiology and Biotechnology Letters
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• v.27 no.6
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• pp.427-432
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• 1999

For the development of a multifunctional biocontrol agent, the siderophore-producing strain GL7 was isolated from a rhizosphere on chrome azurol S agar. The GL7 was identified as a strain of Pseudomonas fluorescents on the basis of their reactions to standard physicochemcial tests from Bergey's manual, API diagnostic test, and fatty acid analysis. P. fluorescents GL7 considerably inhibited spore germination and hyphal growth of phytopathogenic fungus Funsarium solani in a dual culture. In pot trials of bean with P. fluorescens GL7, the disease incidence was significantly reduced down to 5% from 70% of incidence in the untreated control. P. fluorescens GL7 also enhanced plant growth to nearly 1.5 times than that of the untreated control, promoting elongation and development of the roots. These results suggest that the plant growth-promoting P. fluorescens GL7 can play an important role in the biological control of soil-borne plant disease in a rhizosphere.

• Korean Journal of Soil Science and Fertilizer
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• v.23 no.1
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• pp.15-20
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• 1990

A laboratory experiment was conducted to investigate the relationship between the composition of phosphorus forms and soil chemical properties. The soil samples were collected from the farms of the 149 locations where vegetables were intensively cultivated with heavy application of phosphorus. The composition percentages of Ca-P and Saloid-P to the total phosphorus were increased as increasing soil pH while those of Fe-P and Al-P were decreased, The composition percentage of Fe-P were increased up to pH 5.0-6.0 and decreased as increasing pH above 6.0. respectively. The pH dependency of Al-P and Fe-P composition percentage was more remarkable for the soils with high available phosphorus (>500ppm) than with low available phosphorus (<500ppm). Composition percentages were in order of Fe-P>Al-P>Ca-P>Saloid-P for the soils with available phosphorus below 500ppm, while those were in order of Al-P>Fe-P>Ca-P>Saloid-P for the soils with high available phosphorus above 1,000ppm. Composition percentages of Al-P and Fe-P were increased as increasing active Al content, and Fe-P was increased as increasing of active Fe and P sorbed but saloid-P, Al-P and Ca-P were decreased.

• Korean Journal of Environmental Agriculture
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• v.34 no.2
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• pp.77-90
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• 2015

BACKGROUND: The field margins, which are uncultivated area of permanent vegetation located adjacent to field, play an important role in enhancing biodiversity in the agricultural ecosystem. This study focused on floristic characteristics on dry field margins in Korea Peninsula. METHODS AND RESULTS: This study was conducted at margins of 196 dry fields in 32 areas in 8 provinces in May and September 2013. The vascular plants of the dry field margins were listed 347 taxa which contain 73 families, 219 genera, 311 species, 1 subspecies, 30 varieties and 5 forms. Of these 347 taxa, 48 taxa were woody plants and 299 taxa were herbaceous plants. Among total 73 families, Compositae (17.6%) was the most dominant family, and followed Gramineae (15.9%), Polygonaceae (5.8%), Leguminosae (4.9%) and Cyperaceae (3.8%). Based on relative frequency values of survey fields, the appearance frequency of Digitaria ciliaris (89.8%) was the highest, and followed Acalypha australis (86.2%), Artemisia princeps (82.1%), Commelina communis (80.6%) and Portulaca oleracea (80.6%). Disturbance index of dry field margins was 55.0% at national level, and Gangwon region was the highest among the 8 regions at regional level. Life form spectrum was determined to be $Th-R_5-D_4-etype$. CONCLUSION: These results will be used fundamental data for studies to improve or even stabilize the current state of plant biodiversity in agricultural environments.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.431-433
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• 2004

해수 영향을 받은 연구지역 지하수의 특성을 수리지화학적 분석과 다변량 통계분석방법을 이용하여 고찰하였다. 수리지화학 분석 결과, 연구지역 지하수는 크게 해수와 경작 등에 의한 인간활동의 영향을 받고 있음을 알 수 있었다. Cl, Na, Mg, Ca, HCO$_3$, NO$_3$, SO$_4$, K, SiO$_2$, Sr의 농도값을 이용하여 군집분석과 주성분 분석 결과, 연구지역의 지하수는 해수의 영향을 나타내는 Na, Cl에 의해 크게 영향을 받으며 3개의 그룹으로 나누어지고, 각 그룹별로 다른 특성을 보여줌을 알 수 있었다.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.3
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• pp.278-286
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• 1995

Phosphate-solubilizing microorganisms were isolated from agricultural area in Korea, and the solubilizing potential of microorganisms was evaluated in vitro. Of the several microorganisms Pseudomonas putida, Penicillium sp., and Aspergillus niger showed solubilization in all phosphatic compounds such as hydroxyapatite, tricalcium phosphate, aluminium phosphate and rock phosphate tested. Inorganic P solubilization was directly related to the pH drop by each microorganisms. Aspergillus niger was found to be more active in solubilizing phosphate than Pseudomonas putida and Penicillium sp.. The maximum concentration of phosphorus released from each of aluminium phosphate, hydroxyapatite and tri-calcium phosphate by Aspergillus niger in liquid culture was 776ppm, 665ppm and 593ppm, respectively when $KNO_3$ was added as nitrogen source. For rock phosphate, it was 411ppm with ammonium sulfate as nitrogen source.

• Korean Journal of Organic Agriculture
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• v.15 no.2
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• pp.219-228
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• 2007

강원도 고랭지는 채소 재배지로 그 이용 면적이 매년 급속히 증가하고 있다. 금한 경사와 집중적으로 발생하는 장마철의 폭우는 토양 유실은 물론이고 토양 비옥도의 심각한 저하를 초래할 위험이 경작의 강도와 범위가 넓어짐에 따라 더욱더 증가하고 있다. 또한 험한 지형에 따른 기계화 영농의 어려움과 이에 수반하는 노동력의 낭비로 문제점을 제기한다. 채소 작물 재배를 위해 많이 사용하는 요소 비료, 황산암모늄 비료와 함께 특별히 수지(resin)를 피막 처리한 복합비료를 가지고 배추의 생장과 토양에 미치는 영향을 조사하였다. 수지 피막처리는 각각 7, 10, 15%의 비율로 혼합했다. 배추의 수량은 실험에 사용된 비료간에 큰 차이가 없었다. 요소와 황산암모늄은 기본 시비와 함께 2차례 추비를 하였고 수지 피막 복합 비료는 단 한번 초기에 시비하였다. 따라서 이 경우 노동력 절감과 토양 환경 교란의 최소화를 달성할 수 있었으므로 완효성의 수지 피막 처리 비료가 바람직한 것으로 나타났다. 토양에 미치는 효과는 비료의 종류간에 별다른 차이가 없었으나 인산$(P_2O_5)$의 토양내 축적 현상이 t지 피막 처리 복합 비료 시용 구에서 뚜렷하게 조사되었다. 일반적으로 화학 비료의 시용은 토양 반응(pH)의 저하를 초래하였다.