• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.338-341
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• 2003

유기염소계 농약 중 대표적인 살충제 $\delta$-BHC(hexachlorocyclohexane)와 1, 2-DCB (1, 2-dichlorobenzene)에 대한 논, 밭 토양 및 풍화 토에 흡착 배치실험을 통하여 토양 특성과 유기오염물간의 흡착 관계를 규명하였다. 13개의 토양시료에 대하여 pH, CEC, 유기물 함량, 비표면적, 입도분석, 원소조성분석을 통하여 토양의 물리ㆍ화학적 특징이 토양 흡착에 미치는 영향을 규명하고자 하였다. 유기염소계 농약의 흡착량을 Freundlich isotherm으로 나타내어 흡착분배계수(K$_{d}$)를 산출하였다. $\delta$-BHC는 유기물 함량이 높은 soil-4$_{d}$에서 가장 높은 $K_{d}$ 값을 보였으며, 1,2-DCB의 경우 CEC, 비표면적이 가장 낮은 soil-5에서 낮은 $K_{d}$ 값을 보여 토양 내 유기물 함량과 비표면적이 유기오염물 흡착량에 중요한 요소로 작용함을 알 수 있었다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.362-365
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• 2002

토양의 물리/화학적 특성에 따른 토양의 유기오염물 흡착능 변화를 규명하기 위하여, 토양 내 clay 함량 및 유기물 함량변화, 수용액 내 TCE 농도변화에 따른 TCE 의 토양내 흡착량 변화를 측정하였다. 수용액의 pH와 실내온도는 일정하게 유지시켰으며 clay는 표면적이 다른 Ca-montmorillonite, Na-montmorillonite, kaolin을 이용하였고, 유기물질로는 활성탄을 사용하였다. 일정한 토양성분과 실제토양에 대해 수용액 내 TCE의 농도를 변화시켜 농도변화에 따른 흡착량 변화를 측정하였다. 실험결과 유기물과 점토함량의 증가에 따라 흡착량은 모두 증가하였으나 활성탄에 의한 TCE 흡착량이 점토에 비해 매우 높았으므로 유기물에 의한 TCE 흡착영향이 점토에 의한 흡착 영향보다 큰 것으로 나타났다. TCE 농도변화에 따른 흡착결과는 실제토양과 모사토양에서 모두 농도가 증가함에 따라 흡착 증가율이 증가하다가 감소하는 Langmuir isotherm 형태를 보여 주었다.

• Korean journal of applied entomology
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• v.38 no.1
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• pp.47-52
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• 1999

Effects of organic matter content in soil on activity. vertical migration. and persistence of two nernaticides. carbofuran and ethoprophos. to root-knot nematode, Mrloitlog!~iei ~lcognita.w ere investigated. As the organic matter content increased. activity of the nernaticides tended to be reduced. Both nematicides exhibited control values of more than 80'k' to M. iix.o,yilit~iln 0-2 cm depth soil layer from the surface. regi~rdless of organic matter content in soil. In 2-4 cm depth soil layer. however. the control value of the neniaticides varied with the organic niatter content in soil. The control value of carbofuran in the soil layer was ranged from I0 to 30'2,. depending on the soil organic niatter content. In contrast. ethoprophos had no control value against M. i/ic.o,ytlitcr in the \oil layer, except that the nematicide had a control value of 30% when the organic matter content was 0.4%. Furthermore. ethoprophos had no effect on controlling M. i/ic.o,gtiitrr in soil layer of below 4cm. whereas control values of carbofuran were approximately from 5 to 20% in all test soils having different organic matter contents. These results indicate that carbofuran has more vertical migration effect than ethoprophos. Persistence of the two neniaticides was also decreased with increasing soil organic matter content. Half life of carbofuran was 2-3 weeks in soil containing 0.4% organic matter, whereas it was found to be I week in soils containning 0.8 ant1 1.6% of organic matter. On the other hand. activity of ethoprophos was reduced to half in 3-3 weeks and in 2-3 weeks in soil containing 0.4 and 0.8%, and 1.6%) of organic matter, respectively. However, no activity of the both nernaticides was found in soil containing 3.2% of organic matter.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.2
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• pp.85-92
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• 2000

The purpose of this study was to identify the controlling factors to construct tidal flat ecosystems having similar characteristics as natural ones. We transplanted the soil in a constructed tidal flat to a natural one and vice versa. Parameters monitored after these transplantations were silt content, organic matter, bacterial population and oxidation-reduction potential. Moreover, the relationship among silt content, organic matter and bacterial population was investigated by laboratory column experiment. The silt content, organic matter, bacterial population and vortical profile of oxidation-reduction potential in the soil transplanted from the constructed tidal flat to the natural one changed to similar values to those In the natural one. On the contrary, all the parameters for the soil transplanted from the natural tidal flat to the constructed one changed to similar values as those in the constructed one. The silt contents in these two transplanted soils were in proportion to the organic carbon contents and bacterial population. Similarly, the bacterial population in laboratory column experiment increased with the increase in silt and organic matter contents. It seemed to be important to select a place to enhance accumulative of silt and/or to maintain the silt content by hydrodynamic control of seawater in order to construct a tidal flat having similar characteristics as natural one.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.4
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• pp.69-76
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• 2016

To produce the primary data for best management of soil nutrient in organically practiced soils, 75 leading organic farms whose paddy fields were certified as organic were selected. Soil samples were collected from the paddy fields before plowing, and then analyzed for the determination of physico-chemical properties. Soil pH, organic matter and available phosphate were analyzed and averaged 6.2, $25.6mg\;kg^{-1}$ and $88.4mg\;kg^{-1}$, respectively. Contrary to the national-scale-surveyed paddy soils including organic and conventional farming, pH was higher, available phosphate was lower in the organically practiced soils, but organic matter was similar. With the increasing cultivation period in organic, soil pH and porosity were also increased, EC, available phosphate, bulk density and soil hardness were lower than those from the national survey. Organic matter, however, was not significantly changed. The bulk density was negatively correlated with the organic matter content for both surface topsoil ($R^2=-0.5424$) and subsoil ($R^2=-0.6429$) (p<0.05). Soil quality is improved in most of soil chemical and physical composition factors excluding organic matter and available phosphate. However, it is necessary to establish the counter measure plan for organic matter management and to develop phosphate-containing materials which can be used as organic agricultural material in the future.

• Korean Journal of Soil Science and Fertilizer
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• v.11 no.3
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• pp.145-160
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• 1979

The effects of organic material application on soil physical properties were reviewed in relation to soil productivity. The organic matter contents and soil physical properties of the cultivated land in Korea were summarized and the effects of organic matter were compared in terms of land uses and soil types. Soil physical properties related to crop yield potential, such as soil aggregation, permeability, water holding capacity, erodibility, and compactibility, were used in evaluating the effects of organic materials as a soil physical amendment. The benefical effects of organic matter addition on soil physical conditions include (1) better aeration and increased infiltration in silty and clayey soils, (2) increased water holding capacity and moisture availability in sandy soils, (3) decreased soil erodibility, and (4) increased resistance to compaction. It is, therefore, concluded that continuous application of organic materials could greatly improve the various soil physical properties and favor the growth and yield of crops. A high rate of organic matter addition could contribute to reducing not only the soil erosion on sloping land, but also the possible detrimental effect of farm mechanization. In general, the effects of organic matter on soil physical improvement were estimated to be much higher in upland than in paddy. Organic matter would have a more pronounced effect on low productive lands such as heavy clayey or sandy soils and newly reclaimed soil. The optimum level of soil organic matter content was estimated to be about 3.0 to 3.5% for the best soil physical condition. Since the organic matter contents of the cultivated lands in Korea are much lower than optimum level, it would be desiable to use more organic materials to soil for the increase of soil productivity, continuation of stabilized high productivity and soil erosion control.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.4
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• pp.234-241
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• 2007

Biological amendments consisting of suspensions of selected microorganisms are often used in conjunction with various organic materials for amending soils to improve soil quality and plant growth. The effects of the biological amendment on chemical and biological properties of soil were investigated for a biological amendmentalone and when combined with different organic materials includingmunicipal compost (MC), poultry litter (PL), and cover crops (red clover (RC) and spring oats). A liquid preparation of a biological amendment called Effective Microorganisms was sprayed on the tested plots three times over a two-year period. Effective Microorganisms alone did not influence pH, K, or organic matter content in soil. However, increases in P in PL-treated soils in fall of both years andCa in MC-treated soil in fall 2001, and decreases in Ca, Mg, and cation exchange capacity (CEC) in RC-planted soil were associated with EM. Increased dehydrogenase(DH) activitiesassociated with Effective Microorganismswere only detected in July (P=0.0222) and October (P=0.0834) for RC-planted soils in the first year. Fluorescein diacetate (FDA) hydrolysisappeared to be enhanced by Effective Microorganisms in soils untreated or treated with MC and oatsbut only sporadically during the sampling period. FDA hydrolysis in both PL- and RC-treated soils as well as DH activity in PL-treated soils decreased with Effective Microorganisms treatment. Effective Microorganisms did not influence substrate utilization patterns expressed by the BIOLOG assay. We conclude that Effective Microorganisms effects on soil chemical and biological properties varied depending on the added organic materials. Effective Microorganisms periodically increased soil DH activity and FDA hydrolysis with RC and with MC plus oats, respectively.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.567-575
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• 2018

The soil physical quality is a core factor in achieving two of sustainable agriculture's goals: productivity and environment. The purpose of this study was to assess changes in soil physical properties for nearly a decade through periodic monitoring of three cultivation types: upland, orchard, and paddy. Field surveys and lab analysis were conducted to determine the soils physical properties after every 4 years; upland (2009, 2013, and 2017), orchard (2010 and 2014), and paddy (2011 and 2015). In each year soil samples from 162-338 sites were collected. The bulk density of upland subsoil decreased from $1.53Mg\;m^{-3}$ to $1.50Mg\;m^{-3}$ while the plowing depth and subsoil organic matter increased from 13.7 cm to 19.5 cm and from $12.6g\;kg^{-1}$ to $18.3g\;kg^{-1}$ respectively during the period 2009-2017. Plowing depth for orchard increased from 16.7 cm to 18.9 cm. However, organic matter content decreased from $15.9g\;kg^{-1}$ to $15.4g\;kg^{-1}$ during the 2010-2014 period. For paddy, plowing depth and subsoil organic matter decreased from 17.5 cm to 16.7 cm and from $17.5g\;kg^{-1}$ to $15.8g\;kg^{-1}$ respectively. The subsoil bulk density increased from $1.47Mg\;m^{-3}$ to $1.52Mg\;m^{-3}$ from 2011-2015. Excess ratio for soil physical standards increased from 16% to 22% in orchard, 56% to 62% in paddy, and decreased from 41% to 29% in upland. The overall soil physical quality had been ameliorated for upland, but degraded for paddy. Improved tillage practices and application of appropriate organic matter is necessary to enhance the quality of soils, especially in the paddy field.

• The Korean Journal of Ecology
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• v.23 no.5
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• pp.369-375
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• 2000

Although urban soils must be well understood in order to ensure their conservation and optimum use, these intensively managed and disturbed soils have not been extensively investigated up to now. Urban soils from forest, lawn, streetside, and bare ground and under pavement in Inchon had high bulk density as a result of widespread trampling-induced soil compaction. The various urban soils including forests showed lower water content and higher temperature as compared with rural forest soil. Chemically, soils from urban areas had an unusual neutral pH and low organic matter content. Total bacterial numbers in urban soils was only 5∼50% of that in the rural forest soil. An analysis of stepwise multiple regression revealed that soil organic matter was the most important predictor variable on total bacterial number. The dehydrogenase activity of most urban soils was not significantly different from that of rural forest soil, whereas the microbial activity of soils under pavement was lower. Our investigations show that inadequate organic matter of highly compacted soils has adversely affected the abundance of microorganisms involving nutrient cycling in urban soils.

• Korean Journal of Organic Agriculture
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• v.23 no.4
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• pp.767-779
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• 2015

soil microbial activities and diversities in a newly reclaimed soil. Soil chemical properties, population of microbe, microbial biomass, and properties of microbial community were investigated under 4 different treatment (animal manure compost+green manure, chemical fertilizer, and without fertilizer). The experiment was conducted for 3 years from 2012 to 2014. The most of chemical properties in the animal manure compost+green manure treatment were increased continually compare to chemical fertilizer and without fertilizer. The population of bacteria and fungi were higher in the animal manure compost+green manure treatment, however, there was no difference on actinomyces. Soil microbial biomass C content was higher in the animal manure compost+green manure treatment than in chemical fertilizer and without fertilizer. Biolog examination showed that catabolic diversities of bacterial communities were higher in the treatment of animal manure compost+green manure. It was showed that principle component analysis of the Biolog data differentiated the organic matter amended soils from NPK and control. These results indicated that application of animal manure compost+green manure had a beneficial effect on soil microbial properties.