• Journal of Ecology and Environment
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• 제46권4호
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• pp.282-291
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• 2022

Background: The Arctic permafrost stores enormous amount of carbon (C), about one third of global C stocks. However, drastically increasing temperature in the Arctic makes the stable frozen C stock vulnerable to microbial decomposition. The released carbon dioxide from permafrost can cause accelerating C feedback to the atmosphere. Soil organic matter (SOM) composition would be the basic information to project the trajectory of C under rapidly changing climate. However, not many studies on SOM characterization have been done compared to quantification of SOM stocks. Thus, the purpose of our study is to determine soil properties and molecular compositions of SOM in four different Arctic regions. We collected soils in different soil layers from 1) Cambridge Bay, Canada, 2) Council, Alaska, USA, 3) Svalbard, Norway, and 4) Zackenberg, Greenland. The basic soil properties were measured, and the molecular composition of SOM was analyzed through pyrolysis-gas chromatography/mass spectrometry (py-GC/MS). Results: The Oi layer of soil in Council, Alaska showed the lowest soil pH and the highest electrical conductivity (EC) and SOM content. All soils in each site showed increasing pH and decreasing SOC and EC values with soil depth. Since the Council site was moist acidic tundra compared to other three dry tundra sites, soil properties were distinct from the others: high SOM and EC, and low pH. Through the py-GC/MS analysis, a total of 117 pyrolysis products were detected from 32 soil samples of four different Arctic soils. The first two-axis of the PCA explained 38% of sample variation. While short- and mid-hydrocarbons were associated with mineral layers, lignins and polysaccharides were linked to organic layers of Alaska and Cambridge Bay soil. Conclusions: We conclude that the py-GC/MS results separated soil samples mainly based on the origin of SOM (plants- or microbially-derived). This molecular characteristics of SOM can play a role of controlling SOM degradation to warming. Thus, it should be further investigated how the SOM molecular characteristics have impacts on SOM dynamics through additional laboratory incubation studies and microbial decomposition measurements in the field.

• 한국환경농학회지
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• 제22권3호
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• pp.177-184
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• 2003

Although clay can sorb significant amounts of inorganic contaminants from soils and wastewater, the hydration of exchangeable cations in clay minerals makes it hydrophilic at the clay mineral surfaces and interlayers. Thus, natural clays are often ineffective in complexing and stabilizing toxic organic contaminants in soils and groundwater environment. But, substituting these hydrated cations with cationic surfactant such as QAC(Quaternary ammonium Compound) can change the natural clay from hydrophilic to hydropobic. Furthermore functionalized organoclay can act as a powerful dual function sorbent for both toxic metals and organic compounds. It also can be used as landfill clay liners, slurry walls, nano-composite materials, petroleum tank farms, waste treatment, and filter systems. To use this modified clay minerals effectively, it is required to understand the fundamental chemistry of organoclay, synthetic procedures, its engineering application, bioavailability of sorbed ion-clay complex, and potential risk of organoclay. In this review, we investigate the use, application and historical background of the organoclay in remediation technology. The state-of-the-art of organoclay research is also discussed. Finally, we suggest some future implications of organoclay in environmental research.

• 한국토양비료학회지
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• 제47권3호
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• pp.205-212
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• 2014

Chronological changes of soil organic carbon (SOC) must be prepared by IPCC guidelines for national greenhouse gas inventories. IPCC suggested default reference SOC stocks for mineral soils and relative stock factors for different management activities where country own factors were not prepared. 3.4 million data were downloaded from agricultural soil information system and analyzed to get chronological changes of SOC for some counties and for land use in Korea. SOC content of orchard soil was higher than the other soils but chronological SOC changes of all land use had no tendency in differences with high standard deviation. SOC contents of counties depended on their own management activities and chronological SOC changes of districts also had no tendency in differences. Thus, Korea should survey the official records and relative stock factors on management activities such as land use, tillage and input of organic matter to calculate SOC stocks correctly. Otherwise, Korea should establish a model for predicting SOC by analyzing selected representative fields and by calculating SOC differences from comparing management activities of lands with those of representative fields.

• 한국토양비료학회지
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• 제17권4호
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• pp.330-336
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• 1984

우리나라 토양(土壤)의 대표적(代表的)인 물리화학적(物理化學的) 성질(性質)을 구명(究明)하여 토지생산력(土地生産力) 향상(向上)을 위(爲)한 토양(土壤) 개량(改良)에 필요(必要)한 자료(資料)를 제공(提供)하고자 정밀(精密) 토양조사(土壤調査) 결과(結果) 밝혀진 제주도(濟州道) 토양(土壤)을 제외(除外)한 315개(個) 토양통(土壤統)에 대(對)한 토성(土性), 수분특성(水分特性), 유기물함량등(有機物含量等) 14개(個) 물리화학성(物理化學性)을 수집(蒐集)하여 토지이용(土地利用), 배수등급(排水等級), 토양유형별(土壤類型別)로 단순(單純) 평균치(平均値)와 분포면적(分布面積)을 고려(考慮)한 가중(加重) 평균치(平均値)를 전산처리(電算處理)한 결과(結果)는 다음과 같다. 1. 우리나라 전체(全體) 토양통(土壤統)의 단순(單純) 평균치(平均値)는 점토(粘土) 20.0%, 유기물(有機物) 2.03%, 양(陽)이온 치환용량(置換容量) 10.3me/100g이었으며 분포면적(分布面積) 가중평균치(加重平均値)는 점토(粘土) 18.0%, 유기물(有機物) 1.85%, 양(陽)이온 치환용량(置換容量) 8.6me/100g 으로 밝혀졌다. 2. 토지이용(土地利用別)로 점토함량(粘土含量)을 보면 논이 19.7%에 비(比)하여 밭과 임지(林地)는 각각(各各) 17.9%, 16.7%로 낮은 편이고 유기물함량(有機物含量)은 논이 2.0%로서 밭과 임지(林地)의 1.8%보다 높았으며 양(陽)이온 치환용량(置換容量)도 논이 9.1me/100g으로 가장 높고 다음으로 임지(林地)는 8.6me/100g, 밭은 8.1me/100g의 순(順)이다. 3. 배수등급별(排水等級別) 가중평균치(加重平均値)를 보면 배수(排水) 약간(若干) 양호(良好)한 경우 점토함량(粘土含量) 18.9%, 유기물(有機物) 1.7%, 양(陽)이온 치환용량(置換容量) 8.4me/100g이고 약간(若干) 불량(不良)인 경우는 점토함량(粘土含量) 21.3%, 유기물(有機物) 2.2%, 양(陽)이온 치환용량(置換容量) 9.5me/100g 이었고 불량(不良)인 경우는 점토함량(粘土含量) 15.1%, 유기물(有機物) 1.8%로서 양(陽)이온 치환용량(置換容量)만이 9.9me/100g으로 제일 높았다. 4. 논, 밭토양(土壤)에 대(對)한 유형별(類型別) 점토함량(粘土含量), pH, 유기물(有機物), 양(陽)이온 치환용량(置換容量), 염기포화도등(鹽基飽和度等)이 밝혀졌다.

• 아시안잔디학회지
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• 제10권3호
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• pp.195-211
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• 1996

Dictyostelids cellular slime molds were isolated from the soils of Gokneung and Anyang streamside in Korea. The fifteen species including two undescrihed species were identified. These were as follows ; Dictyostelium macrocephalurn D. sphaerocephalum, D. aureum var. aureum, D.mucoroides, D. minutum, Polyspondyium pallidum. D. giganteum, P. violaceum. D. purpureum. D.brefeldianum, D. flavidum, D. mucoroides var. storoniferum, D. septentrionalis, D. aureum var. luteolum,D. aureo-stipes var. aureo-stipes. D. macrocephalum was the dominant species. and D. sphaerocephalum. D. aureum var. avreum were relatively common. D. mucoroides var. storoniferum, D. septentrionalis were the undescrihed species in Korea. In the soils of streamside, dominant species was shifted by D. macrosephalum, D. sphaerocephalum. which were rare in the forest soils. The total clones per gram of streamside soils were greater than that of forest soils, whereas the number of species in streamside was smaller than the in forest soils. As a result, the ratio of the number of clones to species was very high in the soils of streamside, Environmental factors of soil pH, water content, organic content, total nitrogen and total phosphorus made a effect differently on the cellular slime molds community. Key words: Cellular slime molds, D. macrocephalum, D. sphaerocephalum, Shift of dominant species, Environmental factors.

• 한국토양비료학회지
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• 제47권6호
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• pp.500-505
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• 2014

In recent years, organic ginseng cultivation has increased because customers prefer organic ginseng products due to the morphological quality as well as the safety such as the residuals of chemically-synthesized pesticides. Therefore, some of paddy and upland fields were converted into organic ginseng fields. Soil chemical properties, soil microflora, and soil-inhabiting animals were investigated in paddy-converted and upland organic ginseng fields in Sangju city, Korea. There was few difference in the soil chemical properties, and the soil nutrient concentrations, such as nitrate-N, Av. $P_2O_5$ between the two field types, and exchangeable cations such as K and Ca were within the ranges which are recommended by the standard ginseng-farming manual. Changes in microflora were also assessed by analyzing phospholipid fatty acid composition. Overall, indicators of microbial groups were greater in the upland field than in the paddy-converted soil, but they were not significantly different. In addition, there was no significant change in the abundance of nematodes, collembolans, and mites between the two field types probably because of the high variation within the field types. In this study, it was suggested that soil chemical and biological properties for organic ginseng cultivation were greatly influenced by the variation of topography and soil management practices rather than field types. Further study may be needed to investigate the influence of these factors on soil chemical and biological properties in organic ginseng soils.

• 한국토양비료학회지
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• 제48권6호
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• pp.648-657
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• 2015

Soil organic matter (SOM) plays an important role in the continuous production and environmental conservation in arable soils. In particular, the decomposition of organic matter in soil might promote soil organic matter and fertility due to the mineralization of N. In this study, to evaluate the effect of organic matter amendment on the C mineralization and N dynamic, $CO_2-C$ flux, extractable N and $N_2O$ emission were determined using closed chamber for 4 weeks at 10, 15, $20^{\circ}C$ of incubation temperature after the mixture of $2Mgha^{-1}$ rice straw compost and rye in sandy loam and clay loam. Regardless of soil texture, decomposition rates of rice straw compost and rye at $10{\sim}20^{\circ}C$ of incubation temperature ranged from 0.9 to 3.8% and 8.8 to 20.3%, respectively. Rye application in soil increased $NH_4-N$ and $NO_3-N$ content as well as the $N_2O$ emission compared to the rice straw compost. After incubation for 4 weeks, total C content in two soils was higher in rice straw compost than in rye application. In conclusion, application of rice straw compost and rye to soil was able to improve the soil organic matter and fertility. However, organic matter including the recalcitrant compounds like rice straw compost would be effective on the management of soil organic matter and the reduction of greenhouse gases in soil.

• Applied Biological Chemistry
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• 제21권2호
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• pp.71-80
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• 1978

불란서(佛蘭西)의 수종(數種) 토양중(土壤中)에서 3,4-DCA 및 TCAB의 변화과정을 구명하기 위하여 환표식(環標識)된 $^{14}C-3,4-DCA$ 및 $^{14}C-TCAB$를 사용하여 실험을 행(行)한 바 다음의 결과(結果)를 얻었다. (1) $^{14}C-3,4-DCA$가 $^{14}CO_2$로 분해(分解)되는 속도(速度)는 배양초기(培養初期)에는 비교적(比較的) 빠르고 후기(後期)에는 완만하다. 배양 6개월 후(後)에 alkaline soil(pH=7.9)에서 dose 1(1.5 ppm)에서 최고(最高) 6.5%, dose 2(94 ppm)에서 최하(最下) 1.92%의 분해율(分解率)을 보였다. organic acid soil(pH=5.5)의 경우 dose 1에서 4.91%, dose 2에서 4.24%가 분해(分解)되었으며 양자간(兩者間)에는 대차(大差)가 없었다. (2) Dose 1로 3,4-DCA를 6개월동안 배양할 때 organic acid soil에서는 47.70%, Alkaline soil에서는 29.49%가 토양에 결합되었다. 한편 dose 2의 경우 organic acid soil에서는 38.40%, alkaline soil에서는 20.30%가 결합(結合)되었다. (3) 토양중(土壤中)에서 3,4-DCA로부터 생성(生成)되는 TC-AB의 양(量)은 토양(土壤)의 종류(種類)보다는 3,4-DCA의 사용농도(使用濃度)에 의존(依存)하는것 같다. dose 2에서 생성(生成)된 TCAB의 양(量)은 organic acid soil에서는 추출액(抽出液)의 총방사능(總放射能)의 50%, alkaline soil에서는 30%에 해당하며 이것은 토양시료(土壤試料)에 첨가한 최초(最初)의 방사능(放射能)의 1.8%와 1.4%에 각각(各各) 해당된다. 반면 dose 1에서는 추출액(抽出液)의 총방사능(總放射能)에 비(比)하여 두 토양(土壤) 공(共)히 $2{\sim}3%$를 넘지 못하며 최초(最初)의 총방사능(總放射能)의 $0.05{\sim}0.1%$를 초과(超過)하지 못한다. (4) $^{14}C-TCAB$가 $^{14}CO_2$로 분해(分解)되는 속도(速度)는 매우 느리며 배양 6개월후에 4종(四種)의 토양(土壤)에서 모두 $0.05%{\sim}0.20%$의 분해율(分解率)을 보였고 배양 3개월후에 뚜렷한 분해산물(分解産物)을 검출(檢出)할 수 없었으며 대부분(大部分) 미분해(未分解)된 상태로 존재(存在)하였다. (5) Alkaline soil에서 다른 토양에서 보다 훨씬 많은 양(量)의 $^{14}C-TCAB$가 토양중(土壤中)에 흡착(吸着)된 것으로 보아 Alkali토양 조건하에서 $trans-TCAB{\rightarrow}cis-TCAB$의 전환(轉換)이 일어나 이 흡착성이 더 강한 cis 이성체(異性體)가 토양중(土壤中)에 많이 흡착(吸着)된 것으로 생각(生覺)된다.

• 한국토양비료학회지
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• 제1권1호
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• pp.129-136
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• 1968

우리나라 답토양(畓土壤)의 대부분(大部分)을 차지하는 Low Humic Gley Soil의 이화학적(理化學的) 성질(性質) 및 광물학적(鑛物學的) 성질(性質)을 구명(究明)하는 한편 답토양(畓土壤)의 하층(下層)에서 발견(發見)되는 Iron Concretion의 성상(性狀) 및 생성조건(生成條件)을 고찰(考察)해 보고자 본시험(本試驗)을 실시(實施) 하였던바 김제지방(金堤地方)의 Low Humic Gley Soil은 약(弱)하게 발달(發達)된 토양(土壤)으로써 25~100cm 사이에서 흑색(黑色) 유기물층(有機物層)이 나타나고 있으며 염기포화도(鹽基飽和度)가 70%이상(以上)으로 높은 편이며 Coarse Clay의 C.E.C는 12-15me/100gm, Fine Clay의 CEC는 30me/100gm 전후(前後)이다. 광물학적(鑛物學的) 조성(組成)은 우리나라의 대부분(大部分)의 다른 토양(土壤)과 같이 Kaolinite가 Dominant하고 기타(其他) Mica 또는 Illite, Vermiculite, Qurtz, Chlorite, Montmorillonite 등(等)이 소량(小量) 포함(包含)되며 $10{\sim}14A^{\circ}$에서는 Ch-Mi, Ch-Mo등(等)의 Stratification도 일부(一部) 나타나고 있다. Iron Concertion은 비교적(比較的) 순수(純粹)한 $FeCO_3$로 배수(排水)가 불량(不良)한 환원층내(還元層內)에서 $Fe^{\sharp}$의 농도(濃度)가 높아지면 유기물(有機物)의 미생물(微生物)에 의(依)한 분해(分解)로서 생성(生成)된 $CO_2$와 작용(作用)하여 $FeCO_3$를 형성(形成)하는 것으로 본다. 이와 같은 결과(結果)는 여러 사람(5)(6)에 의하여도 증명된 바 있다.

• 한국토양비료학회지
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• 제45권2호
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• pp.143-148
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• 2012

경남지역 논토양의 양분관리를 위한 기초자료를 제공하기 위해 260 지점의 화학성분 변동을 1999년부터 2011년까지 4년 주기로 분석하였다. 논토양 pH, 유기물 함량, 유효인산 함량, 유효규산 함량, 치환성 칼슘 및 마그네슘 함량은 1999년에 비해 2011년에 유의적으로 증가하였다. 유기물 함량의 초과비율은 1999년 40.0%, 2003년 30.4%, 2007년 48.5%, 2011년 50.8%로 증가하였다. 유효인산 함량의 초과비율은 1999년 55.0%, 2003년 57.7%, 2007년 52.7%, 2011년 63.5%로 2배 이상 과잉 집적되었다. 유기물 함량은 홍적대지에서 가장 높았고 유효인산 함량은 산록경사지에서 가장 높았다. 논토양의 통계분석과 주성분 분석을 통하여 경남지역 논토양의 유효인산 함량은 지형별 화학특성을 구별할 수 있는 중요인자로 판단되었다.