• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.346-346
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• 2017

In Northern Laos, maize is cultivated in continuous cropping without fertilizer, fallowing nor any other soil conservation practice. It is expected that this inadequate management in maize cultivation will degrade soil and decrease yield. However, there is limited information about the change of soil condition and yield under continuous maize cultivation. We tried to evaluate the change of soil condition and yield under continuous maize cultivation in Northern Laos. Our study was conducted in farmer's flat and slope fields in Sainyabuli province where maize cultivation had been introduced earlier than the other provinces of Northern Laos. Our study was conducted in 21 fields in 2014, and in 19 fields in 2015. We analyzed grain yield and soil characteristic (total carbon (TC), total nitrogen (TN), available phosphorus (Av-P), exchangeable cation, pH, soil texture) at 3 places in each field. The 3 places were set at different elevation level (lower position, middle position, upper position) in slope fields. Further, the period of continuous maize cultivation and crop management practice were investigated. Then, by evaluating the relation between the period of continuous maize cultivation and yield and the soil characteristics, the effect of maize cultivation was estimated. Crop management practices were similar among the investigated fields. Maize was cultivated in rain season. Grain seed and cob were harvested on September or October, but shoot was left on the fields. No crop was cultivated during dry season. Fertilization and fallowing has never been conducted under continuous maize cultivation. On the other hand, the period of maize cultivation was different among the fields, and ranged from 2 years to 30 years. In the slope fields, as the period of continuous maize cultivation was longer, the contents of TC and TN were lower at all 3 positions, Av-P content was lower at the upper position, exchangeable potassium (Ex-K) content was lower at the middle and the upper positions. The other soil characteristics weren't related with the period of maize cultivation in the slope fields. In contrast, soil characteristics weren't related with the period of maize cultivation in the flat fields. Yield was lower as the period of maize cultivation was longer at the upper position of the slope fields. At middle position of slope fields, yield tended to be low with increase of the period of maize cultivation. In contrast, yield wasn't related with the period of continuous maize cultivation in flat fields. From the results about crop management, it was presumed that the period of maize cultivation was one of the main factors causing the difference of yield and soil characteristics among the fields. Therefore, from the result of yield and soil condition, it was considered that the continuous maize cultivation decreased soil productivity in the slope fields with decline of TC, TN, Av-P, Ex-K and yield at upper position of slope fields, and decline of TC and TN in the other positions in Sainyabuli province.

• Journal of Ginseng Research
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• 제19권2호
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• pp.175-180
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• 1995

The disease development of root-rot [pathogen:Cylindrocarpon destruction (Zinssm.) Scholten] occurred in 2-year old ginseng (Panax ginseng C.A. Meyer) was investigated in the continuous (the first cultivation: 1978∼1982, 2nd cultivation: 1990∼1993 and abolished in 1993 due to replanting problem) and replanted cultivation (period of cultivation: 1980∼1984). In the continuous cultivation, incidences of root-rot were 0.7% on May 3, 48.6% on May 24, and 95.8% on June 14, respectively. In the replanted cultivation, no symptom was observed on May 3 and disease incidence was generally lower compared with the continuous cultivation. On the aerial part of the ginseng infected by C. desiccates, the end and/or margin of leaves were changed to dark reddish color that appeared for behind the root-rot symptom. In this field, the longitudinal growth of lateral root was more inhibited than in the case of the replanted cultivation by C. destmctans. The inhibition rate of rootlet growth was 37.3% in the continuous cultivation as compared with that of replanted cultivation at June 14. Though lesions of root-rot were formed all over the roots, 61.2% of the lesions was positioned within 6 cm under the rhizome. Key words Panax ginseng, Cylindrocarpon destmtan, root-rot of ginseng, replanting problem of ginseng.

• 한국토양비료학회지
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• 제21권1호
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• pp.49-54
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• 1988

고추의 연작장해(連作障害) 요인(要因)을 분석(分析)하여 연작지토양개량(連作地土壤改良)을 위(爲)한 기초자료(基礎資料)를 얻고자 1985~1986년(年) 2개년(個年) 동안 전북(全北) 임실군(任實郡) 관촌(館村)의 고추 주산단지(主産團地)에서 시험(試驗)을 수행(遂行)하였던바 그 결과(結果)를 요약(要約)하면 다음과 같다. 1. 조사지역(調査地域)의 연작면적비율(連作面積比率)은 2년연작(年連作)이 12.7%였으며 3년연작(年連作)이 6.8%, 4년이상연작(年以上連作)은 48.9% 였다. 2. 연작지(連作地)의 토양이화학성(土壤理化學性) 특성(特性)은 토양경도(土壤硬度)가 높고 토양삼상중(土壤三相中) 기상(氣相)의 비(比)가 낮았으며 유효인산(有效燐酸)은 508 ppm, 치환성가리(置換性加里) 0.86me/100g로 적정치(適正値)보다 월등(越等)히 높았다. 3. 토양미생물(土壤微生物)의 균류(菌類)에 대(對)한 세균수(細菌數)(B/F비(比))와 방선균수(放線菌數)(A/F비(比))는 연작연한(連作年限)이 많을 수록 낮아지는 경향(傾向)이었다. 4. 토양선충밀도(土壤線蟲密度)는 1년재배지(年栽培地) 359, 2년연작지(年連作地) 391, 3년연작지(年連作地) 495, 4년이상연작지(年以上連作地)가 524마리/100g이였으며 경사(傾斜)가 심(甚)하고 배수(排水)가 양호(良好)할수록 낮았다. 5. 역병발생(疫病發生)은 4년이상연작지(年以上連作地)의 이병주율(罹病株率)이 14.3%로 1년재배지(年栽培地)의 0.7%에 비(比)해 월등(越等)히 높았으며 경사(傾斜)가 완만할수록 탄저병(炭疽病)은 감소(減少)되고 역병(疫病)은 증가(增加)되는 경향(傾向)이였다.

• 한국약용작물학회지
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• 제28권3호
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• pp.209-220
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• 2020

Background: This study investigated the effects of soil properties on the soil fungal community in first and continuous cultivation areas of Cnidium officinale Makino. Methods and Results: The soil fungal community was analyzed for relative abundance and principal coordinate analysis (PCoA) was conducted using Illumina MiSeq sequencing. The correlation between the soil chemical properties and the soil fungal community was assessed with distance-based linear models (DISTLM). The soil fungal community showed distinct clusters consisting in the continuous cultivation area of C. officinale Makino. PCoA and DISTLM indicated that soil pH, calcium, and available P₂O₅ significantly affected the soil fungal community in the cultivation area of C. officinale Makino. In addition, considering 5 different pathogenic fungi the relative abundance of Fusarium in the continuous cultivation area was significantly higher compared to that in the first cultivation area of C. officinale Makino. Conclusions: This study is important because it has determinined the effects of soil properties on the soil fungal community in both first and continuous cultivation areas of C. officinale Makino. Moreover, these results will be helpful to investigate the cause of continuous cropping obstacle in C. officinale Makino by examining the changes of soil fungal community.

• 한국토양비료학회지
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• 제25권3호
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• pp.270-274
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• 1992

땅콩의 연작장해요인(連作障害要因)을 구명(究明)하기 위한 기초자료(基礎資料)를 얻고자 전북(全北) 고폐의 땅콩 주산단지(主産團地)에서 시험(試驗)을 수행(遂行)하였던 바 그 결과(結果)를 요약(要約)하면 다음과 같다. 1. 연작지(連作地)의 토양이화학적특성(土壤理化學的特性)은 토양경도(土壤硬度)가 높고 토양삼상중(土壤三相中) 기상(氣相)의 비(比)가 낮았으며 유효인산(有效燐酸)과 치환성가리(置換性加里)는 이상치(理想値)보다 높았다. 2. 토양미생물(土壤微生物)의 사상균(絲狀菌)(F)에 대(對)한 세균(細菌)(B)수(數)인 B/F비(比)와 방선균(放線菌)(A)수(數)인 A/F비(比)는 연작년수(連作年數)가 많을수록 낮아지는 경향(傾向)이었다. 3. 토양선충밀도(土壤線蟲密度)는 1년재배지(年栽培地) 298, 2년재배지(年栽培地) 498, 3년이상재배지(年以上栽培地)가 586마리/100g로 동일작물(同一作物)을 연작(連作)할수록 선충(線蟲) 밀도(密度)는 높았다. 4. 주요병발생(主要病發生)은 흑분병(黑粉病)과 청고병(靑枯病)으로 생육후기(生育後期)와 연작년수(連作年數)가 길수록 병발생률(病發生率)이 심(甚)하였다.

• Korean Chemical Engineering Research
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• 제56권1호
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• pp.73-78
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• 2018

본 연구는 혼합영양 배양 조건에서 acetate의 주입이 Anabena azollae의 성장에 미치는 영향을 파악하기 위해 수행되었다. 4가지 종류의 acetate 중 ethyle acetate가 Anabena azollae의 성장에 가장 효과적이라고 밝혀졌으며, 주입한 ethyle acetate의 농도가 증가할수록 성장속도는 증가하는 것을 확인하였다. 40 mM의 ethyl acetate의 경우 비성장속도는 $0.979day^{-1}$, 최대바이오매스 생산성은 $0.293g\;L^{-1}\;d^{-1}$로 본 연구에서 배양속도가 가장 빠른 것으로 판명되었다. Acetic acid와 butyl acetate의 경우 Anabena azollae 성장을 방해하는 것으로 나타났다. Aetration의 경우 0.54 vvm에서 성장속도가 가장 빨랐다. 반연속배양에서는 aeration 실험이 끝난 후 연속하여 ethyle acetate 주입을 하여 배양을 하였다. 회분식실험에 비해 반연속배양에서의 비성장속도와 최대바이오매스 생산성은 모두 감소하였지만 최대 농도는 5.91 g/L로 가장 큰 값을 나타내었다.

• 대한환경공학회지
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• 제34권8호
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• pp.523-527
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• 2012

본 연구는 담수미세조류의 일종인 클로렐라를 적색 발광다이오드를 이용하여 효율적으로 반연속 배양하기 위한 조건을 찾기 위해 수행되었다. 클로렐라 배양에 가장 효율적인 적색 LED를 사용하여 반연속배양을 실시하였으며, 배양 중 인과 질소가 급격히 감소하였으며 이는 클로렐라의 성장과 반비례의 관계를 보여 주었다. 효율적인 반연속 배양을 위해 인과 질소의 농도를 증가시킨 배지를 사용하여 배지교체 주기를 연장시켜 배양 효율성을 높였다. 배지교체 시 클로렐라의 셀 농도는 지속적으로 증가하였으나, 셀 크기는 감소하였다. 셀 농도와 셀 크기를 고려할 때 배양 전과정을 통해 생산되는 바이오매스의 양은 일정하게 유지되었다.

• Journal of Microbiology and Biotechnology
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• 제9권6호
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• pp.716-721
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• 1999

It has been known that continuous cultivation of hairy root is difficult to maintain for a long period of time compared to the microbial and callus cultures. Chemostat cultivation was successfully carried out in order to economically produce a plant-based colorant, betacyanin, from red beet hairy root for more than 85 days in a 14-1 fermentor. The result from the chemostat cultivation was compared to those of the batch and fed-batch cultivations of red beet hairy roots. It was shown that hairy root reached its steady state within 50 days of the cultivation, and then maintained for about 25-30 days in a wide range of dilution rates. Total betacyanin production from the continuous process was also calculated to be 2.65g at 0.28(l/d) of dilution rate, compared to 0.196g from fed-batch cultivation. It was found that betacyanin production was a partially growth related process, yielding 0.376 mg/g-fresh wt. cell and $1.89{\times}10^{-5}$ mg/g-fresh wt. cell/d, with 0.92 of correlation factor in a partial growth-product model. It was also shown that the cell growth required was relatively large for maintenance amount of energy at a low dilution rate. The growth of hairy root was inhibited by high light intensity in following a photo-inhibition model. The growth parameters were estimated to be 0.3(l/d), $10.56kcal/\textrm{m}^2/h$,{\;}and{\;}35.81kcal/\textrm{m}^2/h$ for the maximum specific growth rate, half saturation light intensity, and inhibition light intensity, respectively.

• 한국해양바이오학회지
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• 제10권2호
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• pp.73-82
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• 2018

Chlorella are source of valuable compounds as lipids, proteins, carbohydrates, bioactive compounds. To continuous obtain the high-value materials of Chlorella protothecoides, we performed continuous cultivation after applying milking techniques to C. protothecoides grown with culture for 7 days in optical panel bioreactor (OPBR) system. Fatty acid and lutein in extracts from pre- and post-milking of C. protothecoides were analyzed using gas chromatography and high performance liquid chromatography, respectively. C. protothecoides were rich in unsaturated fatty acids with a high content of oleic acid(C18:1), which is suitable as a biofuel feedstock. The fatty acid content in pre- and post-milking of C. protothecoides was decreased from 126.424mg/g d.w. to 119.341mg/g d.w, and the lutein content decreased from 0.258mg/g d.w. to 0.178mg/g d.w. The results of this study demonstrate the feasibility of milking C. protothecoides for production of lipids for biofuels production. It was confirmed that microalgae can continuously obtain lutein present in a trace amount through a continuous culture from milking.

• 대한약침학회지
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• 제10권2호통권23호
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• pp.67-71
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• 2007

Objectives : This experimental study was performed to investigate the continuous anti-bacterial potency of Tangpo-san on cultivation of Staphylococcus species(S. aureus, S. epidermidis)that induce eye disease. Methods : Minimal inhibitory concentration(MIC) was measured by dropping to 50 ${\mu}$l diluted Tangpo-san(100%, 10%, 1%, 0.1%) on S. aureus, S. epidermidis that were cultivated from 2 to 6 days. Anti-bacterial potency was measured by the size of inhibition zone with change of volume(20 ${\mu}$l,30 ${\mu}$l,40 ${\mu}$l,50 ${\mu}$l). Results : 1. Anti-bacterial potency of Tanpo-san on S. aureus was not appeared all samples. Anti-bacterial potency with change of volume was increased in propotion to increase volume, and the Anti-bacterial potency of 2 days was equal to 6 days. Anti-bacterial potency of Tangpo-san on S. aureus was appeared continuous. 2. Anti-bacterial potency of Tangpo-san on S. epidermidis was appeared in 100%, 10% on 2 and 6 days, and the Anti-bacterial potency of 6 days was decreased. In 2 days, Anti-bacterial potency was appeared 40 and 50u1, in 6 days, Anti-bacterial potency was appeared all samples. Anti-bacterial potency with change of volume was increased in propotion to increase volume and increased on 6 days, but bacteria was increased. Anti-bacterial potency of Tangpo-san on S. epidermidis wasn't appeared continuous. Conclusions : Anti-bacterial potency of Tangpo-san on cultivation of S. aureus showed continuous, but on cultivation of S. epidermidis was not showed continuous.