• Fisheries and Aquatic Sciences
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• 제11권1호
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• pp.15-22
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• 2008

Excessive growth of phytoplankton is a common and severe problem in intensively farmed pangasiid catfish (Pangasius hypophthalmus) culture ponds. It can lead to cyanobacterial blooms, reduced fish growth, bad-tasting fish flesh, and lower market demand. To investigate how to manage undesirable phytoplankton growth, we evaluated three stocking strategies in nine rural fishponds (0.020-0.022 ha) owned by various farmers: a pangasiid catfish mono culture (treatment 1, $T_1$), and pangasiid catfish-silver carp (Hypophthalmichthys molitrix) polycultures at two stocking ratios of 1:1 (treatment 2, $T_2$) and 2:1 (treatment 3, $T_3$). The total density of all ponds was approximately 30,000 fishes/ha. Monoculture ($T_1$) resulted in significantly higher (p < 0.05) nutrient levels (nitrate and phosphate) in ponds than did polyculture ($T_2$ and $T_3$). Nutrient loads increased with culture time, resulting in increased growth of phytoplankton, including Cyanophyceae (9 genera), Chlorophyceae (15 genera), Bacillariophyceae (8 genera), and Euglenophyceae (3 genera). The introduction of silver carp as a co-species helped to regulate phytoplankton growth and to improve the water quality of pangasiid catfish culture ponds.

• Journal of Forest and Environmental Science
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• 제30권4호
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• pp.315-321
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• 2014

Forest timber production potential of any site is oftentimes measured quantitatively by site index, which is defined as dominant height of a particular stand at a specified age. A site index was developed for estimating site quality of monoculture Pinus caribaea plantations in southwestern Nigeria using a base age of 25 years. Dominant height data were collected from 60 Temporary Sample Plots (TSPs) of $20{\times}20m$ in plantations of 15 to 37 years. Linear and non-linear models as been widely applied in quantitative forest measurements were fitted to dominant height-age data and the best site index equation is : $SI=Exp^{(InHd-23.495(A^{-2}-0.04)}$. The site index curves constructed for the three sites (Omo Forest Reserve - OFR (J4), Oluwa Forest Reserve - OLFR and Shasha Forest Reserve - SFR) across the southwestern Nigeria using the chosen equation revealed that a 15 year old Pinus caribaea in the study area attained average dominant heights of 25, 22 and 21 m in OFR (J4), OLFR and SFR respectively. The site index equation and curves proffer veritable insight into better silvicultural options and management practices for the future plantations suitable sites.

• Asian-Australasian Journal of Animal Sciences
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• 제26권10호
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• pp.1416-1423
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• 2013

The metabolomic profile of the anaerobic fungus Piromyces sp. F1, isolated from the rumen of goats, and how this is affected by the presence of naturally associated methanogens, was analyzed by nuclear magnetic resonance spectroscopy. The major metabolites in the fungal monoculture were formate, lactate, ethanol, acetate, succinate, sugars/amino acids and ${\alpha}$-ketoglutarate, whereas the co-cultures of anaerobic fungi and associated methanogens produced citrate. This is the first report of citrate as a major metabolite of anaerobic fungi. Univariate analysis showed that the mean values of formate, lactate, ethanol, citrate, succinate and acetate in co-cultures were significantly higher than those in the fungal monoculture, while the mean values of glucose and ${\alpha}$-ketoglutarate were significantly reduced in co-cultures. Unsupervised principal components analysis revealed separation of metabolite profiles of the fungal mono-culture and co-cultures. In conclusion, the novel finding of citrate as one of the major metabolites of anaerobic fungi associated with methanogens may suggest a new yet to be identified pathway exists in co-culture. Anaerobic fungal metabolism was shifted by associated methanogens, indicating that anaerobic fungi are important providers of substrates for methanogens in the rumen and thus play a key role in ruminal methanogenesis.

• 한국미생물·생명공학회지
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• 제22권6호
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• pp.685-691
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• 1994

The biodegradation of aromatic compounds by mixed and monoculture was investigated in an artificial wastewater containing 500 mg/l of benzene(B), phenol(P), and toluene(T) in various combinations. None of three strains utilized P-xylene(X) as a carbon source, but they grew well on p-xylene in mixtures with benzene and toluene. In the mixed culture on mixed substrate, the length of lag phase was different depending on the nature of mixture. Cell growths of Flavobac- terium sp. BEN2 and Acinetobacter sp. GEM63 were inhibited in the presence of a 500 mg/l of phenol. When the mixed culture of three strains was cultured in a bench-scale reactor containing artificial wastewater, each of benzene, phenol, and toluene was not detected at 30 hrs, 50 hrs, and 12 hrs after incubation in the treatment. The removal rates of COD$_{t}$(total COD) and COD$_{s}$,(soluble COD) of upper phase after centrifugation during early 50 hrs were ca. 80% and ca. 93.8%, respectively.

• 한국초지조사료학회지
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• 제8권3호
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• pp.158-164
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• 1988

The growth characteristics and yield per unit area of two cropping systems, corn monoculture and 'wrnsoybean intercropping, were compared and the obtained results were as follows; 1.The two cultivation systems were not significantly different in leaf length, leaf width and length of internode at harvesting time. 2.The weight of stalk and the leaves of a plant were decreased with maturity, while the weight of ear was markedly increased. The patterns of relative ratio of each components were essentialy same in each cultivation systems. In corn monoculture, the percentages of stalk, leaf, and ear at final harvesting stage were 22.9, 13.7, and 63.4 and in corn-soybean intercropping, they were 21.8, 10.9, and 67.3 respectively. 3.Dry matter yield per unit area (kg/lOa) of intercropped corn at yellow stage was similar to that of monocultured corn (1, 483 kg/ 10a vs 1, 509 kg/ 10a). At ripe stage, however, the dry matter yield of intercropped plant was more than that of monocultured (1, 679 vs 1, 660 kg/ 10a). 4.The same pattern was observed in organic matter yield.

• Journal of Microbiology and Biotechnology
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• 제33권6호
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• pp.760-770
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• 2023

Continuous cropping obstacles have become a serious factor restricting sustainable development in modern agriculture, while companion planting is one of the most common and effective methods for solving this problem. Here, we monitored the effects of companion planting on soil fertility and the microbial community distribution pattern in pepper monoculture and companion plantings. Soil microbial communities were analyzed using high-throughput sequencing technology. Companion plants included garlic (T1), oat (T2), cabbage (T3), celery (T4), and white clover (T5). The results showed that compared with the monoculture system, companion planting significantly increased the activities of soil urease (except for T5) and sucrase, but decreased catalase activity. In addition, T2 significantly improved microbial diversity (Shannon index) while T1 resulted in a decrease of bacterial OTUs and an increase of fungal OTUs. Companion planting also significantly changed soil microbial community structures and compositions. Correlation analysis showed that soil enzyme activities were closely correlated with bacterial and fungal community structures. Moreover, the companion system weakened the complexity of microbial networks. These findings indicated that companion plants can provide nutrition to microbes and weaken the competition among them, which offers a theoretical basis and data for further research into methods for reducing continuous cropping obstacles in agriculture.

• 한국초지조사료학회지
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• 제26권4호
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• pp.207-214
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• 2006

본 시험은 2002년 9월부터 2004년 12월까지 충남대학교 농업생명과학대학 내 부속 초지시험포장에서 수행하였다. 공시초종은 청예웅 호밀(Koolgrazer)과 헤어리베치(Common)를 공시하여 주구로 호밀 단파, 호밀 80%+헤어리베치 20% 혼파, 호밀 60%+헤어리베치 40%혼파 및 헤어리베치 단파 등의 4 파종유형과 세구로 수잉기, 출수기, 개화기 및 유숙기 등의 4 수확시기를 두어 분할구배치법 3반복으로 시험하였으며, 얻어진 결과는 다음과 같다. 2년 평f ha당 건물수량은 파종유형과 수확시기에 따라 차이를 보여, 호밀 단파구(9,776kg)가 호밀 80%+헤어리베치 20% 혼파구(9,045kg)나 호밀 60%+헤어리베치 40% 혼파구(8,272kg) 및 헤어리베치 단파구(5,424kg)에 비하여 높은 결과를 나타내었고, 모든 처리구에서 수확시기가 진행됨에 따라 유의적으로 증가되었다(p<0.01). 화학적 성분도 파종유형과 수확시기에 따라 차이를 보여, CP 함량과 DMD는 헤어리베치 단파구에서 높았던 반면에 섬유소물질의 함량은 가장 낮았으나, 호밀 단파구에서는 상반되는 결과를 보였다(p<0.01). 조단백질수량(CPDM)과 가소화건물(DDM)수량은 호밀 80%+헤어리베치 20% 혼파하여 개화기${\sim}$유숙기에 수확하는 것이 가장 높았다.(p<0.01). 이상의 결과로 보아, 호밀이나 혜어리베치의 단파 이용보다는 호밀에 헤어리베치를 20% 정도 혼파하여 개화기${\sim}$유숙기에 수확하는 것이 단위 면적당 수량과 사료가치를 높일 수 있는 한가지 방법이라 하겠다.

• 한국토양비료학회지
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• 제24권1호
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• pp.22-27
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• 1991

답이작(畓裏作) 형태별(形態別)로 토양환경(土壤環境) 및 후작(後作)벼의 생산성(生産性) 변화(變化)를 구명(究明)하기 위하여 하성충적지인 미사질양토(微砂質壤土)에서 수도단작(水稻單作) 관행(慣行)으로 풋마늘-수도(水稻), 청예호밀-수도(水稻) 및 알타리무우-수도(水稻) 작부(作付)를 대상(對象)으로 포장시험(圃場試驗)하였다. 1. 토양(土壤)의 물리성(物理性)은 전작물(前作物) 수확후(收穫後) 작물별(作物別) 차이(差異)가 있었으며 이들의 잔류효과는 후작(後作)벼 이앙후(移秧後) 60~70일(日) 정도(程度)까지 유지(維持)되었다. 2. 전작물별(前作物別) 통기성(通氣性)은 청예호일, 풋마늘, 알타리무우 순(順)으로 컸으며 후작(後作)벼 재배시(裁培時) 감수심(減水深) 변화(變化)도 이와 유사(類似)한 경향(傾向)이었다. 3. 표토(表土)의 화학적(化學的)은 작부별(作付別) 시비량(施肥量)에 따라 달라졌고 전작물별(前作物別) 시비량(施肥量) 차이(差異)는 후작(後作)벼 수확기(收穫期)까지도 영향(影響)을 미쳤다. 연간(年間) 3요소(要素) 시비량(施肥量)과 흡수량비(吸收量比)로 볼때 청예호밀-수도(水稻), 알타리무우-수도(水稻), 수도단작(水稻單作), 풋마늘-수도(水稻) 작부(作付) 순(順)으로 효율적(效率的)이었으며 이를 감안(勘案) 후작(後作)벼의 시비량(施肥量) 조절(調節)이 요망(要望)되었다. 4. 후작(後作)벼 뿌리분포(分布)는 청예호밀 재배지(栽培地) 심토(深士)까지 고루 분포(分布)되었으며 표토(表土)에 양분잔존량(養分殘存量)이 많은 풋마늘, 알타리무우 후작(後作)벼 뿌리는 표토(表土)의 분포률율(分布率)이 높은 경향(傾向)이었다. 5. 전작물별(前作物別) 후작(後作)벼 수량(收量)은 풋마늘, 알타리무우, 수도단작(水稻單作), 청예호밀 순(順)이었다.

• 한국유기농업학회지
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• 제26권4호
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• pp.719-729
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• 2018

국내 유기농 밭 토양은 가축분퇴비, 유기질비료 등의 지속적인 투입에 의해 인산을 포함한 다량 양분이 축적되고 있다. 친환경 토양관리를 위하여 가축분퇴비나 유기질비료의 대안으로 보리(B)와 헤어리베치(H)의 혼파를 활용하고자 한다. 보리와 헤어리베치의 혼파가 녹비작물의 수량 및 양분 생산성에 미치는 효과를 평가하기 위하여, 가축분퇴비 연용으로 토양 양분이 축적된 유기농 밭 토양에 보리와 헤어리베치를 2016년 11월에 기준 파종량(B 160 kg/ha ; H 90 kg/ha) 대비 B 66%와 H 33%, B 33%와 H 66% 비율로 혼파 재배하였다. 수확기에 녹비작물 수량, 양분생산성을 분석하여 혼파 효과를 평가한 결과는 아래와 같다. 보리와 헤어리베치를 혼파 할 경우 녹비작물 수량이 헤어리베치 단파 보다 78~132% 증가되어, 혼파시 수량증대 효과가 있었다. 질소 생산성도 혼파에서 보리 단파보다 43~44% 증가, 인산 생산성도 헤어리베치 단파보다 200% 이상 증가되어 혼파의 양분생산성 증대 효과를 확인하였다. 본 연구 결과 보리와 헤어리베치의 혼파재배는 녹비작물의 수량 및 질소와 인생산성 증대에 효과적이라는 결과를 얻었으며, 2가지 측면을 모두 고려할 때, 기준 파종량 대비 보리 66%와 헤어리베치 33%를 혼파하여 파종한 처리(B66H33)가 가장 비료로써의 가치가 높아 양분이 축적된 유기농경지에서 활용할 수 있을 것으로 판단된다.

• 한국환경농학회지
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• 제38권4호
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• pp.219-224
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• 2019

BACKGROUND: Soil bacteria play important roles in organic matter decomposition and nutrient cycling during the non-growing season. The purpose of this study was to investigate the effects of soil management and chemical properties on the utilization of carbon sources by soil bacteria in paddy fields. METHODS AND RESULTS: The Biolog EcoPlate was used for analyzing community-level carbon substrate utilization profiles of soil bacteria. Soils were collected from the following three types of areas: plain, interface and mountain areas, which were tested to investigate the topology effect. The results of canonical correspondence analysis and Kendall rank correlation analysis showed that soil C/N ratio and NH₄⁺ influenced utilization of carbon sources by bacteria. The utilization of carbohydrates and complex carbon sources were positively correlated with NH₄⁺ concentration. Cultivated paddy fields were compared with adjacent abandoned fields to investigate the impact of cultivation cessation. The level of utilization of putrescine was lower in abandoned fields than in cultivated fields. Monoculture fields were compared with double cropping fields cultivated with barley to investigate the impact of winter crop cultivation. Cropping system altered bacterial use of carbon sources, as reflected by the enhanced utilization of 2-hydroxy benzoic acid under monoculture conditions. CONCLUSION: These results show that soil use intensity and topological characteristics have a minimal impact on soil bacterial functioning in relation to carbon substrate utilization. Moreover, soil chemical properties were found to be important factors determining the physiological profile of the soil bacterial community in paddy fields.