• Mycobiology
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• 제45권3호
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• pp.204-208
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• 2017

Nosema ceranae is an obligate intracellular fungal parasite that causes mortality in honey bees and enhances the susceptibility of honey bees to other pathogens. Efficient purification of Nosema spores from the midgut of infected honey bees is very important because Nosema is non-culturable and only seasonably available. To achieve a higher yield of spores from honey bees, in this study, we considered that the initial release of spores from the midgut tissues was the most critical step. The use of 2 mm beads along with enzymatic treatment with collagenase and trypsin enhanced the homogenization of tissues and the yield of released spores by approximately 2.95 times compared with the use of common 3 mm beads alone. The optimal time for the enzyme treatment was determined to be 1 hr as measured by the yield and viability of the spores. A one-step filtration using a filter paper with an $8-11{\mu}m$ pore size was sufficient for removing cell debris. This method may be useful to purify not only N. ceranae spores but also other Nosema spp. spores.

• 농약과학회지
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• 제18권2호
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• pp.53-60
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• 2014

본 연구는 상추의 재배기간 중 살포한 농약이 상추 잎 아랫부분과 윗부분의 잔류분포를 알아보기 위해 수행하였다. 살균제 boscalid와 살충제 lufenuron을 살포 후 14일까지 12회(0, 1, 2, 3, 4, 5, 7, 8, 10, 12, 13, 14일) 시료를 채취하여 잔류량 변화를 조사하였다. Boscalid는 살포 후 0일(3시간)은 상추 잎 아랫부분과 윗부분의 잔류량은 각각 18.26 mg/kg, 84.97 mg/kg이었고, 14일 후에는 0.31 mg/kg, 0.37 mg/kg으로 나타났다. Lufenuron은 살포 후 0일(3시간)은 상추 잎 아랫부분과 윗부분의 잔류량은 각각 0.91 mg/kg, 5.21 mg/kg이었고, 13일 후에는 0.06 mg/kg, 0.09 mg/kg으로 나타났다. 두 약제 살포 후 12회 조사한 잔류량은 모두 상추 잎 아랫부분이 윗부분보다 낮게 나타났다. 이와 같은 잔류분포 양상은 2013년 잔류농약이 검출된 유통 상추 잎 16건에서도 boscalid 등 9종의 잔류량 분포는 동일하게 나타났다.

• 한국토양비료학회지
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• 제47권5호
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• pp.319-323
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• 2014

This study investigates the prediction of soil chemical properties (organic matter (OM), pH, Ca, Mg, K, Na, total acidity, cation exchange capacity (CEC)) on 688 Korean soil samples using the visible-near infrared reflectance (VIS-NIR) spectroscopy. Reflectance from the visible to near-infrared spectrum (350 to 2500 nm) was acquired using the ASD Field Spec Pro. A total of 688 soil samples from 168 soil profiles were collected from 2009 to 2011. The spectra were resampled to 10 nm spacing and converted to the 1st derivative of absorbance (log (1/R)), which was used for predicting soil chemical properties. Principal components analysis (PCA), partial least squares regression (PLSR) and regression rules model (Cubist) were applied to predict soil chemical properties. The regression rules model (Cubist) showed the best results among these, with lower error on the calibration data. For quantitatively determining OM, total acidity, CEC, a VIS-NIR spectroscopy could be used as a routine method if the estimation quality is more improved.

• 농촌지도와개발
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• 제24권2호
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• pp.99-115
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• 2017

The purpose of this study is to analyze potential adoption rates and reusing patterns of the new rice direct seeding technology. The model constructed and employed in this study is a system dynamics model of farmer adoption and reusing patterns for this new technology over time. The model incorporates a causal loop diagram that explains interactions among rice cultivation subsystems with feedback loops and further attempts to build a causal loop model with stock-flow diagram for computer simulation. As one example of how the model can be used to provide insight to rice farmers, simulations are run over varying levels on the cultivation process of rice. The major finding is to demonstrate the utility of system dynamics simulation methodology in aiding the rice wet direct seeding farmers' decision making.

• 한국유기농업학회지
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• 제30권4호
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• pp.485-497
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• 2022

Agricultural environmental policies to reduce negative externalities and expand positive externalities became common around the world. However, literature regarding the efficient and effective implementation of agricultural environmental policies, such as optional direct payment, is limited. This study, thus, analyzes the relative importance for target selecting-criteria in order to enhance the cost-effectiveness of the Agricultural Environment Conservation Program in Korea. In this context, we conducted survey to 15 experts who are related in agricultural environment policies and analyzed survey results based on ANP method which can consider correlation between selecting criteria. The results show that, in the case field, "soil", "water", and "ecology" field have relative high importance than the other fields. Also, the relative importance for 'improving rural landscape', 'giving nutrient input moderately', and 'conserving agricultural heritage' activities is higher than the other activities. Furthermore, the relative importance among fields and activities of ANP is different from those of AHP. This result implies that it is necessary to consider the correlation between selecting criteria in order to design effectively. Finally, we suggest that in order to enhance the effectiveness of the program, it would be appropriate to assign differential points according to the importance of each activity when identifying appropriate farms.

• The Plant Pathology Journal
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• 제21권1호
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• pp.83-85
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• 2005

Ditylenchus acris was isolated from diseased strawberry plants. Frequently, D. acris and Aphelenchoides fragariae occur together in a strawberry plant. Both species appeared very similar in the shape, length, swimming behavior and causing symptoms, and difficult to distinguish them by a stereomicroscope. But they were easily distinguished under a compound microscope especially by their tail shape, median bulb, vulva position, and bursa.

• 한국환경농학회지
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• 제36권2호
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• pp.67-72
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• 2017

논에서 대체작물의 재배에 따른 토양 물리화학성과 작물 수량의 변화를 살펴보기 위하여 하성충적지에 분포된 규암 미사질 양토의 배수 약간양호인 토양에서 콩, 레드클로버, 공심채를 대체작물로 재배하여 3년간 경작시험을 수행하였다. 경작처리는 콩-벼-벼, 콩-콩-벼, 레드클로버-레드클로버-벼, 레드클로버-벼-벼, 공심채, 공심채-벼, 공심채-벼-벼 작부체계로, 3년차에는 모든 처리에서 논으로 복원한 다음 벼를 재배하여 토양 물리화학성과 작물 수량을 조사하였다. 앞그루가 밭일 때 토양의 용적밀도와 경도 수분함량이 감소하였고 공극률은 증가하였다. 대체작물을 2년 재배하였을 때에 1년 재배하였을 때보다 토양 입단량과 감수심이 높았다. 토양 유기물 함량은 레드클로버와 공심채를 2년 동안 재배하였을 때 높았다. 3년차에 유효인산과 치환성 칼리 함량 토양 CEC는 앞그루가 콩이었을 때 높았다. 대체작물의 1년차 생산성은 공심채가 레드클로버보다 높았으나, 2년차에는 반대였다. 3년차의 벼 수량은 앞그루가 콩과 레드클로버일 때가 공심채일 때보다 높았다.

• 원예과학기술지
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• 제30권1호
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• pp.6-12
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• 2012

Early growth, pigmentation, protein content, and phenylalanine ammonia-lyase (PAL) activity of red curly lettuces (Lactuca sativa L.) grown under different lighting conditions were investigated. Fluorescent lamps (control), blue, red, and blue plus red light-emitting diodes (LEDs) were used as light sources for 10 days. An equal proportion (1:1) of blue and red LEDs was used in the mixed radiation condition. Compared with the control, monochromic red or blue lighting increased fresh and dry weights of 'Ttuksum' and 'Jaju' lettuces. Anthocyanin synthesis was also significantly promoted by the mixed radiation of blue and red LEDs. The mixed radiation also increased the protein content and PAL enzyme activity of 'Ttuksum' leaves by about 200% compared to other treatments. Anthocyanin content was the highest in lettuces subjected to the mixture radiation of blue and red light treatment, while anthocyanin synthesis was inhibited by monochromic red light. The results of the present study indicate that growth and pigment synthesis in lettuces are significantly enhanced by exposure to mixed radiation from blue and red LEDs.

• 농약과학회지
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• 제14권2호
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• pp.133-137
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• 2010

콩탄저병의 수량에 미치는 영향을 조사하고, 요방제 수준을 설정하기 위하여 2년간 포장에서 시험하였다. 탄저병의 발병협율과 수량, 완전립수, 불완전립수, 협수와는 상관계수가 각각 -0.85, -0.78, 0.80, -0.64로 5% 수준에서 유의성이 있는 협수를 제외하고는 모두 1% 수준에서 고도의 상관이 있었다. 탄저병 발병협율(X)을 독립변수로 콩수량(Y)을 예측했을 때의 단순직선회기 모델은 Y=-1.7781X+164.22로 결정계수($R^2$)는 0.8092였다. 상기 회귀식에서 경제성을 고려하지 않고 수량에 영향을 주기 시작하는 요방제 수준은 발병협율 6.9%로 산출되었으며, 방제비용을 보상할 수 있는 경제적 피해수준 및 경제적 방제수준은 각각 발병협율 11.9%와 9.5% 로 산정되었다.

• 한국산업융합학회 논문집
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• 제25권3호
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• pp.349-356
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• 2022

Currently, the agricultural population in Korea indicates a decreasing and aging orientation. As the population of farm labor continues to decline, so farmers are feeling the pressure to be stable crop production. To solve the problem caused by the decreasing of farm labor, it is necessary to change over to "Digital agriculture". Digital agriculture is tools that digitally collect, store, analyze, and share electronic data and/or information in agriculture, and aims to integrate the several digital technologies into crop and livestock management and other processes in agriculture fields. In addition, digital agriculture can offer the opportunity to increase crop production, save costs for farmer. Therefore, in this study, for data-based Digital Agriculture, a greenhouse environment monitoring system for crop growth monitoring based on Node-RED, which even beginners can use easily, was developed, and the implemented system was verified in a hydroponic greenhouse. Several sensors, such as temperature, humidity, atmospheric pressure, CO₂, solar radiation, were used to obtain the environmental data of the greenhouse. And the environmental data were processed and visualized using Node-RED and MariaDB installed in rule.box digital. The environment monitoring system proposed in this study was installed in a hydroponic greenhouse and obtained the environmental data for almost two weeks. As a result, it was confirmed that all environmental data were obtained without data loss from sensors. In addition, the dashboard provides the names of installed sensors, real time environmental data, and changes in the last three days for each environmental data. Therefore, it is considered that farmers will be able to easily monitor the greenhouse environment using the developed system in this study.