• 한국토양비료학회지
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• 제48권3호
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• pp.170-179
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• 2015

This study was carried out to investigate the sustainable agriculture of no-tillage technique to minimize tillage problems under rain interception green house condition including recycling of the ridge and the furrow for following cultivation in Korea. Chemical properties in soils were investigated at 3-years after cultivation at conventional tillage [CT; 2-years no-tillage (2009-2010) and 1-year (2011) tillage] and no-tillage [NT; 2009-2011] field. Soil pH maintained between 5.8 and 6.0 irrespectively tillage and no-tillage. Salinity (EC), contents of total nitrogen (TN), cation exchange capacity (CEC), and exchangeable cations (K, Ca and Mg) in soil were remarkably higher in CT than in NT treatment. Salinity (EC), contents of OM, TN, CEC, and exchangeable cations in top soil and subsoil indicated higher deviation in CT than NT treatment. Organic matters and inorganic matters in soil were positive (+) correlation. Suppression of pepper growth and increase of yield were observed in no-tillage soil compared with tillage soil. These results indicated that no-tillage technique in crop culture could play an important role with respect to chemical properties in silt loam soil.

• Journal of Biosystems Engineering
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• 제30권2호
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• pp.102-109
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• 2005

Water consumption at the farm is up to 48 percent of water resource of South Korea while manufacturing industry's is only $9.6\%$. The area of arable land is 2,077,067 ha and 27 percent of it is used for growing fruits and vegetables using furrow or surface irrigation at the greenhouse. Surface irrigation at the greenhouse for fruits and vegetables has problems such as over watering and insufficient supply of water to the fine roots of the plant. However, the research on the new method of irrigation to save water usage is few. The characteristics of soil wetting was measured for using surface irrigation and underground trickle irrigation method where water was supplied at 10, 15, 20, and 25 cm beneath the surface ground. Followings are summary of this study. 1. The efficiency of underground trickle irrigation was expected to be as high as twice of surface irrigation such as drip watering or sprinkling. 2. This improvement could be possible by using less than $50\%$ of irrigation water than surface irrigation to supply similar amount of water near fine roots. 3. Surface irrigation causes soil compaction as deep as 20 cm below the surface ground which reduces soil porosity and root respiration ending up developing less fine roots. 4. Underground trickle irrigation can prevent overdamping in the greenhouse since it does not over wet the surface soil. At winter, the amount of agricultural chemical usage could be reduced since this irrigation method does not develop blight or crop disease from condensation of water vapor.

• 원예과학기술지
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• 제18권6호
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• pp.787-791
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• 2000

고랭지 결구상추 기계정식시 두둑형상은 둥근두둑의 경우 두둑 폭 35-40cm, 두둑높이 15-20cm, 고랑폭 20-30cm이 적당하였다. 식부심은 4-5cm였으나 평탄정도가 불량한 곳에서는 정식기의 불안정으로 너무 깊게 심기거나 얕게 심기는 경우가 있었으며, 포장정식 후 충분한 관수로 적정수분을 유지할 수 있도록 하는 것이 중요하였다. 종합적으로 결구상추 기계정식시 정식노력 절감율은 관행대비 93% 이상 절감효과를 보였고, 재식거리는 1조식으로 $60{\times}20cm$ 또는 $60{\times}25cm$로 정식하는 것이 적합한 것으로 나타났다.

• Journal of Biosystems Engineering
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• 제4권1호
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• pp.58-66
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• 1979

동력경운기용 두류의 무경운 파종기에 부착하여 사용하는 구절기중에서 소요견인력이 작고 구절작업정도가 양호한 구절기의 개발을 위한 기초자료를 얻기 위하여 구동식 토조에 인공강토를 채우고 원판형 및 호우형 구절기의 소요견인력과 이에 영향을 미치는 인자들의 관계를 구명코자 실내모형 확험을 실시하여 다음과 같은 결과를 얻었다. 원판형 구절기에 대하여 직경별로 조립각을 $8^{\circ}$ 와 $16^{\circ}$, 경심을 3 cm 와 6cm로 변화시키면서 2.75cm/sec의 속도로 견인력을 측정한 결과 원판의 직경이 약 28cm인 경우에 견인력이 최소로 나타났고, 직경이 이보다 크거나 작은 때는 견인력이 증가하는 경향을 나타냈으며 비저항도 대체로 비슷한 경향이었으나 원판의 직경이 약 30cm 일 때 최소로 나타났다. 종자파종의 심도조절을 목적으로 작구심(3cm 및 6 cm)과 견인력과의 관계를 조사하였던바, 경심과 견인력과의 관계는 거의 직선적인 변화를 나타냈으며 견인력에 영향을 미치는 인자중에서 경심의 영향이 가장 컸음을 알 수 있었다. 일반적으로 조립각 미 주행속도에 별 영향없이 경심 3cm 및 6 cm 공히 견인력은 직경 약 28 cm에서 , 비저항은 약 30cm에서 최소의 값을 나타내었다. 파종기의 작업성능과 관계가 깊은 주행속도 및 파시의 조절을 목적으로 원판의 조립각과 주행속도가 견인력에 미치는 영향을 조사했던 바, 조립각과 주행속도가 증가함에 따라 모두 견인력이 증가하는 경향을 나타내었으나 견인력에 미치는 영향은 주행속도가 더욱 크게 나타났다. 원판형 구절기와 호우형 구절기를 비교하기 위하여 쐐기각이$16^{\circ}$ 이고 리프트 각이 $20^{\circ}$ 인 호우형 구절기와 조건이 비슷한 조립각$16^{\circ}$ 의 원판형 구절기의 견인특성을 비교한 결과 직경 30cm 인 원판형의 경우는 비저항이 0.35-0.5kg/$cm^2$인데 비해 호우형의 경우는 0.71-1.02kg/$cm^2$로 나타나 호우형의 견인저항력이 평균 2 배정도 크게 나타났고 작구상태고 원판형의 경우보다 불량하였다.

• Journal of Biosystems Engineering
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• 제39권1호
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• pp.1-10
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• 2014

Purpose: This research was conducted to evaluate feasibility of a crank-type walking cultivators for weeding in furrowed upland. Methods: A walking cultivator developed by RDA was selected and evaluated with its working speed (S), cultivation depth (CD) and weeding performance (WP). The evaluation was performed in upland field on July and August, 2012. Also kinematic analysis of the machine was performed to draw out design improvements. Results: S in flat, uphill and downhill were about 0.11 m $s^{-1}$, 0.11 m $s^{-1}$, and 0.13 m $s^{-1}$ respectively. It was found that S had a low relevance with user conditions. The CD was 35 ~ 40 mm which was satisfied with the RDA guide for weeding machine. A wide variation was observed in values of WP depending on the growth stages of weeds and field conditions. The cultivator showed low performance in eliminating the well-grown weeds. Kinematic simulation revealed that high forward speed caused a high ratio of un-weeded area. Conclusions: The weeding performance of the cultivator was satisfactory for weeds in early growth stage but it showed difficulties in handling on up-slope and in entering up-land. Specifically, the weight of the cultivator was judged as overweight for female workers. The crank-hoe type cultivator was judged as unsuitable for small walking type machine due to weight of the four-bar linkage system. Kinematic analysis revealed that the ratio of crank speed to the ground speed must be 850 rpm s $m^{-1}$ (255 rpm based on 0.3 m $s^{-1}$) or greater to avoid uncultivated area. Selection of forward speed is a decisive factor in designing the weeding cultivator.

• 해양환경안전학회지
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• 제17권2호
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• pp.131-136
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• 2011

컴퓨터 비젼을 이용한 항행선박의 항적을 계산하고 교통량을 측정하는 방법은 해양사고의 예방관점에서 사고발생 가능성 여부를 예측해 볼 수 있는 유용한 방법이다. 본 연구에서는 컴퓨터 비젼을 이용하여 영상축소, 미분연산자, 최대 최소값 등을 이용하여 선박을 인식한 후 실세계 상에서의 좌표 값을 계산하여 실시간 항적을 전자 해도에 표시함으로서 해상 구조물과의 충돌여부를 직접 육안으로 확인 할 수 있는 알고리즘을 개발하였다. 본 연구에서 개발된 알고리즘은 영역 정보를 기반으로 개발되었기 때문에 점 정보에 의존하고 있는 기존 레이더 시스템의 단점을 보완하는 장점을 지니고 있다.

• Journal of Microbiology and Biotechnology
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• 제23권3호
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• pp.289-296
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• 2013

Cryptomonads are unicellular, biflagellate algae. Generally, cryptomonad cells cannot be preserved well because of their fragile nature, and an improved methodology should be developed to identify cryptomonads from natural habitats. In this study, we tried using several cytological fixatives, including glutaraldehyde, formaldehyde, and their combinations to preserve field samples collected from various waters, and the currently used fixative, Lugol's solution was tested for comparison. Results showed that among the fixatives tested, glutaraldehyde preserved the samples best, and the optimal concentration of glutaraldehyde was 2%. The cell morphology was well preserved by glutaraldehyde. Cells kept their original color, volume, and shape, and important taxonomic features such as furrow/gullet complex, ejectosomes, as well as flagella could be observed clearly, whereas these organelles frequently disappeared in Lugol's solution preserved samples. The osmotic adjustments and buffers tested could not preserve cell density significantly higher. Statistical calculation showed the cell density in the samples preserved by 2% glutaraldehyde remained stable after 43 days of the fixation procedure. In addition, DNA was extracted from glutaraldehyde preserved samples by grinding with liquid nitrogen and the 18S rDNA sequence was amplified by PCR. The sequence was virtually identical to the reference sequence, and phylogenetic analyses showed very close relationship between it and sequences from the same organism. To sum up, the present study demonstrated that 2% unbuffered glutaraldehyde, without osmotic adjustments, can preserve cryptomonads cells for identification, in terms of both light microscopy and phylogenetic analyses based on DNA sequences.

• 식물분류학회지
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• 제42권2호
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• pp.171-177
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• 2012

한반도 미기록식물인 Chaerophyllum tainturieri Hook. (산형과)와 Barbarea verna (Mill.) Asch. (십자화과) 2종을 서울과 부산에서 각각 발견하였다. 전호아재비로 이름붙인 C. tainturieri는 서울 상암동의 월드컵공원에서 확인되었다. Chaerophyllum속은 국내에서는 처음으로 본 연구에서 보고되는 미기록속이다. 형태적 유사종인 무산상자속(Sphallerocarpus Besser ex DC.) 식물과 비교하여 열매가 통모양이고, 분과의 갈라지는 틈에 1개의 유관이 있다는 특징으로 구별된다. 봄나도냉이로 이름붙인 Barbarea verna는 부산 금사동의 수영강 둔치에서 확인되었으며, 동속 식물인 나도냉이(B. orthoceras)와는 근생엽의 길이가 4-8 cm이고, 근생엽이 4-11쌍으로 갈라지며, 종자의 길이는 1-2 mm라는 특징으로 구별된다.

• 한국토양비료학회지
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• 제51권2호
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• pp.79-89
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• 2018

Subsurface drip irrigation (SDI) system is considered one of the most effective methods for water application. A 2-year field study was conducted to investigate the effect of SDI systems with various dripline spacing (0.7 or 1.4 m) and position (under furrow or ridge) on soybean (Glycine max L.) production at a sandy-loam soil in Miryang, South Korea. For 2016-2017, average grain yield in SDI irrigated plots, $3.16Mg\;ha^{-1}$, was statistically greater than rainfed irrigated plot ($2.63Mg\;ha^{-1}$). Soybean grain yield averaged $3.25Mg\;ha^{-1}$ for the 0.7 m dripline spacing and $3.07Mg\;ha^{-1}$ for the 1.4 m spacing for the two-year period compared to a rainfed irrigated average of $2.63Mg\;ha^{-1}$ for the same period. Soybean treated with SDI system had significantly greater values of normalized difference vegetation index and stomatal conductance, indicating that soybean plants in SDI plots had greater photosynthetic and stomatal activity due to the higher water availability in soil. Irrigation water use efficiency (IWUE) was greatest in the plot of 0.7 m spacing installed under ridge position than any other plot across growing season. Average soil water content in plots with 0.7 m dripline spacing was $0.21m^3\;m^{-3}$ at 5 cm depth layer, which was 45% greater compared to the plots with 1.4 m spacing, even though the gross irrigation amounts were greater in 1.4 m spacing plots. It is concluded that wide dripline spacing (1.4 m) is probably the more economical installation design for SDI system compared to 0.7 m spacing in this study soil because the initial cost for dripline may be reduced with wide spacing design, even though the IWUE is greater in the plot of 0.7 m dripline spacing.

• 한국자원식물학회지
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• 제28권4호
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• pp.541-545
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• 2015

This study investigated the effect of planting density on growth and yield of elephant garlic. Three planting densities of 20 × 20, 20 × 15, and 20 × 10 ㎝ were tested with the furrow width fixed at 120 ㎝ for the evaluation of elephant galic growth and yield. The average date of emergence was middle and late November, requiring about 30 days for the all emergence. For the flowering, 221 days after sowing were required in all the treatments. Plant height and leaf growth were not significantly different according to the planting density. Flower stalk was shorter when planting density was narrow. The L/D ratio was decreased to form oval shape when planting density was narrow. The yield of elephant garlic was 1,811 ㎏ /10a in planting density 20 × 20 ㎝, 2,375 ㎏/10a in 20 × 15 ㎝, and 2,838 ㎏/10a in 20 × 10 ㎝ plot. The marketable garlic ratio was highest as 1,593 ㎏/10a in planting density of 20 × 15 ㎝.