• Journal of The Korean Society of Grassland and Forage Science
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• v.12 no.2
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• pp.104-110
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• 1992

This experiment was carried out to determine the effects of nitrogen(N) fertilization levels(0. 120, 240 and 360 kg/ha/y) on seasonal nitrate nitrogen($NO_3$-N) concentration and water soluble carbohydrate (WSC) content of grasses grown under shading condition. The plants were sampled on 7. 14, 21, 28 and 35 days after harvesting in spring(May), summer(July) and autumn(September), 1988. respectively. Shading degree was controlled artificially ca. 45-50%, and each annual level of N was distributed 5 times equally. The $NO_3$-N concentration of grasses was very low(0.064 %) in spring, high in summer(O.l98 %) and autumn(0.234%), and NO,-N was slightly decreased with growing of grasses. Also the NO,-N concentration of grasses was increased significantly with increasing level of N. In spring, the $NO_3$-N of grasses was very safety(less than 0.1 %), regardless of plant height and N level. In summer and autumn, however, plant heights of below 40 cm(summer) and 44 cm(autumn), and N levels of over 210 kg(summer) and 140 kg(autumn) were over toxic level to animals, respectively. The WSC content of grasses was slightly decreased with grass growth. and significantly decreased with high level of N. From the above results, it is suggested that 200 kg/ha of N in this experiment is effective for forage quality. Also a little more amount of N(50-70kgltimes) in spring. and low level of N(20-30 kgltimes) in summer and autumn season may be desirable on woodland posture.

• Journal of Sericultural and Entomological Science
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• v.14 no.1
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• pp.37-42
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• 1972

This investigation was conducted to measure the effects of silkworm diseases on the cocoon crepe. The sample farmers were selected at three areas in Korea. a. Banga Ri, Namsa Myoen, Yongin Kun, Kyoenggi Do b. Moorim Ri, Yakmok Myeon, Chilkok Kun, Kyeongsangbuk Do c. Oero Ri, Buksam Myeon, Chilko Kun, Kyeongsangbuk Do 1. Reduction ratio of crops by the silkworm disease was 5.5% in spring season, and 8.9% in the autumn but 7.2% in a year. Including disease damaged cocoons being spoiled cocoons, it was 8.3%. 2. The ratio of disease-damage by the polyhedrosis virus and flacherie was 17.8% of whole disease at young instar and was 82.2% at advanced instar which showed highest ratio. 3. Average production amount of the cocoon was 27.74kg, The reduction amount by the silkworm disease against the estimated production aomunt was 2.411kg. 4. Reduction of amounts by unknown factors was 3.611 kg. This was 1.5 times of reduction amount by the disease. This nay be chiefly due to the missing silkworms and spoiled cocoons. 5. Ratio of farmers harvesting stable cocoon crops was 54.7% in spring rearing season but 21.9% in autumn. 6. Damage ratio of factors other than the silkworm disease was 10.70% and it was 17.87 % of total mortality.

• Journal of Biosystems Engineering
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• v.39 no.4
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• pp.253-260
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• 2014

Purpose: This study investigated the harvesting properties of the giant miscanthus (Miscanthus ${\times}$ giganteus) to measure the required mowing power for different stem conditioning methods in order to shorten the drying time after mowing and the bale density so that the crop can be used as biomass in the winter season. Methods: The required mowing power and bale density were measured using a power measurement device, three different mower-conditioners, and a mid-sized round baler under different working speeds and conditioning methods. Results: For the various mower-conditioners, the average stem length from mowing was 0.86-0.91 m, and the available working speed was 1.6 m/s. The steel roller-type mower-conditioner showed better stem conditioning but could not mow over a working speed of 1.6 m/s. The required average power of the mower-conditioners varied from 23.8 kW for the steel roller-type rotary disk mower-conditioner with a working width of 2.4 m to 37.2 kW for the flail-type rotary disk mower-conditioner with a working width of 3.2 m at a working speed of 1.6 m/s. The bale densities were $155.8-172.2kg/m^3$. The highest bale density was measured for stems with no conditioning and a moisture content of 11.3% (d.b.) mowed by the rotary disk mower. The bale density was affected by the mowing method because of the low moisture content of the miscanthus stems. Conclusions: In terms of the working performance and conditioning statue, the steel roller-type mower-conditioner is a better choice at a working width of 2.4 m, while the flail finger-type mower-conditioner is better at a working width of 3.2 m. The type of mower-conditioner used for giant miscanthus harvesting should be determined by considering the harvest area, workable period, and working performance of a mower-conditioner and baler during the winter.

• Journal of Biosystems Engineering
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• v.38 no.4
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• pp.240-247
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• 2013

Purpose: This study was conducted to develop a rubber-crawler type vehicle as a traveling device for harvesting water-dropwort cultivated in water contained paddy rice field in winter season. Methods: A commercial rubber-crawler type vehicle was used to investigate application of rubber crawler to the paddy rice field as preliminary test. As the result of the preliminary test, a both prototype traveling device with rubber crawlers for a water-dropwort harvest was designed with inclination of $45^{\circ}$ at the front-end and rear-end of crawler under the basic water depth of 0.6 m in the paddy rice field. The device was fabricated and attached to the experimental harvesting test devices on the front of the prototype vehicle. The size of the prototype crawler vehicle with a harvesting part is $2,800{\times}1,460{\times}1,040 $ (mm) ($L{\times}W{\times}H$) with weight of 9.21 kN (maximum). Sizes of the crawler of prototype vehicle are ground contact length of 900 mm, width of 180 mm, height of 1,070 mm and distance between center to center of crawlers of 720 mm. The side-overturn angle of the prototype was $26.4^{\circ}$. Results: Driving performance of the prototype vehicle in water contained paddy field were good at both forward and reverse (backward) directions as weights were applied. The drawbar pull and the maximum sinking depth of the prototype vehicle were 3.5 kN and 0.13 m respectively at water depth of 0.5 m, when the weight and bearing capacity of the prototype rubber crawler in the paddy field were 8.51 kN and 26.3 $kN/m^2$, respectively. Conclusions: Results of the driving test performance of the prototype crawler in paddy rice field at the water depth of 0.5 m were satisfactory. The prototype had enough drawbar pull and driving ability in the deep water contained paddy field.

• Journal of Korea Water Resources Association
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• v.53 no.11
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• pp.961-971
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• 2020

The Intergovernmental Panel on Climate Change (IPCC) reported that the amount of precipitation in South Korea would increase regardless of the reduction of Greenhouse Gas (GHG) emissions. Moreover, the temporal and spatial rainfall variation would also increase in the future. Due to the geographic allocation of Korea, more than 80% of the annual precipitation occurs in the wet season from early July to late September. It is expected that the average precipitation in this period will increase from the Representative Concentration Pathways (RCP) scenario projections. These predictions imply an increased variability of available water resources. Rainwater harvesting system is widely used as an alternative water resources today. This study introduces a RBSN (rain barrel sharing network) as an efficient way to utilize alternative water resources under the RCP scenarios. The concept of RBSN combines individual rainwater harvesting system to a sharing network, which make the whole system more reliable. This study evaluated a RBSN in South Korea composed of four users based on a storage-reliability-yield (SRY) relationship. The study area comprises all 17 provincal areas in South Korea. The result showed a huge benefit from a RBSN in Korea under the historical rainfall condition. Even in the climate change condition, the results showed that a RBSN is still beneficial but the changes in reliability are different depending on provinces in Korea. The results of this study shows that a RBSN is a very effective and alternative measure that can deal with the impacts of climate change in the near future.

• Journal of Bio-Environment Control
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• v.21 no.3
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• pp.276-280
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• 2012

This study was conducted to determine the ideal beginning date of plastic house optimum heating for off-season (December) production of asparagus. To achieve this, the 1.6-year-old 'Green tower' asparagus was cultivated in Jeju area ($33^{\circ}$28.110N, $126^{\circ}$31.076E) and the yield and quality among 7 different beginning dates of heating from Oct. 25 to Jan. 20 with 15-days interval were compared. The heating was controlled to maintain the inside temperature was higher than $20^{\circ}C$, But the plastic house was ventilated when the inside temperature rose to $30^{\circ}C$. Days to sprouting took longer as heating dates were delayed. Days to sprouting took 52 days in heating at December 30, and the days were shortened thereafter. As the beginning of heating was delayed, sprouting of asparagus was retarded. Among treatments, days to sprouting was 52 days and longest when the heating began on December 30. When the heating began on October 25, harvest was earliest and started on 7 November. When the heating began on November 15 and 30, harvest started on November 30 and December 18, respectively. Harvesting started on November 7 for October 25 heating, November 30 for Nov. 15 heating, and December 18 for November 30 heating, respectively. When the heating began was done after December. 15, harvesting was possible after early January. The number of spear, spear weight and yield were highly increased in the treatments of heating after January. 10 when the asparagus dormancy was broken. In the case of heating dates were before the asparagus dormancy breaking, the total yield was highest in November 15 heating with 607 kg/10a. The marketable yield of November 15 heating was 386kg/10a, which was twice higher than the 193 kg/10a of October 25 heating. Accordingly, it is recommended to start heating on November 15 for the production of off-season (December) asparagus in Jeju. Therefore, the optimum heating date to start was November 15 for the improvement of quality and yield of off-season (December) asparagus in Jeju area.

• Current Research on Agriculture and Life Sciences
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• v.11
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• pp.19-23
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• 1993

This study was conducted to investigate contents of inorganic constituents, free sugars and catalpol in the Rhizoma of Rehmannia glutinosa as different growth stages. With the approach of harvesting season, the variations of their contents were as follow. The contents of P, K, Ca, Mg, Cu and ash in the Rhizoma decreased, whereas the contents of Fe, water and ethanol extract increased. The contents of total sugar, sucrose and galactose in the Rhizoma decreased, but the fructose and catalpol contents in the Rhizoma were increased.

• International Journal of Industrial Entomology and Biomaterials
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• v.2 no.1
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• pp.75-78
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• 2001

The whitefly, Dialeuropora decempuncta Quaintance and Baker (Homoptera : Aleyrodidae) causing considerable damage to mulberry, Morus alba. Crop loss caused by the whitefly was estimated in mulberry. Quantitative yield loss was estimated on the basis of harvest data from both sprayed and unsprayed plots. Data on pest incidence has been recorded at weekly intervals in both sprayed and unsprayed plots from 30 th day of plant age till harvesting i.e., 60 days after pruning in August October season. An attempt has been made to establish a relationship between whitefly population and percentage of crop loss due to it. Percentage of crop loss due to whitefly has got a linear relationship with the whitefly population. An initial population of 24 adults/top leaf would be able to cause 24% loss (l,630 Kg leaf/ha ) in a period of 30 days. Economic analysis postulates that application of pesticide can stove a net amount of 1,630 Kg leaf/ha which is sufficient to produce 67.65 Kg of additional multivoltine cocoons. This determines the cost/benefit ratio which will enable to workout the economics of management practices.

• Journal of Biosystems Engineering
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• v.24 no.3
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• pp.225-234
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• 1999

This study was performed as a basic research for establishing an objective quality evaluation method on whole bulbs of garlic. The size of a whole bulb of garlic, the number and the uniformity of complete individual garlics, and the existence of bad individual garlics in the whole bulb of garlic were selected as quality grading factors. Quality discrimination algorithms with machine vision techniques were developed and verified for the four factors based on morphological and physical features of whole bulbs of garlic. Based on the results, the size discrimination by the projected area of a whole bulbs of garlic suggested four grading levels and the algorithm for predicting the number of complete individual garlics based on the peaks on its projected boundary showed ${\pm}$0.78 prediction error. In addition, the uniformity represented by coefficient of variation could be divided into four levels, but the algorithm for discriminating the existence of bad individual garlics in a whole bulb of garlic was not effective.

• Journal of Ginseng Research
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• v.32 no.4
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• pp.347-356
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• 2008

Forest-grown American ginseng (Panax quinquefolius L.) is exposed to daily and seasonal light variations. Our goal was to determine the effect of understory light changes on the maximum quantum yield of photosystem II, expressed as $F_v/F_m$, and photosynthetic pigment composition of two-year-old plants. Understory light photon flux density and sunfleck durations were characterized using hemispherical canopy photography. Our results showed that understory light significantly affected the $F_v/F_m$ of American ginseng, especially during the initial development of the plants when light levels were the highest, averaging 28 mol $m^{-2}d^{-1}$. Associated with low $F_v/F_m$ during its initial development, American ginseng had the lowest levels of epoxidation state of the xanthophyll cycle of the season, suggesting an active dissipation of excess light energy absorbed by the chlorophyll pigments. As photon flux density decreased after the deployment of the forest canopy to less than 10 mol $m^{-2}d^{-1}$, chlorophyll a/b decreased suggesting a greater investment in light harvesting pigments to reaction centers in order to absorb the fleeting light energy.