• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.3
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• pp.208-212
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• 1993

Since ramie suckers distribute soil surface layer within 10cm depth, some of them are dead from low soil temperature in winter. An experiment was conducted to investigate the effects of various mulching methods on safe overwintering of sucker at three or four years old, fully-grown ramie plots. The sprouting dates of ramie was March 28 in transparent vinyl mulching(TPEF), April 1 in transparent vinyl mulching over cover of straw, manure or rice hull at the amount of 500kg /10a (CM), and April 6 in black vinyl mulching(BDEF). These treatments showed earlier sprouting date from 9 to 18 days than the conventional mulching with 1000 kg straw /10a the sprouting date of which was April 15. TPEF treatment showed the earliest but ununiform sprouting. In contrast, sprouts in CM treatment was uniform but emerged somewhat later compared with the treatment of TPEF. The number of stems per unit area increased 50 percent more in TPEF, and 35 to 39 percent more in CM than the treatment of conventional mulching.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.20
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• pp.63-68
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• 1975

Several high protein mutant lines(M4 plant generation, 1974) obtained from X-ray irradiated Jinheung variety were examined at three different locations for their agronomic characters, protein and grain yields. On the other hand, high protein-short culmed-early maturity mutant line No. 398 (M$_{10}$ plant generation, 1974) induced from Hokwang was crossed back to its mother to investigate the gene(s) controlling protein and its pleiotropic relation to other mutated characters. Although variation of protein percent of mutant lines from Jinheung was comparatively large depending on year and location, most of the high protein mutant lines had higher protein yield per unit area than the mother variety and their grain yields were equal to or better than the mother, being resistant to both leaf and neck blast. They were several days earlier-maturing and had shorter-culm except one mutant line. The culm length and heading date of F$_1$ between high protein mutant 398 and its mother Hokwang were intermediate. Accurate assessment of segregation of culm length and heading date in F$_2$ generation and protein percent in F$_3$ seeds will be conducted in 1975.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.3
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• pp.238-242
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• 2003

Reclaimed tidal areas for rice cultivation are irrigated with salt mixed water when there is severe drought. Therefore, we identified the critical concentration of saline water for rice growth on a reclaimed saline soil in Korea. The experiment was conducted at the Kyehwado substation of the National Honam Agricultural Experiment Station (NHAES) during 2001-2002. Two experimental fields with 0.1-0.2% for low soil salinity and 0.3-0.4% for medium soil salinity levels were used. The experiment involved four levels of salt solution mixed with sea water (at 0.1, 0.3, 0.5, 0.7%) compared with a control using tap water in a split-plot design with three replicates. Saline solution was applied only two times at seedling stage (10 DAT and 25 DAT) for 5 days. Gyehwabyeo and dongjinbyeo, japonica rice varieties, were used in this experiment. Plant height and number of tillers sharply decreased in the 0.5% saline water in low soil salinity level and 0.1% in medium soil salinity level. For yield components, panicle number per unit area and percentage of ripened grain dramatically decreased in the 0.5% saline water in low soil salinity and 0.1% in medium soil salinity level. But 1,000-grain weight of brown rice decreased sharply in the 0.5% saline water in low soil salinity and 0.3% in medium soil salinity, indicating that this component was not much affected unlike other yield components. Milled rice yield decreased significantly with saline water level in both low and medium soil salinity. In the 0.7% low saline soil, the yield index was only 36% compared with the control. In medium soil salinity, even the control plot showed only 62% yield index compared with the control in the low soil salinity treatment. Results indicated that the critical concentration of saline water for rice growth in terms of economical income of rice production was 0.5% in low soil salinity and tap water in medium soil salinity.

• The Korean Journal of Pesticide Science
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• v.4 no.1
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• pp.38-43
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• 2000

As the first step of a research on the establishment of control strategy for grapevine diseases and insects, the current status of pest control and yield losses by them were surveyed from grapevine growers of Korea. For insects, the most difficult to control was a grapevine stem borer and a grapevine clearwing moth was the next. On the other hand, several diseases including anthracnose, downy mildew, powdery mildew, bird's eye rot, leaf blight, were answered by the growers. The occurrence of the pests varied to the cultural practices. Yield loss was more serious in rainfall intercept culture than in plastic film house culture and diseases caused more loss in yield than insects did. However, the grapevine grower's potential for the identification of the kinds of pests was not high enough. When the pest was observed, the growers consulted mainly with local pesticide dealers or neighbouring growers and usually applied the pesticides prescribed by the dealer. More than half of the growers did not use pest control calendar, and most of the growers applied pesticides before any symptom appeared. Also, more than half of the growers applied mixture of at least more than 1 kind of pesticide and nutrients. Insecticides were applied less than 5 times during the season, but it was more than 6 times for fungicides. In the pesticide selection, the growers checked control effect first, regardless of the registration, and the pest control cost per unit area varied very much depending on the growers.

• Korean Journal of Food Science and Technology
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• v.14 no.2
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• pp.156-161
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• 1982

Three plastic film solar dryers covered with different film layer were constructed by modifying farm vinyl house and studied their performance. The collection efficiency and temperature raising of type C which was covered with double layers of transparent PE and black PVC film was most efficient, followed after B covered with double layer of transparent PE film and type A covered with single layer transparent PE film. The inside temperature of type C was average $18^{\circ}C$ higher than ambient temperature and its collection efficiency showed 31.5% with air flow rate of $3.8m^3/min$. The solar energy collection efficiency of type C was increased in proportion to air flow rate up to 60.2% at $11.3m^3/min$. In demonstration drying test of red pepper in type C, drying capacity per unit area was 2.5 times higher than that of conventional solar drying on straw mat and drying time shortened to about half.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.3
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• pp.175-184
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• 2012

Changes of fish assemblage inhabiting around Dae Island in Gwangyang Bay, Korea were investigated using a small beam trawl monthly from March 2009 to February 2010. These data were compared with those obtained in previous studies(1990~1991 and 1995~1996) at our study sites. A total of 8,133 fish belonging to 74 species in 38 families were collected. Leiognathus nuchalis, Argyrosomus argentatus, Acentrogobius pellidebilis, Sillago japonica, Apogon lineatus, Thryssa hamiltoni, Repomucenus richardsonii, Pholis nebulosa, Pleuronichthys cornutus, Hexagrammos otakii, and Limanda yokohamae dominated, and these were responsible for 89.5% and 58.9% in the number of individuals and in biomass, respectively. These were primarily small species or early juveniles of larger species. Seasonal variation in both species composition and abundance was large: the peak number of fish species occurred in May and October 2009, whilst both number of individuals and biomass were the highest in May 2009. Fish numbers as well as biomass was lowest in January and February 2010. Seasonal changes in the abundance of fishes corresponded with temperature. Compared with the previous studies, the total number of individuals and biomass per unit area($m^2$) were higher, and the predominance of L. nuchalis occurred while abundances of Liparis tanakai were significant decreased. These results seemed to be change of species composition in fish assemblage which was due to variation of annual environmental characteristics in Gwangyang Bay.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.7
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• pp.511-515
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• 2011

The aim of this study was to investigate the efficiency of temperature, light intensity and pH on the growth rate of Chlorella vulgaris (C. vulgaris). The size of C. vulgaris (FC-16) was $3-8{\mu}m$, having round in shape. The cells of C. vulgaris (FC-16) was cultured in the Jaworski's Medium with deionized water. To evaluate the efficiency of temperature, light intensity and pH on the growth rate of C. vulgaris, six different fractions of temperature ($10^{\circ}C$, $15^{\circ}C$, $20^{\circ}C$, $25^{\circ}C$, $30^{\circ}C$, $35^{\circ}C$), various light intensities ($100-800{\mu}Em^{-2}s^{-1}$) and seven different fractions of pH (3, 4, 5, 6, 7, 7.5, 9) were prepared. The growth rate of C. vulgaris cultivation was approximately 5.2 to 5.5 times faster, the concentration of Chlorophyll a was also 5 to 5.5 times higher, and cell volume per unit area was 14% higher at $25^{\circ}C$ to $30^{\circ}C$ than those at $10^{\circ}C$. Therefore, the optimal temperature for cultivation of C. vulgaris was estimated $25^{\circ}C$ to $30^{\circ}C$. The growth rate of C. vulgaris increased slowly up to 5 days, exploded after 5 days until 15 days, and then stoped after that. The optimum cultivation period of C. vulgaris was estimated as 15 days. The optimum pH for the growth rate of C. vulgaris was determined pH 7 to 7.5.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.480-488
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• 2018

The development of information and communication technology has been carried out actively in the field of agriculture to generate valuable information from large amounts of data and apply big data technology to utilize it. Crops and their varieties are determined by the influence of the natural environment such as temperature, precipitation, and sunshine hours. This paper derives the climatic factors affecting the production of crops using the garlic growth process and daily meteorological variables. A prediction model was also developed for the production of garlic per unit area. A big data analysis technique considering the growth stage of garlic was used. In the exploratory data analysis process, various agricultural production data, such as the production volume, wholesale market load, and growth data were provided from the National Statistical Office, the Rural Development Administration, and Korea Rural Economic Institute. Various meteorological data, such as AWS, ASOS, and special status data, were collected and utilized from the Korea Meteorological Agency. The correlation analysis process was designed by comparing the prediction power of the models and fitness of models derived from the variable selection, candidate model derivation, model diagnosis, and scenario prediction. Numerous weather factor variables were selected as descriptive variables by factor analysis to reduce the dimensions. Using this method, it was possible to effectively control the multicollinearity and low degree of freedom that can occur in regression analysis and improve the fitness and predictive power of regression analysis.

• The Korean Journal of Pesticide Science
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• v.7 no.1
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• pp.66-73
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• 2003

Actual pesticide usage in fruit vegetable cultivation was surveyed. Usage trend of in of vidual pesticides was evaluated to provide the data for the development of indicators of environmental impact and the production of safe agricultural products. The amount of the pesticides used for fruit vegetables was revealed in order of fungicide> insecticide> herbicide, showing that the portion of fungicide to the total amount used was about 70 to 80%. Main fungicides used on fruit vegetables were mancozeb, thiophanate-methyl propineb, etc while the insecticides were imidacloprid, milbemectin, methomyl, etc. Main formulation types of pesticide were wettable powder and emulsifiable concentrate. By different fruit vegetables and cultivation patterns, pesticide use per unit area was revealed red pepper (field cultivation, 13.2kg/ha), cucumber (field cultivation, 12.4kg/ha), sweet melon (field cultivation, 11.2kg/ha) as high pesticide use crops, meanwhile, water melon (greenhouse cultivation, 1.2kg/ha), sweet melon (greenhouse cultivation, 2.2kg/ha), strawberry (field cultivation, 2.8kg/ha) as low pesticide use crops.

• Korean Journal of Plant Taxonomy
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• v.37 no.4
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• pp.447-476
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• 2007

The pollen and revisional study aimed for an elucidation of taxonomic delimitation and relationship of Thalictrum taxa in Korea, especially among the morphologically confused taxa. Pollen grains of 63 populations of 17 taxa were investigated by light and scanning electron microscopy. Although pollen morphology was not useful for the species classification, it revealed a tendency in which Sects. Physocarpum, Erythrandra and Tripterium having broad filaments and round-tipped anthers possess closer distance between adjacent pores, less echinus number per unit area, smaller pollen, and higher echinus, on the contrary to Sects. Omalophysa, Camptonotum and Thalictrum having filiform filaments and acute-acuminate- or more or less round-tipped anthers. The palynological result did not support several section system by Tamura (1992) but one section system by Lecoyer (1885). If a infrasectional system is needed, it was suggested that the system dividing the section into two (Clauiformes and Filiformes sensu Lecoyer) would be natural on the basis of stamen and pollen characteristics. Revisional study found out that 17 taxa(16 species) of Thalictrum are distributed in Korean including T. filimentosum which presence in Korea was not confirmed.