• Korean Journal of Soil Science and Fertilizer
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• v.27 no.4
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• pp.269-274
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• 1994

An experiment was carried out to investigate the effects of irrigation period on the yield and quality of melon (Cucumis melo L.) cultivated in green house 1992~1993. Four different irrigation period was applied ; from transplanting to harvest(Irrigation I), from initial flowering to 35 days after flowering(Irrigation II), from initial flowering to 20 days after flowering(Irrigation III), from initial flowering to 5 days after flowering(Irrigation IV). The water was applied by drip irrigation when the soil water potential of 15cm depth reach at -0.5bar. The results obtained were as follows ; 1. The amount of water applied during the periods were 170.5mm, 145.0mm,126.9mm and 78.8mm for irrigation period I, II, III and IV, respectively. 2. Average evapotranspiration during the cultivation of melon was 3.31mm/day. Evapotranspiration was the highest at the period from 5days after flowering to 15days after flowering. 3. The total yield was increased with the higer amount of water applied, and the yield was in the order of Irrigation I, II, III and IV. However, the yield with economically high quality was the highest in Irrigation III. 4. The sugar content and quality of Net form were decreased with higher irrigation amount.

• Korean journal of applied entomology
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• v.24 no.1 s.62
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• pp.29-33
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• 1985

Every plant in $990m^2$ onion field was inspected for damages by the onion maggot. Maps were constructed every ten days to show which plants were infested and which were not from April 11 to May 21, 1984. The maps were sectioned into squares one of which contains 80 onion plants and the counts of damaged onions in each square were fitted to poisson and negative binomial distribution and tested by chi-square. We argue that the satisfactory fitness of the expected negative binomial $[P(x^2)>0.05]$ provided a useful description of the spatial distribution patterns of the damaged onions. Edge effect was tested by the differences of damage ratio and variance/mean ratio (${\sigma}^2/m$) between edge and center part. The result showed that the damage ratioes and variances of all the periods, ${\sigma}^2/m$ values after May 1 were greater in edge part than in center part. Again, the maps were sectioned into four blocks and the squares (sample units) were sectioned into quadrants. By application of the variance component technique, it was suggested that $2{\sim}8$ sample units for 5% sampling error and $1{\sim}2$ sample units for 10% error should be sampled randomly to estimate the damage ratio when $2{\sim}3$ quadrants were inspected.

• Korean Journal of Ecology and Environment
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• v.49 no.2
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• pp.89-101
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• 2016

To elucidate occurrence patterns of $C_4$ plants in agroecosystems, we surveyed flora inside fields and embankments in 222 sites in farming lands in summer and fall, 2013. We also observed Kranz anatomy and analyzed carbon stable isotope to classify photosynthesis types. Our study observed total 54 species of $C_4$ plants in 33 genera and 9 families of vascular plants besides cultivated crops occurring in farming fields. The most common species was Portulaca oleracea L. followed by Digitaria ciliaris and Echinochloa crusgalli (L.) P. Beauv. var. crusgalli among the $C_4$ plants. The ratios of $C_3$ and $C_4$ species number to total number of species tended to maintain constant regardless of survey times and habitat types. The proportion of $C_4$ species to the total number of species were more influenced by the number of $C_3$ species than those of other types in the surveyed sites. Sizes of cultivation areas did not affect the proportions of $C_4$ plants. Increasing number of simultaneous weeding methods, especially with cutting method, appeared to decrease the number of $C_3$ plants. On the other hand, as the number of cultivated crops increased, both $C_3$ and $C_4$ plants increased but the proportions of $C_4$ species remained. We interpret our results that proportion of $C_4$ species in agroecosystems, appear to be dependent on the number of $C_3$ species, which in turn, appear to be affected by cultivation methods.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.3
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• pp.243-250
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• 1981

Soybean, azuki-bean and mungbean were cultivated at different growing conditions, May 10, June 9, July 9 seeding, and May 10 seeding-short day treatment, to investigate the distribution of flowering date and the variation of pod/flower ratio. The growth habit type of the soybean variety used was determinate, but the azuki-bean and mungbean varieties used showed indeterminate growth habit. The pod/flower ratio ranged 38 to 48% for soybean, 23 to 34% for azuki-bean and 46 to 60% for mungbean along with growing conditions. Flower abscission for soybean and mungbean, and pod abscission for azuki-bean affected more on the number of matured pods. Soybean showed once full blooming period, but azuki-bean and mungbean showed two or three times full blooming period except July 9 seeding plot through the whole growing period. Flowers bloomed just after every full blooming period showed lower value of pod/flower ratio and higher pod/flower ratio was obtained from flowers bloomed before or far after full blooming at plots seeded May 10 and June 9 in three pulse crops. Most full blooming period of soybean coincided within 5 days near the terminal leaf appearance date, and number of flowers bloomed before terminal leaf expansion and matured pods from these flowers were major in every soybean plant at all growing codition plots. No relations were found between terminal leaf appearance and flowering or pod setting patterns of azuki-bean and mungbean.

• Korean Journal of Environmental Biology
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• v.34 no.2
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• pp.63-72
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• 2016

The objective of this study was to identify the life form characteristics, naturalized degree and introduction period of naturalized plants on upland fields in South Korea. The survey sites were selected in 222 upland fields over 9 provinces where are relatively dry soil conditions and are disturbed continuously by farming practices. It seemed that these uplands maintain good condition for the invasion and settlement of alien plants. Field surveys were carried out twice from May to June and from August to September in 2013. The vascular plants of the upland fields were listed into 539 taxa which contain 103 families, 320 genera, 448 species, 2 subspecies, 74 varieties and 15 forms. Ninety nine taxa were naturalized plants composed of 23 families, 64 genera, 91 species and 8 varieties. The urbanization index and naturalized index is 30.65% and 18.37%, respectively. Among total 99 naturalized plants, Compositae (30 taxa) was the most dominant family, and followed by Gramineae (14 taxa). On the basis of dormancy form, 78 taxa were belong to Th (Therophyte). In radicoid form, $R_5$ plants (86 taxa) and $R_3$ plants (14 taxa) were dominantly distributed. In disseminule form, $D_4$ including 63 taxa and $D_2$ containing 26 taxa were dominant. On the basis of growth form, erect form (e) containing 26 taxa was dominant. In conclusion, life form spectrum was $Th-R_5-D_4-e$ type. According to life form analysis, naturalized degree and introduction period, alien plants with unique characteristics may have high ability to settle and spread nationwide after inflow into South Korea. It needs further to observe some plant species with or without ecological features such as widely disseminated seeds by wind or water, high seed productivity, long life-span seeds, high germination rate of seeds, or non-dormant germinable seed.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.1
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• pp.84-91
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• 1983

These experiment were conducted to investigate the seasonal changes of nodule formation and $N_2$-fixing activitues of soybean root nodules which grown in pot on five cultivars in different soils. The results obtained were as follows; 1. It was found that the development of nodules starts from 20 days after planting and continues to increase up to 50-60 days after planting. 2. $N_2$-fixing activities were different with cultivars of soybean. The trend was high in order H-25 > Suweon 63 > Hill > Yugwoo 3# > Gwanggyo 3. Rhizobium japonicum isolated from different soybean cultivars showed different acetylene reducing activities in vitro ; high in order A62-1 > Suweon 63 > Hill > Gwanggyo > Yugwoo 3#.

• Korean journal of food and cookery science
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• v.21 no.1 s.85
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• pp.84-93
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• 2005

The antibacterial activities of methanol extract and systematic solvent fractions( -hexane, chloroform, ethyl acetate, and butanol) from Korean common type figs at different ripening stages were tested by the broth dilution method against 8 representative food-poisoning bacteria- : L. monocytogenes, S. aureus, S. enteritidis, E. coli O157:H7, E. coli, Y. enterocolitica, V. parahaemolyticus, and S. typhimurium. The methanol extracts of unripened I and II showed stronger activity than that of the ripened figs especially against L. monocytogenes, S. enteritidis, E. coli O157:H7, Y. parahaemolyticus and S. typhimurium in 10 mg/mL. The systematic solvent fractions showed stronger antibacterial activities than the methanol extract, even al the lower concentrations. The hexane fraction of ripened figs showed higher growth inhibition than those of unripened I and II against L. monocytogenes, E. coli O157:H7, Y. enterocolitica and V. parahaemolyticus. The chloroform fraction showed strong antibacterial activity in all ripening stages against E. coli O157:H7 and V. parahaemolyticus. The butanol fraction showed better inhibition activity in unripened I and II than in the ripened figs. The hexane and chloroform fractions showed inhibition activity of more than $75\%$ against E. coli O157:H7, V. parahaemolyticus in 0.5 mg/mL. Each fraction showed a little different antibacterial activity according to the ripening stages of the fruits and the tested strains. Especially, figs in the unripened II stage revealed superior activity relatively and the hexane and chloroform fractions revealed the strongest activity, followed by the butanol fraction, while the ethylacetate and water fractions hardly showed any activity.

• Journal of Bio-Environment Control
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• v.26 no.3
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• pp.201-207
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• 2017

Objective of this research was to investigate the influence of pre-plant nitrogen levels in root media on plug seedling growth of radish cv. Soksungbommu. To achieve the research purpose, a root medium, the mixture of perlite, coir dust, and peatmoss (volume percentage of 30:35:35) was formulated and the N levels incorporated during mixing were controlled to 0, 100, 250, 500, 750, 1,000, and $1,500mg{\cdot}L^{-1}$. Then, the seeds were sown into 72-cell plug trays in which the root medium was packed. The measurements of growth and analysis of tissue and root media were conducted 2 and 4 weeks after sowing. Elevation of pre-plant N levels raised EC and turned down pH of root media. But, as seedling grew, the pH rose and EC get lowered in all treatments. The EC as well as $NH_4-N$ and $NO_3-N$ concentrations of root media declined gradually until week 2, but those declined sharply between weeks 2 to 4. The seedling growth 2 weeks after sowing showed quadratic response to pre-plant N levels with the highest growth in $250mg{\cdot}L^{-1}$ treatment and lagging growth in the treatments of lower or higher N levels than $250mg{\cdot}L^{-1}$. The seedling growth 4 weeks after sowing showed also quadratic response with the highest growth in $500mg{\cdot}L^{-1}$ treatment. The tissue N contents were get higher and those of K, Ca, and Mg were get lower as pre-plant N levels were elevated. Above results suggest that lower than $250mg{\cdot}L^{-1}$ in pre-plant N levels is optimistic for growth of plug seedling and avoidance of toxic injury in very young stage.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.7 no.3
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• pp.105-114
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• 1974

Identification and change of microflora during the fermentation of anchovy Engraulis japonica, under the halophilic circumstance were investigated. The change of salinity and pH in meat and juice which decide the environment for microorganism and decomposition of nitrogenous compound which functions as a nutrient source were also discussed by measuring the content of total-N, amino-N, nonprotein-N, TMA and VBN, The fresh anchovy was mixed with rock salt (20 percent w/w) and stocked for six months. Through the fermentation lag phase of viable cells extended for 20 days that was obviously larger compared with other circumstances, hereafter increased to reach the maximum value of $5\times10^4$ total count per gram at 35 day stock. The stationary phase proceeded for 25 days. 540 strains were isolated and among them 11 genus of bacteria, 3 genus of yeasts, were identified and other 2 yeast strains of unidentified. At the initial stage of fermentation, Pseudomonas, and Helobacterium prevalently grew, at the middle stage, they disappeared rapidly and Pediococcus and yeasts completely dominated, where they are assumed to get directly involved with fermentation of fish, The PH value tended to decrease in the progress of fermentation and at 100 day stock it showed the minimum value of 5.5 to 5.6 in both meat and juice. The highest salinity of meat decreased to 18 percent, while in juice it decreased to 28 percent since 50 days stock. The content of total-N in meat gradually decreased to 2.8 percent, while in juice it increased to 2.3 percent at 100 day stock, However nonprotein-N was 1.8 percent and amino-N was 1.1 Percent. Since 100 days stock, the increasing rate of amino-M is too low it could be judged to entered the final stage of fermentation, In the first 20 days stock, the increase of VBN and TMA can be explained by the growth of putrefactive bacteria such as pseudomonas on the meat before salts penetrate into the fish meat, while reincrement after 100 days stock, is explained by decomposition of free amino acid due to the reactions of bacteria and enzymes.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.5
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• pp.81-87
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• 2014

Heavy metal pollution is a widespread global problem causing serious environmental concern. Heavy metals such as Cd, Pb, and Zn can induce toxicity in all organisms if the soil levels of contaminants reach critical values. The aim of the present study was to examine the application of Liriope platyphylla, an ornamental Korean native plant with great potential for contaminated soil in urban areas, to determine tolerance for Cd, Pb, and Zn. Plants were grown in amended artificial soil with Cd, Pb, and Zn at 0, 100, 250, and $500mg{\cdot}kg^{-1}$ for 7 months. The length of leaf, width of leaf, total leaf number, dead leaf number, new leaf number, chlorophyll contents, and ornamental value were monitored from May to August, during growth the period. The relative leaf length and leaf width displayed rapidly decreasing tendencies with an increasing Cd concentration beginning from 4 months after planting. The same decreasing tendency was observed in total leaf number, new leaf number, chlorophyll contents, and ornamental values showed a trend of Control> $Cd_{100}$ > $Cd_{250}$ > $Cd_{500}$. In Pb concentration treatments, the relative leaf length and leaf width were significantly lower in plants grown at $250mg{\cdot}kg^{-1}$ and $500mg{\cdot}kg^{-1}$ as compared to the Control, $100mg{\cdot}kg^{-1}$. The total leaf number, new leaf number, and dead leaf number did not show significant difference among treatments in Control and $Pb_{100}$ but chlorophyll contents and ornamental value decreased with increasing Pb supply concentration treatments. However, in Zn supply treatments, the relative leaf length was higher at $100mg{\cdot}kg^{-1}$ than the Control, $250mg{\cdot}kg^{-1}$, $500mg{\cdot}kg^{-1}$, but the relative leaf width decreased compared to the Control, $Zn_{100}$, $Zn_{250}$, and $Zn_{500}$. The total leaf number, dead leaf number, new leaf number, and ornamental value showed the lowest value in plants grown in $Zn_{500}$ treatment but no significant differences were found among other treatments.