• Journal of Korean Society of Forest Science
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• v.99 no.1
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• pp.153-162
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• 2010

Abies holophylla Maxim. is a shade tolerant species that has potential to be used for continuous cover forestry system. Stand structure and natural regeneration of A. holophylla stands in Yong-In area located in the central part of Korea was investigated to estimate the self sustainability of A. holophylla plantation. Species composition, diameter at breast height (DBH) and height distribution of trees larger than 2 cm DBH were measured in ten stands in three study sites of Jeongsu-ri, Daedae-ri, and Hodong. Species and coverage of shrub layer, and A. holophylla seedlings were also investigated. While A. holophylla in non-managed stands (Jengsuri and Daedae-ri study sites) had the importance value of 40% and showed continuous diameter and age distribution, A. holophylla in Hodong site had narrow bell-shaped DBH distribution mostly concentrating between 25-35 cm DBH classes, and single canopy structure. Abies holophylla stands in Hodong have experienced occasional thinning and selective cutting. The correlation coefficient between age-DBH was significant but low ($R^2$=0.2, P=0.03), and similar aged A. holophylla had diverse DBH values. Continuos DBH distribution and multi-canopy structure of A. holophylla stands in Jeongsu-ri site show that natural regeneration of A. holophylla has been continuously occurred in this area. Seedling density of A. holophylla was between 2000 and 33000/ha, however, the number of trees in 2-5 cm DBH class was only 40-150 trees/ha, implying that the survival rate of seedlings is not high. Continuous natural regeneration and 0.6 cm/year of diameter growth rate of A. holophylla indicate that this area could be an appropriate habitat for this species, and A. holophylla plantation in this region seem to persist suggesting the possibility of managing the stands for continuous cover forestry system as well as selective harvesting practices.

• Journal of Bio-Environment Control
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• v.12 no.2
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• pp.68-71
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• 2003

Experiments were conducted to investigate optimal ionic salt strength in nutrient solution for small plug seedlings of ‘Nokgwang’ and ‘Kwari’ green pepper. Plant height increased with increasing ionic salt strength. total leaf area was 72％ greater in ‘Nokgwang’ and 18% greater in ‘Kwari’with 2.0 ionic salt strength than that with 1.0 strength. Dry weight per plant tended to increase at higher ionic salt strengths in ‘Kwari’, but to decrease in ‘Nokgwang’ Chlorophyll content increased with increasing ionic salt strength in both cultivars. Photosynthetic rate, stomatal conductance, and transpiration rate were higher for plants fertilized with 1.5 strength than other strengths in both cultivars. Photosynthetic rate peaked at 8.74 $\mu$mol$.$m$^{-2}$ s$^{-1}$ in ‘Nokgwang’ and 5.70 $\mu$mol$.$m$^{-2}$ s$^{-1}$ in‘Kwari’with 1.5 ionic salt strength.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.246-250
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• 2010

This study was conducted to find out the propagation method of a rare variety Daphne kiusiana Miq. in Korea through softwood cuttings. Daphne kiusiana Miq are the evergreen broad leaf tree which have lived in the southern part of Korea. The flowering time of Daphne kiusiana Miq is early spring and the flower has an attractive fragrance. Generally, plants are dioecious and only the male plants are found in Korea. Propagation by seed is very difficult in this tree. Softwood cuttings were taken to establish an efficient propagation method in Daphne kiusiana Miq Cuttings were grown in perlite:vermiculite (1 : 1), perlite, vermiculite, sand rooting media under shaded greenhouses during summer in 2007. The rooting rates of cuttings were 86.7%, 95%, 75% and 95% in perlite:vermiculite (1 : 1), perlite, vermiculite and sand media, respectively. Softwood cuttings taken on July and rooting at $27^{\circ}C$ were significantly improved the growth and rooting rates. Softwood cutting can be an effective means of propagation in Daphne kiusiana Miq.

• Journal of Bio-Environment Control
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• v.18 no.3
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• pp.273-279
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• 2009

This study was conducted to identify optimal concentrations of N (nitrogen) and K (Potassium) fertilizers on growth, yield and quality of melon (Cucumis melo. L) when they were grown with a fertigation culture in a greenhouse. Three strength (S) levels of fertilizers, including 1 S, 1/2S, and 1/4S were supplied N and K nutrients as using a trickle irrigation system. When the strength level of fertilizers was increased from 1/4S to 1 S, the level of EC (electronic conductivity) in soil was increased. Soil-water tension was ranged between -15 and -20kPa until fruit setting stage, whereas it was ranged between -45 and -50kPa in the later growth stages. In results, N fertilizer had effects on fruit yield and quality. A higher fruit yield was observed when plants were supplied with 1 S and 1/2S level of N fertilizer. The highest yield of marketable fruit, about 5,086kg/10a, was also observed when plants were supplied with 1/2S N fertilizer. A higher net index and sugar content of fruit was observed in the treatments of 1/2S and 1/4S level of N fertilizer compared to 1 S level. In contrast, there was no statistic difference in the yield and quality with three levels of K fertilizer. Results indicate that the 1/2S level for N and 1/4S level for K fertilizer are effective and optimal for the melon plants grown under the fertigation culture in terms of increasing fruit yield and quality and reducing the cost of fertilizers.

• Research in Plant Disease
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• v.17 no.2
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• pp.142-147
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• 2011

In order to develop a environmentally friendly control protocol for managing tomato leaf mold disease in the field, we employed bacteria- and fungi-based commercially available microbial preparations. The field experiment was conducted from April to July in 2010. Average incidence rates tomato leaf mold caused by Fulvia fulva were 13.1% at the two plastic houses located in Jangsung, Jeonnam area. Initially 11 microbial preparations were tested for antifungal activity against F. fulva in vitro. Among them, 7 selected preparations showed to be inhibited the mycelial growth of the fungal pathogen over 50%. Four microbes suppressed disease incidence as much 50% under greenhouse condition. Eventually in the field two microbial products including Bacillus subtilis GB-0365 and B. subtilis KB-401 respectively were showed control value up to 71.8% for four times sprays from 20 days to 70 days after transplanting. Furthermore, the control value of three times spray program demonstrated 79.3%. Efficacy of the three and four spray programs was more effective than that of non-spray control treatment. Our results indicated that adjustment of application method of commercially available microbial preparation could be used to control a target plant disease as an effective and efficient crop protection system for organic farming.

• Journal of Ginseng Research
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• v.32 no.4
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• pp.279-282
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• 2008

This study was conducted to compare the aerial parts growth, yield of fresh ginseng roots, quality of red ginseng roots, and photosynthesis (Fv/Fm, PSII) in leaves between non-irrigation plot and furrow irrigation plot during the ginseng growing seasons. The aerial part growth in furrow irrigation plot was higher than non-irrigation plot in all including the emergency rate, leafing rate and relatively growth rate. Root yield per 10a in irrigation plot was increased about 50% as compared with that of non-irrigation, also heaven and earth grade of red ginseng roots yield in irrigation plot was higher (40.3%) compared with that (30.6%) of non-irrigation plot in 6-years-old ginseng plant. Furrow irrigation markedly improved the ginseng quality and yield in comparison to non irrigation condition. Therefore it needs to control the soil moisture during the growing season for high yield and good qualities of ginseng roots.

• Korean Journal of Ecology and Environment
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• v.33 no.4 s.92
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• pp.387-394
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• 2000

Water pollution characteristics were investigated in the Kyongan stream and major inlet parts of Paltang Reservoir from April to July, 2000. Water quality in the Kyongan stream was extremly deteriorated by treated wastewater discharge at near sewage wastewater treatment plant (SWTP) located in the upstream, and it is likely to influence eutrophication of the lower part of the stream. Water quality of the Kyongan stream showed a typical hypertrophic condition. Influxed concentrations with $NH_4$ and SRP into the main stream from SWTP were declined precipitously as water flowed toward the lower part of the stream, and chlorophyll- a explosively increased in the midstream. Average concentrations of $NH_4$, SRP and chlorophyll-a in the main stream were $1,343\;{\mu}g\;N/l$, $1,779\;{\mu}g\;P/l$ and $188\;{\mu}g\;l$, respectively. Particularly, phosphorus load was very high, and its influence on the algal growth stimulation was remarkable. In comparison with the water quality inflowing into Paltang Resevoir, pollution status of the Kyongan stream was more worse than that in the Pukhan River and the Namhan River. The results of this study indicate that the management of point source, SWTP effluent, is urgent to mitigate eutrophication of Paltang Reservoir, and requires further necessary controls of inorganic phosphorus loading.

• Research in Plant Disease
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• v.12 no.3
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• pp.158-163
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• 2006

Sclerotinia rot caused by Sclerotinia sclerotiorum frequently causes serious and unpredicable yield losses of the leaves of perilla growing under structured cultivation as vegetable in Korea. Temperature for mycelial growth ranged from 5 to $30^{\circ}C$ with optimum temperature d $20^{\circ}C$. Sclerotia were formed fewer at low temperature, but their dry weight was heavier than that at high temperature. The apothecia were formed from the sclerotia that buried up to 3 cm soil depth at $15^{\circ}C$ in moisture condition. The incidence of perilla Sclerotinia rot caused by S. sclerotiorum was observed throughout the growing season at greenhouse. The occurrence of this disease was especially severe from January to February of low temperature period. The average incidence rates of this disease was up to 15%. The significant occurrence of this disease was showed mainly in the continuous cropping field for more than five years. The incidence of this disease increased according to the increase of continuous cropping year. The incidence rates of this disease reached up to 20% in the continuous cropping field for ten years. Also it was firstly investigated the natural infection caused by S. sclerotiorum on weed plants, Gnaphalium affine and Mazus pumilus in farmer's field. The casual fungus showed pathogenicity on 11 weed plants species tested, and more severe pathogenicity on G. affine, Latuca indica and Ixeris dentata included in the family Compositae. This result suggests that effective crop rotation and weed eradication can be the method for organic control of perilla sclerotinia rot, and sudden outbreaks of this disease on perilla growing under structure after paddy rice call be explained by the presence of weed hosts.

• Weed & Turfgrass Science
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• v.7 no.2
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• pp.111-119
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• 2018

This study was carried out to investigate the differences in germination and growth of Quamoclit coccinea Moench under various temperatures, seeding depths, and levels of shading and soil moisture for effective weed management. Seed dormancy of Q. coccinea Moench was over 1 year; best results were obtained when seeds were soaked in sulfuric acid for 15 minutes in order to break the dormancy. Germination rates of Q. coccinea Moench ranged from 69 to 73% at $25-35^{\circ}C$ and 26% at $15^{\circ}C$. The germination rates ranged from 70-84% at 2, 3, 5, 7, and 8 cm of seeding depths. In addition, the germination rates were 7% and 13% at 12 cm and 15 cm of seeding depths, respectively, and showed normal growth at the both seeding depths. Q. coccinea Moench showed a high germination rate regardless of shading levels, but shoot fresh weight varied depending on the level of shading as follows: 20%>no shading=shading 35%>shading 50%>shading 75%=shading 90%. Q. coccinea Moench did not germinate when soil had a saturation rate of either 30% or 100%. However, 60-83% of seeds germinated with optimal growth when soil had saturation rates of 60% and 80%.

• The Korean Journal of Ecology
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• v.27 no.2
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• pp.99-106
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• 2004

We developed the estimation model for the vegetation developmental processes on the severely burned slope areas after forest fire in the east coastal region, Korea. And we calculated the vegetation indices as a useful parameter for the development of land management technique in the burned area and suggested the changes of the vegetation indices after forest fire. In order to estimate the woody standing biomass in the burned area, allometric equations of the 17 woody species regenerated by sprouter were investigated. According to the our results, twenty year after forest fire need for the development to the normal forest formed by 4 stratum structure, tree, sub-tree, shrub and herb layer. The height of top vegetation layer, basal area and standing biomass of woody species show a tendency to increase linearly, and the ground vegetation coverage and litter layer show a tendency to increase logarithmically after forest fire. Among vegetation indices, Ive and Ivcd show a tendency to increase logarithmically, and Hcl and Hcdl show a tendency to increase linearly after forest fire. The spatial variation of the most vegetation factors was observed in the developmental stages less than the first 5 years which were estimated secondary disaster by soil erosion after forest fire. Among vegetation indices, Ivc and Ivcd were the good indices for the representation of the spatial heterogeneity in the earlier developmental stages, and Hcl and Hcdl were the useful indices for the long-term estimation of the vegetation development after forest fire.