• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.3
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• pp.285-294
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• 1994

Dried top and root extracts of seven different weed species, fresh top and root extracts, and various concentrations of extract (0, 5, 10 and 15%, W/V) and residue rate (0.0, 0.25. 0.5, 0.75 and 1.0%) of velvetleaf (Abutilon theophrasti Medic.) were used to study their allelopathic effects on alfalfa in the laboratory and greenhouse. Top and root aqueous extracts of common lambsquarter (Chenopodium album L.), giant foxtail (Setaria faberii Herrm), redroot pig-weed (Amaranthus retroflexus L), velvetleaf, large crabgrass (Digitaria sanguinalis L), canada thistle (Cirsium arvense L.) and prostrate knotweed (Polygonium aviculare L.) significantly inhibited germination, seedling length, weight, and vigor in alfalfa. Top growth extracts of weeds exhibited greater allelopathic effects than root extracts. Alfalfa test species, WL-320, responded significantly different to the various weed species extracts in terms of allelopathic effect. The regression slopes of various top extracts showed significant variation with respect to germination percentage. Velvetleaf (b=3.69) extracts were the most inhibitory, while large crabgrass (b=2.39) extracts had the least allelopathic effect on alfalfa. When compared the activity of fresh velvetleaf extract to that of dry velvetleaf extract, dry extract was more inhibitory to alfalfa germination and seedling growth. Germination, seedling length and weight of alfalfa were inversely proportional to the concentration of dried velvetleaf extracts. Seedling emergence and survival percentage was inhibited by velvetleaf residue mixture treatment. Also, more of the toxic effects were observed from the dried top extracts, as compared to extracts from fresh top and root. These results demonstrate the allelopathic activity of different weed species extracts and suggest that weeds may affect crop growth and development due to the inhibitory effects of allelochemicals present in weed tissue.

• Korean Journal of Medicinal Crop Science
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• v.11 no.5
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• pp.347-351
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• 2003

This experiment was carried out to study the optimal chilling period for breaking the physiological dormancy of dehisced E. senticosus seeds and to investigate the critical seeding date in Kangwondo. Storage at $5^{\circ}C$ for 85 days was most effective in breaking dormancy of dehisced seeds, but didn't germinated synchronously. Only 28.1% of undehisced seeds germinated after 125 days of low temperature storage. For improving seedling survival rate in the field, 50% shading was more effective than 30% shading. Delayed seeding date resulted in decreased seedling fresh weight, dry weight, leaf area and root length, but seeding date has no significant affecte on stem length.

• Journal of Biosystems Engineering
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• v.26 no.4
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• pp.379-384
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• 2001

To enhance the smooth graft-taking of grafted seedlings, the excessive evapotranspiration from grafted seedlings just after grafting should be avoided. A measurement system of the evapotranspiration rate of grafted seedling under artificial lighting was set up to investigate the effect of physical environment on the evapotranspiration and graft-taking characteristics of grafted seedlings quantitatively. The evapotranspiration rate of grafted seedlings affected by relative humidity and light intensity were analyzed using the measurement system. The hypocotyl of watermelons (Citrullus vulgaris cv. Sweetdew, Hungnong Seed Co.) was slantly cut and then inserted into a hole on the stem of rootstock (Lagenaria siceraria cv. FR-King, Hungnong Seed Co.). Grafted seedlings were healed and joined for 5 days under cool-white fluorescent lamps (FL20SEX-d/18, Keumho Electric Co.) with photoperiod of 12h$.$d$\^$-1/ except dark period for one day after grafting in a closed graft-taking enhancement system developed by Kim(2000). The evapotranspiration rate and graft-taking of grafted seedling at air temperature of 23$\^{C}$ and air current speed of 0.1m$.$s$\^$-1/ was highly affected by relative humidity. But light intensity showed higher effect on the stem length of scion than relative humidity. In conclusion, it was suggested that relative humidity should be controlled at higher than 90% with photosynthetic photon flux of 50$\mu$mol$.$m$^2$$.$s$\^$-1/ to increase the survival of grafted seedlings and to produce healthy seedlings.

• Journal of Aquaculture
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• v.12 no.1
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• pp.25-30
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• 1999

This study was carried out to produce the seedling of the larvae and juveniles of pale chup, Zacco platypus (Cyprinidae) in terms of artificial hatching, feeding behavior and growth rates. The total lengths of the newly hatched larvae were 7.6~8.2mm (mean: 7.97mm). The hatched larvae rose to the surface 3 days after hatching. The larvae were fed Daphnia, rotifer, Artemia and powdered feed. Hatching experiments were conducted in jar incubators under the different water temperature conditions, $20~32^{\circ}C$. The highest hatching rate was at $26^{\circ}C$ after 47 hours. Jar incubators was the highest hatching rate (89%), and cage and Californian incubators were useful and relatively high hatching rates (>89%). The size of the larvae 50 days after hatching were 30.0mm (25.6~32.0mm). As the water temperatures was increased, the growth rate of the larvae was also increased. Especially, the growth rates were favorable over $26^{\circ}C$, but survival was the worst at $32^{\circ}C$. This species was quick to accept assorted feed after hatching. The assorted feeds for flounder and rockfish better than that of carp in reference to growth rate.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.5
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• pp.514-520
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• 1996

To clarify the proper nitrogen application level for rasing rice infant seedling under different nursery soil, Dongjinbyeo was raised at seedling box with different basal nitrogen level. The results are as follows. The higher the nitrogen level was, the lower emergence rate and the lower establishment rate. The establishment rate was less than 90%, when the nitrogen was more than 2g/box in hill soil and more than 1g/box in paddy soil. The more the nitrogen level was, the higher the seedling height in hill soil, but was higher in the order of N-2, 3, 1 and 0g /box. Leaf number wasn't significantly different between nusery soils and among nitrogen levels when seedling was raised more than 6 days. The endosperm survival rate was decreased as the increased nitrogen level, but wasn't different between the nursery soils. Amount of root was decreased as the increased nitrogen level in paddy soil, but was heavier in the order of N-1, 0, 2 and 3g /box in hill soil. Mat formation was better as the nitrogen level was decreased in all nursery soils. Considering the emergence rate, seedling charactors and mat formation, the proper nitrogen levels seemed to be 2g /box for hill soil and 1g /box for paddy soil.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.2
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• pp.45-52
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• 2012

Enrichment planting is commonly used for increasing the density of tree species in secondary forests and one of forest rehabilitation programs in Lao PDR. This study aimed to determine the performance of five native species in enrichment planting using different canopy opening treatments, and to examine the suitable species and silviculture techniques applicable to a logged-over forest in Lao PDR. Results of the study showed that only crown height had significant difference among species and planting treatments. The survival rate and crown diameter were significantly different by species, but not by planting treatments. However, root collar diameter (RCD) and height of seedlings showed significant differences among planting treatments. Among the study species, Hopea odorata and Dalbergia cochinchinensis showed significantly higher survival rate and height growth, indicating their suitability in enrichment planting for rehabilitation of forest in Lao PDR. The results also suggested that 2 m width line planting stimulated RCD growth, but wider line planting, such as gap planting, promoted height growth of seedlings.

• Journal of Korean Society of Forest Science
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• v.103 no.4
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• pp.556-563
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• 2014

The purpose of this study was to evaluate the effects of container types on seedling growth of Chamaecyparis obtusa (2-year-old) in the container nursery culture. We used three container types [20 cavities (400 mL/cavity, $150seedlings/m^2$), 24 cavities (320 mL/cavity, $200seedlings/m^2$), and 35 cavities (240 mL/cavity, $260seedlings/m^2$)] and measured root collar diameter (RCD), height, biomass, root density and seedling quality index (SQI). The RCD, height, biomass, root density and SQI were the highest at 20 cavities/tray because this container has the largest volume and lowest seedling density. However, H/D and T/R ratio at all container types were not significantly different. The total biomass per unit area ($m^2$) were the lowest at 35 cavities/tray and those at both 20 and 24 cavities/tray were not significantly different. Container volume was positively correlated with RCD, height, biomass, root density and SQI except for H/D and T/R ratio, while seedling density negatively affected on them. Based on these results, 20 cavities/tray are optimal for container seedling production of C. obtusa. Usage of optimal container will make us get better quality seedlings and reduction of production costs in the container nursery as well as good field performances with higher survival rate in plantation.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.6
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• pp.87-96
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• 2010

This study was conducted to select environmentally-friendly and low-cost mulching material that could replace soil molding which can be used to restore vegetation in an abandoned coal mine area. To this end, we established 20 experimental plots (4m ${\times}$ 10m in size) on the steep, south west-facing slope of the abandoned coal mine area in Hwangji-Dong, Taebaek City, Gangwon Province in April 2006. We planted two-year-old 1,600 seedlings (at intervals of 0.6m ${\times}$ 0.8m) of drought-resistant tree species including Betula schmidtii, Betula platyphylla var. japonica, Amorpha fruticosa, and Quercus mongolica in the plots. After planting seedlings, mulching was applied by using five different kinds of material such as HWAP (Teracotem), peat moss, straw mats, wood chips, and control (no-mulching) and the effects of different mulching material on the survival rate and growth performance were compared. Three years after planting, the survival rate was the highest in wood chip mulching, followed by straw-mat, peat moss, HWAP, and control. The survival rate was the highest in Quercus mongolica, followed by Betula schmidtii, Betula platyphylla var. japonica, and Amorpha fruticosa. Meanwhile the height growth was the best in Betula platyphylla var. japonica, followed by Betula schmidtii, Quercus mongolica, and Amorpha fruticosa. The height growth of seedlings was the best in HWAP mulching, followed by peat moss, woody chips, straw mat, and control. From an economic point of view, wood chips are considered to be the best mulching material. The results showed that mulching without soil molding and/or mixing applications would be effective for restoring vegetation in an abandoned coal mine areas.

• Journal of Bio-Environment Control
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• v.29 no.3
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• pp.219-230
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• 2020

This study was conducted to determine the optimum medium and humidification period for the strawberry (Fragaria × ananassa Duch. cv. Maehyang) cutting seedling production. The cuttings were planted in coir (CO), rockwool (RW), phenolic foam (PF), and organic foam medium (OFM) with fogging treatment in 0, 3, 6, 9, or 12 days on February, 2019. And, as the field verification examination research, cuttings were planted in CO, RW, PF, and OFM, with misting treatment in 0, 6, 9, 12, or 15 days on June, 2019. In fogging treatments, rooting and survival rates of seedlings tended to increase with longer fogging periods, and rooting and survival rates were showed significantly higher in CO medium with more than 9 days of fogging periods. In misting treatments, rooting rate was significantly higher in CO and RW medium with more than 9 days of misting periods, and survival rate was significantly higher with more than 12 days of misting periods. There was no significantly difference by growth medium and humidification period in shoot and root growth. Therefore, when considering the rooting and survival rate the CO medium with 9 days of humidification period could be beneficial for the production of the 'Maehyang' strawberry cutting seedlings.

• Journal of Korean Society of Forest Science
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• v.95 no.6
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• pp.636-642
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• 2006

To make a new fairy ring of Tricholoma matsutake in situ, the way of production and transplanting of ectomycorrhizal seedlings of T. matsutake using Pinus densiflora was investigated after transplanting from 2000 to 2005 as well as the method to improve their survival rate for the fungus. For the production of ectomycorrhizal pine seedlings, the seedlings planted at the edge of fairy ring of T. matsutake in November showed 97% of the survival rate, while those planted in April showed 80% of the rate. For the complete infection of the T. matsutake, it required more than two years after planting. The infection rate of mycelia for the ectomycorrhizal seedlings was 17.6% when the natural seedlings were used, whereas it was relatively low when the seedlings prepared from the nursery were used. The survival of T. matsutake mycelium reached up to 22% by the transplanting in April, while the mycelium transplanted in October and November showed less than 5% of the survival. The survival of T. matsutake on the transplanted seedlings was the highest in the seedlings having 50% of infection rate before transplanting. Excavation of the ectomycorrhizal seedling to examine the vitality of ectomycorrhizal roots of T. matsutake resulted in the perishing of them. Therefore, the method using a 'rice bag triers' to check living mycelium of T. matsutake without digging of transplanted seedlings was introduced in this study. In addition, it is recommended that the examination has to be conducted at least two years after transplanting.