• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.3
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• pp.204-212
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• 2019

The optimal application rate of a controlled release fertilizer (CRF) on the growth, yield, and seeding time of rice grown on seedling trays was investigated. The experimental field was located at $37^{\circ}22^{\prime}10^{{\prime}{\prime}}N$ latitude and $127^{\circ}03^{\prime}85^{{\prime}{\prime}}E$ longitude in Hwaseong, Gyeonggi-do, Republic of Korea. The soil in the paddy field was a clay loam. The CRF used in the experiment contained $300g\;kg^{-1}$ of nitrogen, $60g\;kg^{-1}$ of phosphate, and $60g\;kg^{-1}$ of potassium, respectively. The CRF was applied at the rate of 0, 200, 300, 400, 500, and 600 grams on rice seedling tray compared with the field application based on soil testing (control), respectively. The CRF can be applied as single application(which can replace basal fertilizer application and two top dressing application) directly to the seedling tray, and showed the minimum release at the seedling period. Considering the plant growth, nitrogen use efficency and yield of rice, the optimal application rate of developed CRF was 500 g per seedling tray and the yield of rice at this application rate was $4.92{\sim}5.04Mg\;ha^{-1}$. The regression formula between the rice yield and application rates of CRF was as follows ; "$Y=0.0002{\chi}^2+0.0963{\chi}+411.6$($R^2$ : 0.9922) in 2010 and $Y=8E-6{\chi}^2+0.2723{\chi}+344.04$($R^2$:0.9864) in 2011, Y : Rice yield ($Mg\;ha^{-1}$), ${\chi}$ : Application rate (grams) of controlled release fertilizer". The optimum application rates of CRF per rice seedling tray by regression formula was 498 grams in 2010 and 513 grams in 2011.

• Korean Journal of Plant Resources
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• v.9 no.2
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• pp.157-163
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• 1996

This study was carried out to control the decrease of yield and the deterioration of quality of Angelica gigas roots by bolting. This phenomenon resulted from lignificartion and dwarfishness of roots because of bolting formed for inflorescence and fruition. Seedlings were grown for 60,90 and 120 days in nursery of the green house, and transplanted in main field to compare with traditional seedling that grew for 1 year. Growth of the petiole length compare with length and leaf width of aerial parts in nursery showed a remarkably progress, and root characters as root length, root diameter and root weight grew more vigorously in the order of nursery periods. Bolting was not entirely formed in plots transplanted the seedlings which grown for short-time; 60, 90 and 120days, but showed the high bolting rate, 64.3%,in traditional seedling plots. Yield was higher in plots that transplanted short-time growing seedlings than that transplanted traditional seedlings, and among 3 kinds of nursery periods yields were high in the order of nursery periods. For the increase of yield and decrease of bolting rate, it was needed to transplant small seedlings of 3-4g/plant which grew in nursery for 90-120 days.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.3
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• pp.326-332
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• 2011

The authors examined the effects of operating parameters on the $H_2$ production by dark fermentation of the wastewater generated from food waste recycling facilities, in short "food waste wastewater (FWW)". Central composite design based response surface methodology was applied to analyze the effect of initial pH (5.5-8.5) and substrate concentration (2-20 g Carbo. COD/L) on $H_2$ production. The experiment was conducted under mesophilic ($35^{\circ}C$) condition and a heat-treated ($90^{\circ}C$ for 20min)anaerobic digester sludge was used as a seeding source. Although there was a little difference in carbohydrate removal, $H_2$ yield was largely affected by the experimental conditions, from 0.38 to 1.77 mol $H_2$/mol $hexose_{added}$. By applying regression analysis, $H_2$ yield was well fitted based on the coded value to a second order polynomial equation (p = 0.0243): Y = $1.78-0.17X_1+0.30X_2+0.37X_1X_2-0.29X_1{^2}-0.35X_2{^2}$, where $X_1$, $X_2$, and Y are pH, substrate concentration (g Carbo. COD/L), and hydrogen yield (mol $H_2$/mol $hexose_{added}$), respectively. The 2-D response surface clearly showed a high inter-dependency between initial pH and substrate concentration, and the role of these two factors was to control the pH during fermentation. According to the statistical optimization, the optimum condition of initial pH and substrate concentration were 7.0 and 13.4 g Carbo. COD/L, respectively, under which predicted $H_2$ yield was 1.84 mol $H_2$/mol $hexose_{added}$. Microbial analysis using 16S rRNA PCR-DGGE showed that $Clostridium$ sp. such as $Clostridium$ $perfringens$, $Clostridium$ $sticklandii$, and $Clostridium$ $bifermentans$ were main $H_2$-producers.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.4
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• pp.70-82
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• 2007

Aiming at nature's early restoring needs to select plant species harmonizing with surrounding environment that fits to restoring goal of ultimately aiming at woody plants dominant vegetation that protect and stabilize surface parts of bared slopes. And it is important to make it assimilated with surrounding natural vegetation by differentiating planning of seed mixtures. Natural Ecological Restoring Construction Methods (JSB Method) was developed to increase the effect of landscape change according to seasons not to simple hydro-seeding by reducing rate of foreign grasses while raising rate of wild flower using. It was considered that using wild flowers that bloom on each season solved the problems of slope landscapes that looks artificial and uninteresting. After researching environmental condition of the slopes, JSB Method has shown that, as of wet-type method, soil is relatively soft and the difference of thickness of plant base soil media affects on the difference of soil hardness. In case of soil hardness of 8.8~17mm, there's dangerousness of slope's collapsing, but it has shown that growth of plant was favorable. For the acidity of soil, most of them are in the type of neutralized soil of more than pH 6. And after analyzing the degree of woody plants dominance, it had shown that lower part was occupied with wild flowers and other herbaceous species like China pin, golden phesant mum, pitcher plant, and middle and upper part was occupied with woody plants like silk-tree, sumac forming multi-layer structure. It can be concluded that the restoration objects of the woody plant vegetation on the roadside slopes can be accomplished successfully by Natural Ecological Restoring Construction Method (JSB method).

• Korean Journal of Environmental Agriculture
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• v.32 no.4
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• pp.268-272
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• 2013

BACKGROUND: The mixtures of legumes and non legumes can be an efficient tool to combine the benefit of the single species in the cover crop practice. However, there is a lack of information on how the species proportion may affect N accumulation and how this can influence the nitrogen use of subsequent rice production. METHODS AND RESULTS: In this study barley and hairy vetch was selected as a green manure. The pure stands or mixtures with different seeding ratios was tested on green manure N accumulation and its following rice cultivation. Total aboveground biomass and N accumulation of mixture were higher compared to that of pure barley and hairy vetch. Among the mixtures, the highest aboveground biomass (8.07 Mg/ha) and N accumulation (131 kg/ha) was observed in B75H25 (barley 75% + hairy vetch 25%). The N accumulation of the mixture ranged from 99 kg/ha to 131 kg/ha which was much higher than amount of recommended (90 kg/ha) for rice. All mixture (barley 75%+hairy vetch 25%, barley 50%+hairy vetch 50%, barley 25%+hairy vetch 50%) produced 7-8% more rice yield than the conventional cultivation (NPK). The rice yield of in barley monocrop was 4% less than that of NPK. COLCLUSION(S): Adopting mixtures of barley and hairy vetch could be efficient strategy for rice production as an alternative of nitrogen fertilizer.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.4
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• pp.393-398
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• 2013

Lodging in the direct seeded rice cultivation on flooded paddy is being severe problem due to the lower production and grain quality at ripening stage. This study was conducted to examine the effect of Iprobenfos-metconazole (IPM) treated 50, 40 and 30 days before heading respectively as a plant regulator to reduce the lodging at ripening stage of direct seeding rice cultivation. The culm length treated with IPM, especially the 4th culm internode, was shortened more than with untreated plot, and the most effective time was at 30 days before heading. At 20 days after heading the flag leaves colour showed more greening than in the untreated leaves and the plot with IPM treatment was to be maintained longer compared to the control plot. The Nitrogen concentration of leaves with IPM was lower than in the control plot, and $SiO_2$ contents were higher than in the untreated plot and $SiO_2/N$ ratio was increased more in the IPM plot than in the control plot. The breaking strength of 3rd and 4th culm internode with IPM treatment was higher than in the untreated plot, and the lodging index was reduced in the IPM plot significantly and the field lodging also was reduced. As the results the rice production in the IPM plot was increased more due to be higher ripening ratio and seed grain weight compared to the untreated plot to be occurred the field lodging.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.1
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• pp.31-40
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• 1999

This study was conducted to investigate the effects of rhizosphere bacterium and pathogenic fungi on the growth of corn(Zea may L.) in continuous corn cultivation soil(CCCS) and non-continuous cultivation soil(NCCS). Corn was established by seeding into pots of 30 cm in diameter and 50 cm in depth containing 1 : 1 mixture of soil and vermiculite. Rhizobacterium and pathogenic fungi were inoculated into the soils. The field experiment was carried out at the Animal Research Station, College of Agriculture, Chonnam National University. Sample of corn was taken from each pot at 50 days and 90 days after sowing. Corn was cultivated in a vinyl house with three replications under natural daylight conditions. The bacterium used in this study was Bacillus subtilis. B. subtilis was directly isolated and identified from forage rhizosphere soil. Dry matter(DM) of coron plant in treatment without B. subtilis was lower than that in treatment of B. subtilis. DM of corn plant inoculated with B. subtilis was higher than that of corn inoculated with pathogenic fungi in both CCCS and NCCS. DM of corn plant in NCCS was more increased than that in CCCS. The effect of B. subtilis inoculation on the growth of corn was better in NCCS than in CCCS. However, DM of corn plant was apparently decreased by the inoculation of the pathogenic fungi in both CCCS and NCCS.

• Korean Journal of Plant Resources
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• v.10 no.1
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• pp.17-23
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• 1997

This experiment was conducted to investigate the effect of planting date and planting density on the growth and yield characters of yacon (Polymnia sonchifolia POEPP) and to establish cultivation method in the middle region of Korea. An introduced variety of yacon was used. Seeding dates were from April 5 to April 7,and seedlings were trasplanted three times on the May 25, june 5, and June 15 with the intervals of 10 days. Planting densities were 80(width) $\times$ 35(distance) cm, 80 $\times$ 45cm, and 80 $\times$ 55cm. Plant height was not significant among planting dates, but was longer in the order of 80 $\times$ 55cm, 80 $\times$ 35cm, and 80 $\times$ 35cm among planting densities. Fresh weight of top part was heavier as the planting dates were faster and planting densities were narrower. Total yeid of tuber had no significant among planting dates and was higher in the density with 80 $\times$ 45cm and had the same tendency in the yeild of commercial goods. Correlation coefficient between plant height and yeild of commercial goods was highly positive(r= 0.927**).

• Journal of Korean Society of Forest Science
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• v.84 no.4
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• pp.495-501
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• 1995

Betula pendula and B. platyphylla var. japonica seedlings and/or grafts growing inside and outside of a plastic-greenhouse were treated with growth regulators to induce flowering at early stages of seedling and graft developments. The seedlings began to develop female catkins visibly in eight to nine months after seeding and in five months after the first treatment of growth regulators. Thirty three percents of the seedlings grown under controlled environment in the plastic-greenhouse with sufficient nutrient supply developed female catkins both in control plants and in the plants treated with IAA, $GA_3$ and kinetin, while none on the control plants grown in the field showed any sign of the development of floral organs. Sixty seven percents of the seedlings treated with ABA and SADH grown in the Plastic-greenhouse developed female catkins. All the seedlings treated with 6.24 mM of SADH developed female catkins. SADH treatment to 2-5 year old seedlings and grafts of birch had a tendency of positive effect on inducing and increasing the flowering of the two birch species.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.3
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• pp.248-253
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• 1990

Germination and seedling growth of chinese milkyetch (Astragalus sinicus L. Line A) seeds were measured at four temperatures (15. 25. 30, and 35$^{\circ}C$), three polyethylene glycol (PEG) 10.000 (MW) solutions (0, 20 and 25 g/100$m\ell$ H$_2$O), and five sulfuric acid treatments (conc, H$_2$SO$_4$: Seeds/weight base: 0, 1:1 10min.. 1:1 20min.. 1:1.5 10min. and 1:1.5 20min, immersion), Adjustments of PEG 10.000 solutions were based on water potentials of 0.0, -0,5 and -0.8 ㎫ at room temperature. Observations were taken at 7 days for each treatment combinations. Germination percent of chinese mikvetch seeds was the highest at 15$^{\circ}C$ and seeding length was the longest at 25$^{\circ}C$. Both germination percent and seedling length were rapidly decreased as PEG concentration increased from 0 to 25g/100$m\ell$ H$_2$O. The highest germination percent was found at PEG 20 and 25 of 15$^{\circ}C$ among those of four temperatures, Sulfuric acid treatments showed little effect on germination percent and seedling length compared to untreated control, However. in the case of PEG 0, greater germination perccent was obtained at the treatment of 1:1.5 for 10 minutes immersion, The result of this study-indicated that germination of chinese milkvetch seeds was affected mostly by moisture stress conditions.