• Korean Journal of Organic Agriculture
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• v.20 no.3
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• pp.345-356
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• 2012

We conducted a survey of actual using conditions of farm-made liquid fertilizers by investigating their formulation types, materials, making processes, using methods and various beneficial effects on 29 farms certified by National Agricultural Products Quality Management Service to produce environment-friendly agricultural products in 2009. Most of the materials used to make liquid fertilizers are those that can be easily obtained around the farms. Molasses or black sugar are added as an energy source of microorganism. And leaf mold, bacterial cultures supplied by agricultural extension centers of local governments, and cultures of native microorganisms were used as microbial sources for fermenting effective microorganisms. Types of the farm-made liquid fertilizers were fermented liquid fertilizers, fermented plant juices, amino acid liquid fertilizers, calcium-liquid fertilizers, and phosphoric acid liquid fertilizers. Effects of liquid fertilizers used by the farms were found to promote plant growth by supplying nutrition, to accelerate blooming and flower bud formation, to enhance the quality of agricultural products such as increase of sugar contents and improvement of storing conditions, to induce resistance against diseases and insect pests, and to cause endurance to high temperature stress. Chemical properties of the liquid fertilizers collected were analyzed. As a result, pH and EC range showed differences according to kinds of the liquid fertilizers. Amount of macro-nutrients, such as nitrogen and phosphoric acid, in most of the collected liquid fertilizers, was found to be low. Even though the liquid fertilizers were made from same materials, their contents was found to be different depending on the making process.

• Korean Journal of Organic Agriculture
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• v.20 no.1
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• pp.71-80
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• 2012

This experiments was conducted to investigate the influence on growth of rye, triticale with legume and investigated their productivity, feed value and stock carrying capacity in order to select the appropriate forage species in the central region of Korea. In the results, Rye+Red clover showed 5.2ton/ha of dry matter yield. But there was no significant difference with Triticale+Red clover and Rye in upland field. In paddy field, Rye+Hairy vetch showed 5.2ton/ha, but there was no significant difference with Triticale+Hairy vetch and Rye. Mixture effects with Rye, Triticale and Red clover, Hairy vetch by relative yield were more than 1.00 compared to monoculture, and their mixture effect was recognized in upland and paddy field. Relative feed value was highest in the applications of Triticale mixture in upland and paddy field. The average value of $K_{CP}$ and $K_{TDN}$ showed the highest one as 2.75head/ha/yr in Rye+Red clover in upland field and 2.84head/ ha/yr in Triticale+Hairy vetch in paddy field. According to the results, Rye+Red clover in upland field and Triticale+Hairy vetch in paddy field were considered to be the most appropriate winter forage crops for the central region of Korea in terms of productivity, feed value and stock carrying capacity.

• Korean Journal of Organic Agriculture
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• v.20 no.1
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• pp.59-70
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• 2012

This experiments was conducted to investigate the influence on the growth of Sorghum ${\times}$ Sudangrass hybrid by use of various organic fertilizer and investigated their productivity, feed value and stock carrying capacity. In the results, the application of fermented poultry manure showed 93.6ton/ha, 19.6ton/ha, 1.12ton/ha, 11.31ton/ha of fresh yield, dry matter yield, crude protein (CP) yield and total digestible nutrients (TDN) yield but there were no significant differences with the application of poultry by-product compost (poultry manure with sawdust) and swine by-product compost (swine manure with sawdust). And the average value of $K_{CP}$ and $K_{TDN}$ showed the highest one as 9.45head/ha/yr in the application of fermented poultry manure. However, organic matter content of fermented poultry manure to the lower portion of 32.1% compared to other organic fertilizers could imagine that mineralization of fermented poultry manure was fairly advanced and plant used most of nitrogen in fermented poultry manure, so productivity of Sorghum ${\times}$ Sudangrass hybrid was shown more than other organic fertilizers. If other organic fertilizers use continuous, this difference can be considered to be reduced further. As a result, fermented poultry manure is better than other organic fertilizers in productivity, feed value and stock carrying capacity due to the higher content of mineralizable matters. In addition, mixing poultry manure with cow and swine manure is better choice because cow and swine manure will meet a low organic matter in poultry manure.

• Korean Journal of Organic Agriculture
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• v.20 no.1
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• pp.37-48
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• 2012

This study was conducted to evaluate the effects of ground cover treatments on the nutrient contribution in a 'Niitaka' pear ($Pyrus$ $pyriforia$) orchard. Treatments included; 1) sod culture, 2) winter cover crop [ryegrass+hairy vetch], and 3) winter [ryegrass+hairy vetch]+summer [greensolgo (sudan grass ($Sorghum$ $bicolor$ L.))+ nemajanghwang (crotalaria ($Crotalaria$ $juncea$ L.)] cover crops. Ryegrass and hairyvetch were seeded with 6.4 kg/10a and 3.0 kg/10a, respectively, on October 17 of 2008, and greensolgo and nemajanghwang were seeded with 2.0 kg/10a and 3.0 kg/10a, respectively, on June 4 of 2009 at a diligent farmer in Boseong in Chonnam. Winter+summer cover crops provided greater amounts of dry weight, followed by winter cover crop and sod culture. The difference of amounts of dry weight from the ground covers affected to the levels of total N, P, and K contents, which were greater nutrient levels than those of recommended nutrient requirement for satisfying 10- to 12-year-old pear tree growth. Greater amounts of dry weight from the ground covers increased organic matter and concentrations of K and Mg in soil. Foliar nutrient concentrations, as an indicator of nutrient status of a tree, were not affected by application of ground cover treatments.

• Korean Journal of Organic Agriculture
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• v.20 no.3
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• pp.357-368
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• 2012

This study was conducted to evaluate soil inorganic N concentrations and N uptake efficiency of sorghum ${\times}$ sudangrass hybrid (Sorghum bicolor (L.) Moench) as affected by organic nutrient sources from 2009 to 2011. The treatments included chemical fertilizer, compost, oilcake, alfalfa hay mulch, and control. Nutrient applications were made at rates equivalent to approximately 210 kg of actual N per hectare. The precipitation during the growth period from May to September was higher in 2011, followed by 2009, and 2010. Oilcake had the lowest C:N ratio in the raw materials. Compost treatment slowed N-mineralization rate in soil during the measured years. Soil mineral nutrition and dry matter production were not consistently affected by treatments, but the dry matter production was negatively correlated with the amount of precipitation from May to September for three years. Chemical fertilizer treatment increased N efficiency in plants in the first two years, observing with lower N efficiency in plants treated with compost for 3 years. Increased precipitation from June to August improved N efficiency in sudangrass plants treated with compost but reduced the efficiency with the chemical fertilizer. Total dry matter production and N efficiency in plants were not affected by the C:N ratio of the raw materials rather than weather condition.

• Korean Journal of Organic Agriculture
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• v.21 no.3
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• pp.437-450
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• 2013

Miscanthus sacchariflorus var. No. 1 has been newly developed in Korea. This study was conducted to assess the feed value of M. sacchariflorus var. No. 1 at different growth and harvesting time. Total 3 different miscanthus - 1y4m (first shoot and harvested at 4 month), 2y4m (second shoot and harvested at 4 month) and 2y8m (second shoot and harvested at 8 month). Two experiments were carried out, In vitro rumen simulated fermentation and In situ dry matter digestibility (DMD). Ruminal pH at in vitro fermentation were higher in M. sacchariflorus var. No. 1 treatments compared to the rice straw (RS). In volatile fatty acid production, 1y4m resulted in higher acetate production than the other M. sacchariflorus var. No. 1 at higher maturity stages. Significant differences among treatments were observed in propionate and total volatile fatty acid (VFA) productions at 9, 24 and 48 h of incubation times. Higher ammonia nitrogen productions were found as increased maturity of M. sacchariflorus var. No. 1. At In situ experiment, high DMD was detected in the order of RS (60.51%) > 1y4m (57.65%) > 2y4m (57.63%) > 2y8m (46.28%). The results from this study indicate that young and early harvested M. sacchariflorus var. No. 1 are able to improve its nutrient values in the ruminant animal.

• Korean Journal of Organic Agriculture
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• v.21 no.3
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• pp.413-422
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• 2013

This experiment was conducted to clarify the effect of double layer mulching on reducing the labor required to weed control and Leaf sheath training of the garlic cultivation. Six mulching methods(non-mulching, transparent P.E., rice hull+transparent P.E., sawdust+transparent P.E., rice straw+transparent P.E., black P.E. film+ transparent P.E.) were used for the experiment, and transparent P.E film was removed on April 10. Weed occurrence was in the order of black P.E. film< transparent P.E

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.4
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• pp.280-286
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• 2007

In order to find out the effects of the anticyclonic eddy on the distribution of nutrients and chlorophyll concentrations in the Ulleung Basin during spring and summer, we measured temperature, salinity, nutrients, and chlorophyll from the surface to 200 m water depth at five stations in July 2005 and April 2006. In spring, surface mixed layer was very deep inside the eddy, about 200 m, but it was relatively shallow outside the eddy, about $20{\sim}60$ m. Inside of the eddy, nutrients in the surface waters were sufficient by supply from the deep layer, whereas outside of the eddy, they were fairly depleted due to the stratification in the surface layer. In spring, chlorophyll concentrations were relatively low inside of the eddy due to the deeper surface mixed layer compared with the euphotic depth, and the depth-integrated chlorophyll concentrations outside of the eddy were twice as much as those inside of the eddy. In summer, nutrients in the surface waters were completely depleted at all stations due to the well stratification in the surface layer. The typical distribution pattern of subsurface chlorophyll maximum was observed at all stations, and the depth-integrated chlorophyll concentrations inside of the eddy were almost twice as much as those outside of the eddy. The anticyclonic eddy appearing in the Ulleung Basin every year significantly affects the phytoplankton biomass, with the opposing effects in spring and summer; in spring, the anticyclonic eddy suppresses phytoplankton growth, but in summer, it enhances the phytoplankton biomass.

• Journal of the Korean Vacuum Society
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• v.18 no.5
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• pp.358-364
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• 2009

We investigated the growth of ZnO thin films with prominent emission characteristics through minimizing the formation of defects by using pulsed laser deposition (PLD). To do so, the ZnO films were deposited on sapphire(0001) substrates at the substrate temperature of $400-850^{\circ}C$ and then the variation of their structural and optical properties were analyzed by x-ray diffraction, atomic force microscope and photoluminescence. As a result, all ZnO films were grown with c-axis preferential orientation irrespective of the substrate temperature. However, the crystallinity and stress state were dependent on the substrate temperature and the ZnO film deposited at $600^{\circ}C$ showed the best surface morphology and crystallinity with nearly no strain. And also this film exhibited outstanding emission characteristics from the viewpoint of full width half maximum of UV emission peak as well as visible emission due to defects. These results indicate that the emission characteristics of the ZnO films are strongly related to their structural characteristics influenced by substrate temperature. Consequently, ZnO films with strong UV emission and nearly no visible emission, which are applicable to UV emission devices, could be grown at the substrate temperature of $600^{\circ}C$ by PLD.

• Journal of the Korean Vacuum Society
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• v.18 no.5
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• pp.352-357
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• 2009

The InAs multi-quantum dots (MQDs) solar cell and InGaAs multi-quantum wells (MQWs) solar cell to cover 1.1 eV and 1.3 eV were designed by 1D poisson, respectively. The MQDs and MQWs of 5, 10, 15 layers were grown by molecular beam epitaxy. The photo luminescence results showed that the 5 period stacked MQDs have the highest intensity at around 1.1 eV with 57.6 meV full width at half maximum (FWHM). Also we can observe 10 period stacked MQWs peak position which has highest intensity at 1.31 eV with 12.37 meV FWHM. The density and size of QDs were observed by reflection high energy electron diffraction pattern and atomic force microscope. Futhermore, AlGaAs/GaAs sandwiched tunnel junctions were modified according to the width of GaAs layer on p-type GaAs substrates. The structures with GaAs width of 30 nm and 50 nm have backward diode characteristics. In contrast, tunnel diode characteristics were observed in the 20 nm of that of sample.