• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.1
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• pp.50-56
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• 2016

Direct seeding of sorghum (Sorghum bicolor L. Moench) has a problem of low yield including poor establishment. This poor establishment results from poor quality seed, poor seedbed preparation, seedling pests, poor sowing technique and high soil temperature. This study sought to establish the age at which sorghum seedlings can be transplanted with minimal effects on grain yield. Transplants were raised in 128 nursery tray pot. Five seedling ages were established by transplanting at 10 (T10), 15 (T15), 20 (T20), 25 (T25) and 30 (T30) days after planting (DAP). The treatment combinations were arranged in a randomized complete block design and replicated three times with an individual plot size of $6{\times}5m^2$. Each plot had five ridges with a planting space of $0.60{\times}0.20m^2$ at one plants per stand. Results showed that seedling age on transplanting significantly affected growths and yields to sorghum after transplanting. Plant heights and diameters of transplants at T15 were longer than the other transplants. Conclusively, The advantages of this practice were better control of crop density and greater yields; either to fill gaps after emerging and thinning of crops or to compensate for a growth period that was too short for a complete crop cycle.

• Korean Journal of Environmental Agriculture
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• v.17 no.1
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• pp.70-75
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• 1998

A model of pond system is developed for treatment and recycling of excreta from twenty-five adult dairy cattle. It is composed of wastewater treatment ponds and small fish ponds. Those are three facultative ponds in series; primary-secondary-tertiary pond and these are designed to rear carps without feeding. A pit is constructed at the bottom of primary pond for efficient sludge sedimentation and effective methane fermentation. It is contrived to block into it the penetration of oxygen dissolved in the upper layer of pond water. The excreta from the cattle housed in stalls are diluted by water used for clearing them. The washed excreta flow into the pit. The average yearly $BOD_5$ concentration of influent is 398.7mg/l. That of the effluent from primary, secondary and tertiary pond of the system is 49.18, 27.9, and 19.8.mg/l respectively. Approximate 88, 93, and 95 % of BOD5 are removed in each pond. The mean yearly SS concentration of influent is 360.5 mg/l That of the effluent from each pond is 53.4, 45.7, and32.7mg/l respectively. Approximate 86, 88, and 91% of SS are removed in each pond. The $BOD_5$ concentration of secondary and tertiary pond can satisfy 30mg/l secondary treatment standard. The SS concentration of effluent from tertiary pond, however, is slightly greater than the standard, which results from activities of carps growing in the pond. The average yearly total nitrogen concentration of influent is 206.8mg/l and that of the effluent from each pond is 48.6, 30.8, and 21.0mg/l respectively. Approximate 74, 88, and 90% of total nitrogen are removed in each pond. The mean yearly total phosphorous concentration of influent is 20.7mg/l and that of the effluent from each pond is 5.3, 3.2, and 2.1mg/l respectively. Approximate 97, 98, and 99% of total phosphorous are removed in each pond. The high removal of nitrogen and phosphorous results from active growth of algae in the upper layer of pond water. Important pond design parameters for southern part of Korea -- areal loading of BOD5, liquid depth, hydraulic detention time, free board, and pond arrangement -- are taken up.

• Journal of The Korean Society of Grassland and Forage Science
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• v.25 no.4
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• pp.251-258
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• 2005

This study was conducted to examine the effect of application of pig manure slurry(PMS) for rye cultivation in Paddy-land on rice productivity The field experiments were carried out from 1999 to 2002 on well-grown rice in Paddy-land at Kimje, Chunbuk province in Korea. PMS was manufactured by the fermentation for 6 months in natural condition. Amount of PMS was adjusted equal to total nitrogen value relative to its value of commercial chemical fertilizers. The amount of PMS were spread evenly over the soil surface two times; first in the autumn (before sowing, end of November) and second in the spring(regrowth of rye, middle of March). The field plots were consisted of four kinds (PMS $100\%$ treatment, PMS $200\%$ treatment PMS $100\%$ treatment with half of CF (CF $50\%$), Full of CF treatment (CF $100\%$). The experiment was designed as a randomized complete block. Each treatment was replicated three times. Rices are customarily gown under tropical korean condition as annuals. The results obtained from this study were summarized as fellows. Panicle length of rice was shorter in PMS $100\%$ than other treatments. Ripening grain ratio was the lower in CF treatment. In treatment of PMS $100\%$ and PMS $200\%$, 1000 grain weight was a downward trend as compared to that of full of CF treatments, whereas number of grains per $m^2$ was increased as compared to other treatments. Number of panicles reveals that there is an increase in order; CF $50\% + PMS\;100\%>\;PMS\;100\%\;>\;CF\;100\%\;>\;PMS\;200\%$. Yield of milled rice showed hi인 in CF $100\%$ and $CF 50\%+ PMS 100\%$, but were was no significant difference among treatments. There were did not a regular tendency in the ratio of leaf sheath bright, however the ratio of lodging area was higher in $CF50\%+PMS\;100\%$ treatment than other treatments. Based on the results of this experiment, $CF 50\%+PMS\;100\%$ may be the most effective in rice productivity under application of PMS for rye cultivation in Paddy-land.

• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.3
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• pp.213-220
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• 2002

The growth characteristics, forage yields and nutritive values of heading and headless types of sorghum $\times$ sudangrass(Sorghum bicolar L.) hybrids were examined to evaluate the adaptability of new cultivars at Suwon and Chunahn for two years from 2000 to 2001 in a randomized complete block design with three replications. Eleven cultivars of heading type and 4 cultivars of headless type were used in this study. The dry matter(DM) yield of AG 2501 was highest in the heading type cultivars, and PAC F8350 in the headless type cultivars, respectively. The DM yields of heading types were slightly higher than those of headless types but there were not significantly different. Early growth and regrowth characteristics of heading type was highest in AG 2501 and GW 9110G, respectively. GW 9110G and DMD were early heading types, and AG 2501 and GW 9161F were middle heading types. AG 2501 was longest and GW 9161F was shortest in plant height. Cultivars with long leaf length were appeared to be larger fur leaf width and stem diameter. Brix content was highest in DMD as 9.7%, and disease and insect resistances were not significantly different among the heading types. Early growth of headless type cultivar, PAC F8350 was slightly lower than that of Jumbo but stronger in regrowth, wider in leaf width and stem diameter, and stronger in lodging. Comparisons of growth characters between heading and headless types of cultivars were not easy in general but between them, brix contents of heading types ranging from 6.7 to 7.9% were greatly higher than those of headless types ranging from 3.6 to 3.9%. Nutritive values such as crude protein, ADF, NDF and digestibility of headless type cultivars were higher than those of heading types. In conclusion, of heading type cultivars, GW 9110G, AG 2501, DMD and GW 9161F, and of headless type cultivars, Jumbo and PAC F8350 were recommended as high yielding cultivars with good adaptability in domestic environment.

• Journal of The Korean Society of Grassland and Forage Science
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• v.8 no.3
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• pp.92-98
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• 1988

With a purpose of finding out the effects of magnesium and boron enriched organic-compound fertilizer application on the dry matter yield, yield components and changes in the botanical composition on the hilly pasture, a field experiment was arranged with five different treatments as a randomized block design and lasted from September, 1984 to the end of growing season in 1986. The results obtained are summarized as follows : 1. As a early plant growth and development, winter hardiness, growth vigour and coverage of grasses at the plots with organic-compound fertilizer application were better comparing to single dressing. 2. Average dry matter yields for two years were shown significantly high due to increasing amount of fertilizer. This trend was same both single and organic-compound fertilizer. And dry matter yields with organic-compound fertilizer application of low (8, 693.1 kg/ha) and conventional level (12, 758.7 kg/ha) were appeared to increase by 10 and 15% than those of single dressing of Low (7, 930.6 kg/ha) and conventional level (11, 122.6 kg/ha), respectively. But it was not significant difference. 3. Dry matter yield of grasses was significantly gained by increasing amount of fertilizer. The yield of legumes at the plot without fertilization was significant higher comparing to fertilizing plots, but it was not different between low and conventional dressing levels. However, at the plots with organic-compound fertilizer application the yields of grasses were a little more increased by 8-14%, and legumes were much more gained by 26-29% than those of the same species groups with single dressing, but it was not significant between the different kinds of fertilizer in the same fertilizing level. 4. At the grassland management, the rate of legumes tended to dominate at the plot without fertilization gradually. On the other hand, the botanical compositions and the rates of grasses were much better maintained at the plots with fertilization. But the rates of legumes with organic-compound fertilizer application tended to increase a little more than those of single dressing gradually.

• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.1
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• pp.7-12
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• 2009

This experiment was conducted to compare the agronomic characteristics and productivity in introduced forage pea cultivars at the experimental field. The experiment was arranged in a randomized block design with three replications. The forage pea used in this study were two cultivars ('Livioletta', 'Austrian Pea') and one Chinese milk vetch cultivar (Chinese domestic cultivar). Flowing of 'Livioletta' cultivar was May 16th and 'Austrian Pea' cultivar was 18th May, 20 days later than the former. The 'Livioletta' cultlvar showed stronger than winter hardiness of 'Austrian Pea' cultivar. Dry matter (DM) content of 'Liviotetta' and 'Austrian Pea' cultivars were 22.5% and 20.9% chinese milk vetch showed the lowest content with 17.7%. 'Austrian pea' cultivar showed the highest DM yield with 5,617 kg/ha but the DM yield of 'Livioletta' cultivar was low with 3,652 kg/ha. The yield of CP (crude protein) and TDN (total digestible nutrient) set high at 'Austrian Pea' cultivar. And 'Livioletta' and 'Austrian Pea' cultivars showed CP content with 15.5% and 14.4% but Chinese milk vetch with 19.3%. The acid detergent fiber (ADF) and neutral detergent fiber (NDF) content of 'Austrian Pea' cultivar were 23.2% and 40.3%. Therefore 'Austrian pea' cultivar seems to be suitable varieties in paddy field as winter forage crops.

• Journal of The Korean Society of Grassland and Forage Science
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• v.37 no.2
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• pp.161-167
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• 2017

This experiment was conducted to comparison study on the productivity for certified varieties of import adaptability of silage corn in Pyeongchang area. Total eight varieties (Gangpyeongok, 31N27, 32P75, 32W86, P3156, P3394, DK 689 및 DK 729) were evaluated. The experimental design was 8 treatment of randomized block with three replications. Corn varieties were cultivated in experimental field of Pyeongchang campus, SNU from 1 May to 2 September, 2015 and plot size was $15m^2$. Plant height of 32W86 and ear height of Gwanpyeongok was the highest (p<0.05). Tasseling and silking date was 27 July-3 August and silking occurred after 1-3 day of tasseling. Average day to silking was 92 days and that of 31N27 variety was short (p<0.05). The varieties of DeKalbo Company (DK 689 and DK 729) required more times to silking. Average GDD (growth degree day) of eight varieties was $1,023^{\circ}C$ and P3352 was the lowest GDD. In the trials of resistance evaluation, P3394 was strong in disease, P3156 was the highest in insect. All varieties did not show the lodging and variety of DK 729 showed the highest stay green score (p<0.05). Average dry matter content was 30.77%, it showed higher trend in DM. 32W86 was the highest DM content among the varieties, but there was no significant difference among varieties (p>0.05). The weight per ear was the highest in 32W86 and the lowest in Gwanpyeongok. The ration of ear to whole plant was higher in 32W86 and P3394, but it was not found the significant difference (p>0.05). Average yield of fresh and DM was 59,017 and 13,476 kg/ha, respectively. DK 689 showed higher DM and TDN yield than others, but there was not significant difference (p>0.05). According to results, the difference of productivity was not found among certified variety of import adaptability of silage corn. The varieties Gwanpyeongok, 32W86 and 32P75 would be recommendable in Pyeongchang area for stable cultivation.

• Journal of The Korean Society of Grassland and Forage Science
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• v.37 no.4
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• pp.277-282
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• 2017

This study was conducted to evaluate on agronomic characteristics, forage quality and dry matter (DM) yields of mugwort (Artemisia princeps Pamp.) collected different region at Seongju in Kyeongbuk from 2014 to 2015. The experiment was arranged in randomized complete block design with three replications. Mugwort was planted on $17^{th}$ March, 2014 and harvested on $13^{th}$ September, 2014 and on $25^{th}$ May and $9^{th}$ September, 2015. DM yields of Dalsung(1), Seongju B.(1), Dalsung(2) and Sajuarissuk were 17.3, 16.8, 16.7 and $16.7(MT\;ha^{-1})$, respectively and the DM yields of those were higher (p<0.05) than the other mugworts in 2014. In 2015, DM yields of Dalsung(1), Dalsung(2), Seongju B.(1), and Sajuarissuk were 19.5, 19.3, 18.4 and $18.4(MT\;ha^{-1})$, respectively and DM yields of those were higher (p<0.05) than the others. DDM(digestable dry matter) content of mugworts was a range of 56.4 to 60.8% and that of Sajabalssuk, 60.8% was the highest. Seongju B.(1) 58.8% was higher than Seongju B.(2) 56.4% but there were no difference among the Dalsung(1) 58.4%, Dalsung(2) 58.1%, Sajuarissuk 57.7% and Yeongcheon. The result of this study indicated that Dalsung(1), Dalsung(2), Sajuarissuk and Seongju B.(1) would be recommendable for forage production.

• Restorative Dentistry and Endodontics
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• v.28 no.1
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• pp.89-99
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• 2003

The purpose of this study was to investigate the bonding of resin- based root canal sealer, AH26 when the sealer was applied as a thin layer between dentine and gutta-percha surface. In this study forty non-caries extracted human molars and resin-based root canal sealer(AH 26, DeTrey/Dentsply, Germany) were used. Disks of gutta-percha, 6mm in diameter.6mm thick (Diadent/Dentsply, Korea) for thermoplastic obturation were used and dentin surfaces were treated with 2% NaOCl(Group 1) or 2%NaOCl+17% EDTA(Group 3). Disks of gutta-Percha, 6mm in diameter.6mm thick (Diadent/Dentsply, Korea) for conventional obturation were used and dentin surface were treated with 2% NaOCl(Group 2) or 2%NaOCl+17% EDTA(Group 4). Enamel was removed by a horizontal section 1mm below the deepest portion of the central occlusal groove by using a watercooled low speed diamond saw. A second horizontal section was done around cementoenamel junction. Exposed dentin surface was cut to approximately $8{\times}8{\;}mm$ rectangular shape and was ground against 320, 400, 600 grade silicon carbide abrasive paper serially. After grinding, the dentine surface were soaked in a solution of 2% NaOCl for 30 minutes and twenty of specimens were treated with 17% EDTA solution for 1 minute. The treated specimens were washed and dried, Root canal sealer, AH26 was prepared according to the manufacture's instructions The Gutta-percha and dentin surface were coated with a thin layer of the freshly mixed seal or. The specimens were left overnight at room temperature. After their initial set, they were transferred to an incubator at $37$^{\circ}C$ for 72 h. After 72 hours, resin blocks were made. The resin block was serially sectioned vertically into stick of $1{\cdot}1mm$. Twenty sticks were prepared from each group. After that, tensile bond strength f3r each stick was measured with Microtensile Tester Failure patterns of the specimens at the interface between gutta-percha and dentin were observed under the SEM(x1000) and Stereomicroscope (LEICA M42O, Meyer Inst., TX U.S.A) at 1.25 x25 magnification. The results were statistically analysed by using a One-way ANOVA and Tukey's test. The results were as follows; 1. Tensile bond strengths($mean{\pm}SD$) were expressed with ascending order as follows: Group 1, $3.09{\pm}$ 1.05Mpa : Group 2, $6.23{\pm}1.16MPa$ : Group 3, $7.12{\pm}1.07MPa$ : Group 4, $10.32{\pm}2.06MPa$. 2. Tensile bond strengths of the group 2 and 4 used disks of gutta-percha for conventional obturation were significantly higher than that of the group 1 and 3 used fir thermoplastic obturation. (p < 0.05). 3. Tensile bond strengths of the group 3 and 4 treated with 2% NaOC1+17% EDTA were significantly higher than that of the group 1 and 2 treated with 2% NaOCl. (p < 0.05). 4. In analysis of failure patterns at the interface between sealer and gutta-percha, there were observed 49 (61%)cases of adhesive failure patterns and 31 (39%) cases of mixed failures patterns.

• Restorative Dentistry and Endodontics
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• v.28 no.1
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• pp.80-88
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• 2003

Object The purpose of this study were to evaluate the microtensile bond strength of resin fiber reinforced post to radicular dentin using resin cement according to various dentin surface treatment and to observe the inter face between post and root dentin under SEM Material and Method A total 16 extracted human single rooted teeth were used. A lingual access was made using a #245 carbide bur in a high-speed handpiece with copious air water spray. The post space was mechanically enlarged using H-file(up to #60) and Gates Glidden bures(#3). This was followed by refining of the canal space using the calbrating drill set provided in ER Dentinpost(GEBR, BRASSELER GmbH&Co. KG). The 16 teeth were randomly distributed into 4 group of 4 teeth. Group 1 teeth had their post space prepared using 10% phosphoric acid as root canal surface treatment agent during 20s. The canal was then rinsed with saline and dried with paper point. Group 2 teeth had their post space prepared using 3% NaOCl as root canal surface treatment agent during 30min. The canal was then rinsed with saline and dried with paper point. Group 3 teeth had their post space prepared using 17% EDTA as root canal surface treatment agent during 1min. The canal was then rinsed with saline and dried with paper point. Group 4 teeth had their post space prepared using 17% EDTA as root canal surface treatment agent during 1min. After rinsing with saline, the canal was rinced 10m1 of 3% NaOCl for 30min. After drying with paper point, the post(ER Dentinpost, GEBR, BRASSELER GmbH&Co. KG) was placed in the treated canals using resin cement. Once the canal was filled with resin cement(Super bond C&B sunmedical co. Ltd.), a lentulo was inserted to the depth of the canal to ensure proper coating of the root canal wall. After 24 hours, acrylic resin blocks($10{\cdot}10{\cdot}50mm$) were made. The resin block was serially sectioned vertically into stick of $1{\cdot}1mm$. Twenty sticks were prepared from each group. After that, tensile bond strengths for each stick was measured with Microtensile Tester. Failure pattern of the specimen at the interface between post and dentin were observed under SEM. Results 1. Tensile bond strengths(meen{\pm}SD$) ) were expressed with ascending order as follows group 4, $12.52{\pm}6.60$ ; group 1, $7.63{\pm}5.83$ ; group 2, $4.13{\pm}2.31$ ; group 3, $3.31{\pm}1.44$. 2. Tensile bond strengths of Group 4 treated with 17% EDTA +3%NaOCl were significant higher than those of group 1, 2 and 3 (p<0.05). 3. Tensile bond strengths of Group 1 treated with 10% phosphoric acid were significant higher than those of group 2 (p<0.05). Tensile bond strengths of Group 4 treated with 17% EDTA +3% NaOCl was significant higher than those of other groups.