• Journal of The Korean Society of Grassland and Forage Science
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• v.23 no.2
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• pp.107-114
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• 2003

Growth characteristics and seed productivities of orchardgrass "Hwabsung 2 Ho" cultivated for seed production were examined in the NLRI from 2000 to 2002. The experimental design was a split-plot arrangement with three replications. The main-plots were three drill widths of 15, 30 and 45cm, and subplots were four nitrogen application levels of 45, 90, 135 and 180kg/ha in early spring. Lodging was less in 45cm of drill width than in 15 and 30cm and was not severe by 90kg per ha of nitrogen including 45cm of drill width. Number of panicles per $1\m^2$ was tended to be more in 15cm of drill width than in 30 or 45cm. Among 45cm of drill widths. 45kg per ha of nitrogen had most numerous panicles. Panicle length, number of 1st branch, weight of 1,000 grain, and germination of 30 or 45cm of drill width showed better characters than that of 15cm. Seed yield was not statistical different among the treatments but was some more in 30cm of drill width, and was tended not to be different among nitrogen levels. Therefore, considering lodging tolerances, seed yield components, and mechanizations, treatment with 45cm of drill width including 45kg per ha of nitrogen in early spring was better than other treatments for orchardgrass seed production.

• Atmosphere
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• v.20 no.1
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• pp.27-35
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• 2010

This study analyzes the climate change in Korea and its impact on the occurrence of forest fire events. The forest fire occurrences in Korea tend to concentrate around large cities. In addition, the spatial distribution of the forest fire occurrence seems to agree with local climate conditions. Though the occurrence of the forest fire shows strong interannual variation, it also exhibits a positive trend. Because the forest fire frequently occurs during early spring, we examined long term climate variability in Korea for the early spring seasons. The climate change in Korea generally has brought warmer, drier, and less precipitable conditions during the early spring. The changes of the atmospheric conditions provide favorable condition for the forest fire. The climate changes in Korea also depict distinct spatial variability according to the atmospheric variables. We compared the regional trend of the fire occurrence with the climate trends. The results show the sharpest growing in the forest fire occurrence over southwest of Korea. This study suggests that the decrease in the precipitation day might affect the sharp increasement of the forest fire occurrence in the southwest of Korea.

• Journal of the Korean Wood Science and Technology
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• v.49 no.6
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• pp.550-565
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• 2021

This study's objective was to conduct species identification and tree-ring dating of wooden elements used in Mungyeong Juheulgwan of Joryeong (Gate No. 1). Of the 84 wooden elements evaluated, 76 were confirmed to be hard pines, 5 were soft pines, and 3 belonged to Abies spp. For tree-ring dating, cores of the wooden elements were collected using a drill, and ring-width plots of individual samples were constructed using the TSAP software. The results of performing tree-ring dating for the outermost ring of 59 hard pine wooden elements revealed the following 4 felling dates: summer of 1708-late fall of 1709, summer of 1792-early spring of 1794, late fall of 1838-early spring of 1840 and 1867, and early spring-fall of 1872. These felling dates were found to be consistent with those in the construction and repair records of the Annals of Joseon Dynasty, Juhulgwan Jungsugi, and those engraved on Juhulgwan Walls. It is believed that some of the wooden materials harvested at that time were stored and used since there was a difference of approximately10 years between the repair records and felling dates.

• Journal of The Korean Society of Grassland and Forage Science
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• v.5 no.2
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• pp.100-105
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• 1985

To find out the optimum level of nitrogen fertilization and better distribution of application time for seed production of Festuca arundianacea S. (var. Alta), this filed experiment was performed at Livestock Experiment Station in Suweon, during 1979 to 1981. The treatments used in this study were three nitrogen fertilizing levels (120, 180 and 240kg/ha) and four different methods of nitrogen distribution (i. single application of whole amount in early Spring, ii. 50 percent each in Autumn and early Spring, iii. 50 percent each in early Spring and at begin of heading stage and iv. 50 percent in Autumn and 25 percent in early Spring and at begin of heading stage respectively). The experiment was arranged as a split-plot design with 4 replications and performed at the experimental field of the Livestock Experiment Station in Suweon, during 1979 to 1981. The results obtained are summarized as follows: 1. Date of heading stage of Festuca arundinacea was about May 21 and that of flowering stage was June 1 to 3. The optimum stage for the seed harvesting of Festuca arundinacea (var. Alta) was June 25 about 22 to 23 days after full flowering stage. Average plant height was about 127cm and the panicle length, 24cm. 2. 1000 grain weight was 2.72g and the number of panicles were 85 to 107 per square meter. 3. The mean seed wield for two years was 678.8kg/ha with the average of whole treatments and 781.9kg/ha with the best treatment (50 percent in Autumn and 25 percent in early Spring and at begin of heading stage with 240kg/ha respectively). 4. The average germination rate of harvesting seeds was 87.0 percent and it was increasing trend according to frequent application of fertilizer. 5. The average DM yield of aftermath seed harvesting was 6155kg/ha with two cut, and it was the largest DM yield from the higher nitrogen level and also from the single application in early Spring.

• Journal of The Korean Society of Grassland and Forage Science
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• v.20 no.3
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• pp.161-168
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• 2000

The experiment was carried out to investigate the effect of extension of grazing duration in late autumn on grass growth in following spring, in order to improve the rate of self-sufficiency for roughage feed. Plant height, total biomass and litter production of herbage were increased when the grazing was finished early in late autumn. The proportions of clover and litter, and amounts of animal intake were decreased, with extended grazing duration in late autumn. But when the grazing was finished late in autumn, the contents of crude protein (CP, %) of herbage were increased, contents of acid detergent fiber (ADF, %), neutral detergent fiber (NDF, %) and crude ash (%) were decreased in pasture after grazing, therefore the contents of total digestible nutrients (TDN, %) and relative feed value (RFV) of herbage were improved. The early end grazing showed that plant height, total biomass and litter production of herbage in following spring were higher than those in late end grazing. However, increased yields were not significantly different among end grazing treatments (0.12-0.15 tonha), except for the final end grazing in late autumn (0.01 tonha). With extended grazing duration in late autumn, the contents of CP of herbage in following spring were increased, contents of ADF, were decreased, and RFV were improved. (Key words : Extension of grazing duration, Plant height, Biomass, Amount of intake, Increased yield, Crude protein, TDN) rll\ulcorner c# qiil x i 9 ~ 1 a% * (College of Natural Resources, Taegu Univ., Kyongsan, 71 2-714, Korea) * $4 4 qiil 34 qq(Co1lege of Liberal Arts & Sciences, Yonsei Univ., Wonju, 220-701, Korea) '* 8 * jL@%ft@ &@%(Faculty of Agriculture, Hokkaido Univ., Sapporo, 060 Japan)

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.4
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• pp.275-280
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• 2015

In order to figure out the future drought characteristics of the Jeonju plains, the major crop production area in Korea, daily agricultural drought indexes based on soil water balance were calculated for the relevant 12.5 km by 12.5 km grid cell using the weather data generated by the RCP8.5 climate scenario during 1951-2100. The calculations were grouped into five climatological normal years, the past (1951-1980), the present (1981-2010), and the three futures (2011-2040, 2041-2070, and 2071-2100). Results showed that the soil moisture conditions in early spring, worst for both the past and present normal years, will ameliorate gradually in the future and the crop water stress in spring season was projected to become negligible by the end of this century. Furthermore, the drought frequency in early spring was projected to diminish, resulting in rare occurrence of spring drought by that time. However, the result also showed that the soil moisture conditions during the summer season (when most crops grow in Jeonju plain) will deteriorate and the drought incidence will be more frequent than in the past or present period.

• Korean Journal of Agricultural Science
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• v.44 no.3
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• pp.400-408
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• 2017

This experiment was conducted to estimate the livestock carrying capacity per unit area of Hanwoo heifer with determine the quality of the forage by evaluating the productivity and nutritive value of spring seeding oats (Avena sative L.) according to different seeding and harvesting timings. Dry matter yields were the highest at 13.62 tons per ha when oat was seeded on March 15 and harvested on June 8 (p < 0.05), while the lowest yield of 6.29 tons per ha was obtained when seeded on February 25 and harvested on May 19 (p < 0.05). The highest crude protein yield of 1.27 tons per ha (p < 0.05) was obtained when seeded on March 5 and harvested on June 8. The total digestible nutrient yield was the highest at 7.38 tons per ha when harvested on June 8, the last harvest of the experiment (p < 0.05). In the northern part of Gyeongbuk province, spring seeding oats at the beginning of March, rather than in the middle of March, showed good annual livestock carrying capacity per unit area. According to harvest timing, the plot harvested on June 8 showed the highest livestock carrying capacity with an average of 6.53 heads (p < 0.05). In conclusion, in the northern part of Gyeongbuk province in spring, it is better to seed oat early in March and to harvest early in June to increase the livestock breeding capacity, considering dry matter productivity and feed value.

• Journal of Plant Biology
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• v.17 no.2
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• pp.53-62
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• 1974

A study was made on the primary production of Lake Changjamot during the spring season of 1973 by menas of the oxygen method. The stratification of temperature and dissolved oxygen were formed in May with the stratified structure of phytoplankton. The range of Secchi disc transparency was from 0.8m to 2.3m during the nine months of this investigation, which was begun in January, 1973. The value was lowest in early June when the phytoplankton blooming reached the peak. The concentration of PO4-P, NH3-N, NO3-N and NO3-N was reduced at the beginning of the phytoplankton blooming and increased again after May except PO4-P. It might have been caused by the inflow of the nitogenous fertilizer from the surrounding agricultural area since May when farming was started. The total amount of chlorophyll-a in the entire water column varied from 25mg/$m^2$ to 277mg/$m^2$ from January till September with the maximum value occurring in early June. These values show a considerable eutrophication of the in comparison with the data obtained in 1969. The daily gross production in the lake varied from a low of 655mgC/$m^2$ to a high of 2,859 mgC/$m^2$ during the spring season and this corresponds to the variation of the amount of chlorophyll. The total amount of daily respiration varied from 650mg C/$m^2$ in winter to 2,307 mg C/$m^2$ in late spring and exceeds gross primary production especially in late May showing the negative balance of daily production and consumption of organic material at that time. In conclusion, Lake Changjamot is a fairly productive and a moderately autotrophic lake and has been eutrophicated much during the past four years.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.2
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• pp.97-102
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• 2010

This experiment was carried out to know the possibility for cultivation of Italian ryegrass (Lolium multiflorum Lam.) by spring seeding in Grassland and Forages Division, National Institute of Animal Science, RDA, Cheonan from 2007 to 2008. In spring seeding cultivation, heading date of early maturity variety, 'Kospeed', was on 14 May, but late maturity variety, 'Hwasan 101', was not heading up to harvesting date. Dry matter yield of 'Kospeed' (6,819 kg/ha) was higher than that of 'Hwasan 101' (4,409 kg/ha) by 55%. Crude protein (CP) and total digestible nutrients(TDN) of 'Kospeed' were 15.6% and 62.1%, respectively and that of 'Hwasan 101' were 20.3%, and 67.5%. In these result, when cultivation of Italian ryegrass by spring seeding, selection of early maturity variety have a decided advantage for high productivity.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.345-345
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• 2017

In order to reduce rice cultivation area in paddy fields and to increase domestic self-sufficiency of imported upland grain, it is necessary to increase double cropping area of upland crops in paddy field in accordance with decrease of rice consumption in Korea. The double cropping of spring potato-summer grain maize can be combined because of enough growing season in the southern plain of Korea. Spring potato, which is profitable, can be planted in the late February and harvested in the late May as the main crop. Subsequent grain maize can be planted in early June and harvested in November (maturity in the early October). Spring potato (variety Soomi) yielded $2,544kg\;10a^{-1}$ (tuber) when planted in late February, 2016. When maize was planted in June as the second cropping crop, though growth of plant decreased much, grain yield decreased slightly compared to normal planting in April or May. There was enough time to dry maize ear in the field after maturity before harvesting, which saved labor and time for grain drying, since there is no autumn planting at the double cropping of spring potato-summer grain maize. When grain maize (variety Gwangpyeongok) was planted in the early June (June $10^{th}$), average grain yield of above $860kg\;10a^{-1}$ over 2 years of 2015 and 2016 was obtained, and the annual total yield (potato tuber + maize grain) of 3,400 kg $10a^{-1}$ was obtained. The result indicates that the double cropping of spring potato-summer maize using paddy fields in southern plain of Korea, could contribute to the self-sufficiency of upland crops through the maximum production.