• Plant Resources
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• v.7 no.3
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• pp.206-210
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• 2004

In order to find out the optimum harvest (dipping) date combined with sowing date on yield and nutrient quality of forage rye which is suitable at the Southern part of Korea, Paldanghomil variety was grown Sep. 2001 to May 2002 at Sunchon National University, and yield and nutrient quality of plant were observed. As harvest date and sowing date were delayed, the plant length was longest, number of leaves per plant was increased in the time of May 20 clipping. Fresh yield was the heaviest in the time of May 20 clipping and Oct. l0 sowing, and the most dry matter yield was the heaviest in the time of May 20 clipping and Oct. 10 sowing. Content of crude protein was the highest and that of crude fiber such as NDF, ADF, hemicellulose, cellulose and lignin were the lowest in the late time of clipping and sowing. Further more IVDMD was high and dry matter yield and digestible dry matter yield were the highest in the time of May 20 dipping and Oct. 10 sowing. Judging from the results reported above, at optimum harvest (dipping) date combined with sowing date for yield and nutrient quality of forage rye seemed to be the time of May 20 clipping and Oct. 10 sowing.

• Plant Resources
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• v.8 no.3
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• pp.258-262
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• 2005

In autumn, to determine the optimal planting date and plant density of rapeseed in southern areas of Korea, Yudal variety for autumn sowing, the highest yielding variety was grown under three different planting dates and five different plant densities. Yield components such as plant height, ear length, number of seedling stand per $m^2$, number of branches and pod length were highest at the plots with Sep. 30 of planting date and 30/20 cm drilling of plant density. Yield of seed, oil and 1,000 grains weight were highest at the Sep.30 of planting date and 30/20 cm drilling of plant density. Judging from the results reported above, at optimum planting date and plant density of rapeseed seemed to be Sep.30 of planting date and 30/20cm plant density in autumn sowing.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.2
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• pp.197-211
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• 2015

In order to investigate optimum and marginal sowing date of foxtail millet, proso millet and sorghum in middle area (Anseong, Gyeonggi province) of korea, four levels of sowing date [(May 15(1st), June 6(2th), June 26(3th), July 13(4th)] with mulching and non-mulching were treated in this experiment. We used three crops of foxtail millet, proso millet and sorghum with four varieties of Samdachal, Samdamae, Kyeongkwan1, Hwanggeumjo in foxtail millet, Leebaekchal, Manhongchal, Hwangsilchal, Hwanggeumgijang in proso millet and Nampungchal, Hwanggeumchal, DS202, Moktaksusu in sorghum achieved from RDA. In culm length, sowing date of June 26 was the highest in all varieties of foxtail millet, proso millet and sorghum. Sowing date of May 15 showed the highest ear length in foxtail and proso millet, whereas the highest ear length was obtained from sowing date of June 26 in sorghum. In numbers of leaf, sowing date of May 15 showed the highest in all three crops of foxtail millet, proso millet and sorghum. Days from sowing to heading date were reduced in Samdamae, Kyeongkwan1 and Samdachal as sowing date was late. In Hwanggeumjo it was reduced from the sowing date from May 15 to June 26, but it was same days was taken between June 26 and July 13 sowing date. Days from sowing to heading date of four varieties in proso millet were reduced as sowing date was late. Days from sowing to heading date in sorghum were reduced as sowing date was late, whereas it was increased the $4^{th}$ sowing date of July 13. There were no significant differences in growth and yield characteristics between mulching and non-mulching in four varieties of foxtail millet, proso millet and sorghum with four varieties. The highest grain numbers per panicle, 1000 grain weight and yield per 10a were obtained from sowing date of June 26 in four varieties of foxtail millet, proso millet and sorghum. In sowing date of July 13, all varieties of foxtail millet, proso millet and sorghum were not able to be ripened because of late sowing except Hwnaggeumjo, Manhongchal and Hwanggeumgijang.

• Korean Management Science Review
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• v.13 no.2
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• pp.147-161
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• 1996

Due-date is an important factor in Flexible Manufacturing System scheduling. Even though most of researchers have focused part selection and loading problem using fixed due-date assignment rules, FMSs consist of multi-function machines which facilitate alternative processes. This research investigates interactions of three dispatching mechanisms, three NSS (Next Station Selection) rules and four due-date assignment rules using simulation. Both cost-based and time-based performance measures are considered in this research.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.250-250
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• 2017

Studies were conducted to select the optimum sowing date and planting density of sesame in the middle area of Korea. To select the optimum sowing date, sesame seeds sowed from 20 April to 7 July with 15-day intervals. To select the optimum planting density, sesame seeds investigated under four different planting distances ($30{\times}10,\;30{\times}15,\;30{\times}20$, and $30{\times}25cm$)respectively in the experimental field. As seeding date was delayed, days to emergence were shortened flowering and maturing date were delayed. Delayed sowing date resulted in decreased length, capsule setting stem length and number of capsules, and branchs per plant. Number of Capsules was high sowing date on 5 May in the range of 90~95ea/plant in sesame. Also yield of sesame seeds was most high on 5 May in the range of 142kg/10a by sowing date. Sowing date up to 5 May showed no effect on grain yield, but from 5 June to 5 July decreased 27%, 68% and 86%, respectively. For all planting distances, weight of 1,000 grain was not significantly different. However, number of branches and capsules tended to increase. Number of Capsules was high planting distance of $30{\times}20cm$ and $30{\times}25cm$ in the range of 146.7~165.7ea/plant in the Geonbaekkae. Areumkkae also showed the same tendency on planting distance of $30{\times}20cm$ and $30{\times}25cm$ in the range of 122.0~147.5ea/plant, respectively. Yield of Geonbaekkae and Areumkkae seeds was most high 116kg/10a, 117kg/10a, respectively on planting distance $30{\times}20cm$. Decreased in the planting distance of sesame has increased the incidence of disease and lodging. Based on the results, we suggest a planting distance of $30{\times}20cm$ maximal growth and yield of sesame in the middle area of Korea. Considering growth characteristics, sesame yield ability, the optimum sowing date was 5 May and optimum planting pattern was founded to be two rows planting in one ridge and planting densities was $30{\times}20cm$.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.12
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• pp.1705-1711
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• 2001

Silage corn (Zea mays L) is grown extensively in livestock operations, and many managements focus on forage yield. This experiment was conducted at Seoul National University (SNU) Experimental Livestock Farm, Suwon in 1998. We determined the effect of planting date and harvest stage on forage yield and quality responses of corn hybrids (five relative maturity groups). The five maturity groups (100 d, 106 d, 111 d, 119 d and 125 d) were planted on 15 April and 15 May, and harvested at maturity stages (1/3, 1/2 and 2/3 kernel milkline). Whole plant dry matter (DM) and ear percentages had significant differences among corn hybrids. Ear percentages of early maturing corns (100 d and 106 d) were higher than for other hybrids. Ear percentage at the early planting date was higher than that at the late planting date for all corn hybrids. The DM and total digestible nutrients (TDN) yields of the 106 d and 111 d corn hybrids were higher than other hybrids, and the DM and TDN yields at the early planting date were higher than that at the late planting date. The acid detergent fiber (ADF) and neutral detergent fiber (NDF) percentages were greater for the late maturity corn hybrids. For plants of the early planting date, the ADF and NDF percentages were lower than for those of late planting date for hybrids. From the comparison among harvest stages, ADF and NDF percentages were decreased as harvest stage progressed. The TDN, net energy for lactation (NEL), and cellulase digestible organic matter of dry matter (CDOMD) were decreased as maturity of corn hybrid delayed. The TDN, NEL, and CDOMD values at the early planting date were higher than those at the late planting date among for corn hybrids. From the comparison among harvest dates, TDN, NEL, and CDOMD values were increased as harvest stage progressed. The correlation coefficient for DM percentage of grain at harvest with DM and TDN yields were 0.68*** and 0.76***, respectively. And the correlation coefficient for ear percentage with ADF, NDF, and CDOMD were -0.81***, -0.82*** and 0.73***, respectively. Our study showed differences of silage corn in forage production and quality resulting from hybrid maturity, planting date, and harvest stage. We believe that for the best silage corn, selection of the hybrid and best management practices are very important.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.1
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• pp.44-51
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• 1995

This investigation was conducted to determine the effect of the optimum planting date and place for good seed production on growth variation, grain yields, different of variety, infection of seed by fungi, and seed germination and vigor after room storage. Early maturity Korean soybean variety, Keunolkong, and introduced vegetable soybean variety, Fukura-edamame, were planted at field of YAES. and high cool land of Sajapyong in Milyang（altitude, 850m） on May 15 （early）, June 15 （mid.）, and July 15 （late） in 1991. The emergence and vegetative period gradually increased in the early planting date. The grain yield, seed weight, pod number, healthy grain yield also increased when Keunolkong was planted on early date. The healthy seed rate, Keunolkong increased in the early planting date, whereas that of Fukura also increased in the late planting date. Infection ratio of grain to phomopsis seed decay （Phomopsis spp. ' Diaporthe phaseolorum） in Fukura steadily increased in the early planting date. Infection ratio of grain to purple seed stain （Cercospora kikuchii） generally increased in the mid and late planting date. The seed germination and seedling vigor after room storage from five to six months gradually increased in the late planting date. And seed germination of Fukura rapidly decreased in the early planting date. Therefore, the optimum planting date for good seed production in early maturity vegetable soybean was June 15 in terms of harvesting time avoid a high temprature and humidity.

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.4
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• pp.217-224
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• 2001

In order to identify the growth characterization, the yield and chemical composition of Jeju barnyard grass (Echinochloa crusgalli var. fiurnentacea(Roxb) Wight) based on seeding date in Jeju region, seeding carried out the 10-day intervals from March 27 to September 30 in 2000, respectively. Plant height was 143.2 cm, showing the highest on seeding date, April 6 among that of any other seeding date. On the other hand, those of early and late seeding gradually decrease. Plant height was 119.2 an in May 16 seeding. The results of stem diameter, number of withering leaves, number of leaves and fresh weight per plant were similar to those of the plant heights. The yield of fresh, dry matter forage, crude protein and TDN found the highest on April 6 seeding, 63.5 MT/ha, 13.9 MTha, 1.1 MT/ha, and 7.6 MT/ha, respectively. In early and late seeding, the yield was gradually decreased. In seeding May 16, the yield found .38.2 MTIha in fresh forage, 6.2 MTha in dry matter forage, 0.7 MT/ha in crude protein and 3.7 MTha in TDN, respectively. According to delaying the seeding date, March 27 to May 16, the contents of crude protein (from 7.9 to 10.8%), ether extract (from 4.6 to 6.0%), nitrogen free extract (from 45.1 to 46.5%), and TDN (from 54.2 to 60.8%) were gradually increased, respectively. On the other hand, those of crude fiber (from 28.9 to 25.6%) and crud ash (from 13.5 to 11.2%) were decreased. These results showed that April 6 was the optimum seeding date with the sole object of feed production of Jeju barnyard grass under the environmental condition like as atmospheric phenomena and soil in Jeju region. (Key words : Jeju barnyard grass, Seeding date, Forage yield, Chemical composition)

• Journal of Ecology and Environment
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• v.29 no.5
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• pp.461-467
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• 2006

The growth pattern and the seasonal changes in nutrient contents of Humulus japonicus were investigated. Stem length of H. japonicus reached the maximum from 240 to 260 Julian date and the median value was found at 255 Julian date. The maximum leaf area was observed from 235 to 248 Julian date and the median value was at 240 Julian date. The maximum growth rate of the stem length ranged from 205 to 227 Julian date. The leaf area showed the maximum growth rate from 196 to 214 Julian date. The median date in the growth rate of the stem length and leaf area was 212 and 205 Julian date, respectively. The growth rate of H. japonicus was related to rainy season and precipitation. Phosphorus and sodium contents of H. japonicus were correlated with maximum potential rate of relative growth. Although stem biomass of H. japonicus was $ 1.5{\sim}3.5$ times larger than that of leaf, N content of the leaf ($4.48{\sim}5.27%$) was about 2 times higher than that of the stem ($2.00{\sim}3.62%$). High content of N might be responsible for the high growth rate of H. japonicus in summer. This result provides valuable information for appropriate timing for the removal of H. japonicus.

• Journal of Convergence for Information Technology
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• v.11 no.2
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• pp.82-89
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• 2021

The objective of this study is to propose a new Glide Path that dynamically adjusts the risky asset inclusion ratio of the Target Date Fund by simultaneously considering the market's forecast volatility as well as the time of investor retirement, and to compare the investment performance with the traditional Target Date Fund. Forecasts of market volatility utilize historical volatility, time series model GARCH volatility, and the volatility index VKOSPI. The investment performance of the new dynamic Glide Path, which considers stock market volatility has been shown to be excellent during the analysis period from 2003 to 2020. In all three volatility prediction models, Sharpe Ratio, an investment performance indicator, is improved with higher returns and lower risks than traditional static Glide Path, which considers only retirement date. The empirical results of this study present the potential for the utilization of the suggested Glide Path in the Target Date Fund management industry as well as retirees.