• The Plant Pathology Journal
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• v.30 no.2
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• pp.125-135
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• 2014

A population model of bacterial spot caused by Xanthomonas campestris pv. vesicatoria on hot pepper was developed to predict the primary disease infection date. The model estimated the pathogen population on the surface and within the leaf of the host based on the wetness period and temperature. For successful infection, at least 5,000 cells/ml of the bacterial population were required. Also, wind and rain were necessary according to regression analyses of the monitored data. Bacterial spot on the model is initiated when the pathogen population exceeds $10^{15}cells/g$ within the leaf. The developed model was validated using 94 assessed samples from 2000 to 2007 obtained from monitored fields. Based on the validation study, the predicted initial infection dates varied based on the year rather than the location. Differences in initial infection dates between the model predictions and the monitored data in the field were minimal. For example, predicted infection dates for 7 locations were within the same month as the actual infection dates, 11 locations were within 1 month of the actual infection, and only 3 locations were more than 2 months apart from the actual infection. The predicted infection dates were mapped from 2009 to 2012; 2011 was the most severe year. Although the model was not sensitive enough to predict disease severity of less than 0.1% in the field, our model predicted bacterial spot severity of 1% or more. Therefore, this model can be applied in the field to determine when bacterial spot control is required.

• Horticultural Science & Technology
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• v.28 no.6
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• pp.959-963
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• 2010

This study was conducted to investigate the effect of planting dates using garlic bulbils for production of seed garlic. The planting dates were examined using 0.2 g bulbils of 'Namdo' or 'Danyang'. For the planting dates study conducted in the middle regions, the bulbils of 'Danyang' planted in autumn produced bulb weight ranging from 3.1 to 3.5 g and percentage of harvest ranged from 61 to 71. The bulbils of 'Danyang' planted in spring produced bulb weight ranging from 1.8 to 2.8 g and percentage of harvest ranged from 53 to 60. The most desirable planting date was in the early October for the middle regions. For the planting dates study conducted in the southern regions, the bulbils of 'Namdo' planted in autumn produced bulb weight ranging from 1.8 to 3.0 g and percentage of harvest ranged from 74 to 89. The bulbils of 'Danyang' planted in spring produced bulb weight ranging from 0.6 to 1.0 g and percentage of harvest ranged from 47 to 56. The most desirable planting date was in the mid and late September for the southern regions.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.2
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• pp.125-131
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• 1994

This experiment was canied out to study -the effects of different seeding date on the yields and nutritional value of Pearl millet. Seeding dates were $S_1$,$S_2$,$S_3$,$S_4$, and $S_5$, and harvest dates were $S_1$, (7 July) and $S_2$, (18Augst), respectively. The results were summarized as follows: 1. Plant length was not influenced by seeding date at each harvest. The seeding date at $S_4$,showed the longest plant length of 90.4 an on average per year, which was longer by 17 cm compared to 73.3 cm harvested at $S_5$. 2. Total dry matter yield was not significantly different among seeding dates. Total dry matter yield in 1993 increased according to delayed seeding date from $S_1$ to $S_4$. Dry matter yield of 17.3 tonha was obtained in $S_4$. 3. The relative yield of leaf tended to increase with delayed seeding date, and varied from 60% to 69%. 4. Dry matter ratio decreased with delayed seeding date from $S_1$,(20 April) to $S_5$ (30 May), and varied from 15.6% to 12.3%. 5. Crude protein content of leaf at 1st and 2nd harvest and stem at 1st harvest were significantly different among various seeding dates. Avenge crude protein content increased with delayed seeding date from 9.0% at $S_1$ (20April) to 12.8% at (30 May) $S_5$ (30 May). 6. NDF and ADF of leaf at the 1st harvested were significantly different among seeding dates. NDF content decreased with delayed seeding date from 61.9% to 57.8%, and ADF content decreased with delayed seeding date from 34.8% to 32.2%.

• Journal of The Korean Society of Grassland and Forage Science
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• v.13 no.3
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• pp.195-202
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• 1993

This experiment was carried out to investigate the eft'ects of different seeding dates on the agronomic characteristics, forage yield and quality of fall sown cats(Avena sativa L.). The experiment was conducted at the forage experimental field, Seoul National University. Suweon in 1990. The results obtained are summarized as follows; 1. Present data indicated that plant and ear heights were decreased as the seeding date was delayed. Dry matter accumulation was increased due to the higher plant and ear heights. 1. When oats was seeded on August 20. the first heading and 50% heading dates were recorded on October 4 and 15, respectively. And when oats was seeded on August 25. the first heading and 5 0'!4 heading dates were observed on October 13 and 18. respectively. As seeding date was delayed for one day. the heading date was delayed for two days. 3. The dry mattcr percentage of oats seeded on August 20 was 20.1%, but that of oats seeded after August 10 was 15.1 to 16.7%. 4. According to the contents of CP. ADF and NDF, oats seeded on August 20 and 25 was evaluated to be the 3rd or 4th grade hay. and the other oats sceded after August 15 was recorded the 2nd or 3rd grade hay as proposed by AFGC. 5. There are no significant dry matter yield differences among the seeding dates of oats such as August 20, 25 and 30. but a significant yield difference was recorded between oats seeded in August and September. The same trend as the dry matter yield was observed in in vitro digestible dry matter and crude protein yields of oats seeded in August and September. According to the results. early seeding of early matuaring oats may be a better option than late seeding after August 30 for silage or hay production following silage corn harvest in the middle northern area of Korea.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.4
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• pp.316-323
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• 1994

In order to reduce the problems from the presence of rye crop residues in maize establishment and yield, and also to improve the growth, productivity and nutritive value of rye(Seca1e cereal L.). an experiment was canied out to determine the variety effect of rye on the forage production system and the eft'ect of seeding and harvesting dates on the production and quality of rye. 'This experiment was conducted at the forage testing field of S.N.U., Suweon, from September 1986 to May 1989. Heading date of an early maturing rye variety, Wintermore. was earlier 10 days than that of a late maturing rye variety, Kodiak. A 15-days delay in the seeding dates of early and late maturing varieties of rye tended to delay the heading dates of the rye varieties for 3 and 4 days, respectively. Dry matter and in vitro digestible dry matter yields were markedly increased with earlier seeding date. Before 20 April, the DM and IVDDM yeilds of an early maturing rye variety, Winterrnore. were higher than those of a late maturing rye variety, Kodiak. However, no such a trend was found between the early and late maturing varieties of rye after 27 April. Less than 35% of ADF was recorded until the harvesting dates of 13 and 27 p r i l for early and late maturing rye varieties, respectively, but less than 46% of NDF was maintained until the harvesting drtte of 13 April for botg varieties. Based on the results obtained from this experiment. it may be concluded that the most desirable forage production from corn-rye double cropping system is to advance the seeding time of rye toward the first 10 days of September as well as harvesting time toward the first heading stage with an early maturing rye variety.

• Atmosphere
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• v.32 no.4
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• pp.367-379
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• 2022

In this paper, the evaluation of the performance of Korea Meteorological Administratio (KMA) Global Seasonal forecasting system version 6 (GloSea6) is presented by assessing the effects of larger ensemble size and carrying out the test using different initial conditions for hindcast in sub-seasonal to seasonal scales. The number of ensemble members increases from 3 to 7. The Ratio of Predictable Components (RPC) approaches the appropriate signal magnitude with increase of ensemble size. The improvement of annual variability is shown for all basic variables mainly in mid-high latitude. Over the East Asia region, there are enhancements especially in 500 hPa geopotential height and 850 hPa wind fields. It reveals possibility to improve the performance of East Asian monsoon. Also, the reliability tends to become better as the ensemble size increases in summer than winter. To assess the effects of using different initial conditions, the area-mean values of normalized bias and correlation coefficients are compared for each basic variable for hindcast according to the four initial dates. The results have better performance when the initial date closest to the forecasting time is used in summer. On the seasonal scale, it is better to use four initial dates, where the maximum size of the ensemble increases to 672, mainly in winter. As the use of larger ensemble size, therefore, it is most efficient to use two initial dates for 60-days prediction and four initial dates for 6-months prediction, similar to the current Time-Lagged ensemble method.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.3
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• pp.169-175
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• 2022

This study aimed to examine the changes in dry matter yield and growth characteristics of alfalfa (Medicago sativa L.) in response to variations in sowing dates during the autumn season of 2021-22 in a dry paddy field of Chilbo-myeon, Jeongeup-si, Jeollabuk-do. Treatments comprised four sowing dates at 10-day intervals, i.e., October 8, October 18, October 28, and November 8, 2021. The winter survival rate of alfalfa showed a significant difference between different treatments but was at a satisfactory level for all (p<0.05). The winter survival rate for the fourth sowing date, a month later than the first sowing date, was approximately 11.7% lower than that for the first sowing date. The plant height ranged between 82.3-93.1 cm and 60.5-63.7 cm at the first and second harvest, respectively, smaller at the second harvest than at the first harvest. The total dry matter yield of alfalfa was the highest at 13,316 kg/ha for the first sowing date, and the later the sowing date, the lower the dry matter yield. The protein content of alfalfa ranged between 13.6-17.3% in the first harvest, lower than the standard alfalfa protein content of 20% or more. In relative feed value, the first sowing (Oct. 8) was the most significantly higher in the first harvest (p<0.05). These results suggest that the early and mid-October sowing dates are optimum for sowing alfalfa during autumn and result in improved plant growth, dry matter yield, protein content, and winter survival compared to those at later sowing dates. Therefore, dry paddy fields can be safely employed for alfalfa cultivation with sowing dates in early and mid-October during autumn.

• Journal of The Korean Society of Grassland and Forage Science
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• v.43 no.3
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• pp.156-161
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• 2023

This study was conducted to determine the appropriate seeding dates by verifying the difference in winter survival and productivity of alfalfa according to fall sowing dates in the central area of South Korea. The experiment was conducted for 2 years (2020 and 2021) at the field in the Department of Animal Resources Development, NIAS located in Cheonan. Sowing dates started from September 18 to November 8 with 10 days of intervals during 2020 and 2021; SO1 (September 18), SO2 (September 28), SO3 (October 8), SO4 (October 18), SO5 (October 28), and SO6 (November 8). After sowing, the winter survival rate was measured in the spring of the following year, and the dry matter yield was measured by harvesting at 10% flowering and harvesting five times a year. SO6 failed to winter survival, and SO5 also had a lower winter survival rate than SO1~4 (p<0.05). The average annual dry matter yield of alfalfa linearly decreased with delaying sowing dates (p<0.05). The feed value did not differ in the same year by delaying the sowing date in the same year. These results suggest that sowing date should be started before October 18 to increase winter survival and productivity of alfalfa in the central area of South Korea.

• Journal of Ecology and Environment
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• v.36 no.1
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• pp.65-71
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• 2013

The concentration of airborne pollen is related to meteorological parameters. The main purpose of this study was to determine the correlation between airborne pollen and meteorological parameters in Ulsan based on sampling from 2010 to 2011. The primary factors of interest were differences in the pollen scattering start date, end date, and peak date, and the fluctuations in pollen concentration. The meteorological parameters that affected the start and peak dates of the pollen season were as follows. For Pinus and Alnus, the dates were correlated with sunshine and an increase in temperature, whereas for Quercus, the dates were correlated with increasing temperature. During the pollen season, Alnus peaked when the temperature was highest and Pinus peaked when the relative humidity was lowest. The concentration of airborne pollen was correlated with meteorological parameters during the sampling period as follows: Pinus, Alnus, and Humulus pollen concentrations were positively correlated with increasing temperature and negatively correlated with rainfall and relative humidity; Humulus pollen concentration was positively correlated with sunshine; and Quercus and Humulus pollen concentrations were positively correlated with wind speed.

• Industrial Engineering and Management Systems
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• v.10 no.1
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• pp.1-6
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• 2011

This paper describes the issue of batch scheduling.In food production, the lead-time from produc-tion to sale should be decreased becausefreshness of the product is important. Products are shipped at diverse times depending on a demand of sellers, because the types of sellers has become diversified such as super-markets, convenience stores and etc. production of quantity demanded must be completed by time to ship it then. The authors consider a problem with due-dates constraints and construct the algorithm to find the opti-mal schedule that satisfy the due-dates constraint, batch size constraint, inventory time constraint and mini-mize total flow time.