• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.4
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• pp.406-412
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• 2014

The influence of rainfall during the ripening stage on pre-harvest sprouting, seed viability, and seed quality was investigated in two Korean rice cultivars, Shindongjin and Hopum. When the rainfall was artificially treated in a greenhouse, HP started to pre-harvest sprouting at three days of rainfall treatment (DRT), but Shindongjin did not show pre-harvest sprouting at 40 DAH treatment and just 0.3~0.8% at 50 DAH, which was much lower than 15.3~25.8% of Hopum in the same treatment. After harvest, the seed germination of Hopum decreased about 10~25% compared to non-treated seeds, but that of Shindongjin decreased much little rate than that of Hopum. The seed longevity tested by accelerated aging decreased with prolonged rainfall period in both cultivars, but the varietal difference was clear; Shindongjin could withstand longer accelerated aging than Hopum. Shindongjin maintained its germination (>50%) ability after 15 days of accelerated aging regardless of the rainfall treatment period and time, but Hopum dropped below 50% germination ability after only 5 days of accelerated aging. In conclusion, rainfall during the ripening stage induced not only pre-harvest sprouting, but also reduced seed quality and longevity during storage, which varied between two cultivars.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.2
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• pp.224-232
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• 2019

Objective: Apart from various climatic differences, corn harvest stage and varieties are two major factors that can influence the yield and quality of corn silage in the tropics. A study was conducted to determine the optimum harvest stage of four corn varieties for silage production in Malaysia. Methods: Corn was harvested at four growth stages; silking, milk, dough, and dent stages from four varieties; Sweet Corn hybrid 926, Suwan, breeding test line (BTL) 1 and BTL 2. Using a split plot design, the treatments were then analysed based on the plant growth performance, yield, nutritive and feeding values followed by a financial feasibility study for potential commercialization. Results: Significant differences and interactions were detected across the parameters suggesting varying responses among the varieties towards the harvest stages. Sweet Corn was best harvested early in the dough stage due to high dry matter (DM) yield, digestible nutrient, and energy content with low fibre portion. Suwan was recommended to be harvested at the dent stage when it gave the highest DM yield with optimum digestible nutrient and energy content with low acid detergent fibre. BTL 1 and BTL 2 varieties can either be harvested at dough or dent stages as the crude protein, crude fibre, DM yield, DM content, digestible nutrient and energy were not significantly different at either stage. Further financial analysis showed that only Sweet Corn production was not financially feasible while Suwan had the best financial appraisal values among the grain varieties. Conclusion: In conclusion, only the grain varieties tested had the potential for silage making according to their optimum harvest stage but Suwan is highly recommended for commercialization as it was the most profitable.

• East Asian mathematical journal
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• v.34 no.5
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• pp.683-691
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• 2018

We consider an optimal control problem for an impulsive stage-structured model involving ordinary differential equations with impulsive values of initial conditions in the next year. The main goal is to maximize a profit of the catch of Pacific cod in the South Korea through optimal harvest strategy as a control of adult cod. We established necessary conditions for the optimal harvest control using idea of Pontryagin's maximum principle. The optimal harvest strategy is to numerically solve the equation by using an iterative method with the Runge-Kutta method. Finally, we compare a monthly average of fishing mortality of Pacific cod from 2013 to 2017 with monthly fishing mortality for result obtained optimal harvest strategy.

• Journal of The Korean Society of Grassland and Forage Science
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• v.15 no.2
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• pp.112-117
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• 1995

A field experiment was canied out to determine the effects of harvest time (grazing, soiling and hay stage) on the grass growth, dry matter (DM) yield, nutritive value, and weed development in reed canarygrass (Phalaris arundinacea L.) pasture. The cultivars of reed canarygrass used in this study were Palaton, Venture, Castor, and Frontier (control). The grass was harvested 3 times at hay stage, 4 times at soiling stage, and 6 times at grazing stage in 1992. The average plant height was 31-41cm at grazing, 47-59cm at soiling, and 76-86cm at hay stage. Similar DM yield was observed in Palaton(12,567 kglha), Venture(l2,435kg), and Frontier(12,762kg), and the yields of 3 cultivars were significantly higher than that of Castor(ll,025kg) (P<0.05). Total yields affected by harvest time were lO,O6 1, 1 1,832, and 14,699 kg/ha at grazing, soiling, and hay stage, respectively(P<0.05). The content of crude protein (CP) was not significantly different among cultivars. CP contents by harvest time were 21.6% at grazing, 19.3% at soiling, and 18.8% at hay stage, regardless of cultivm(P<0.05). The contents of neutral detergent fiber (NDF) and acid detergent fiber (ADF) were similar among cultivars and harvest time. However, slightly higher NDF and ADF contents were found in Frontier. The contents of Ca, P, K, and Mg were not affected by cultivars and harvest time. The appearance of weeds was high in Castor, and low in Frontier. The weeds at grazing stage(33.3-60.0%) were remarkably higher than those at soiling and hay astage (ca 10%). In conclusion, it is suggested that 3-4 times (soiling and hay stage) of harvest was recommended for grass production, nutritive value, and weed control in reed canarygrass pasture, regradless of cultivars of Palation, Venture and Frontier, except Castor.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.1
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• pp.25-34
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• 2010

Although whole crop barley (Hordeum vulgare L.) is now widely grown as a silage crop in Korea, forage production and silage quality of that for organic farm have not been published. Therefore, this experiment was conducted to evaluate the effect of harvest stage on forage production and quality of organic barley, and effect of field wilting and crushed rice for shortening of harvest date and improvement of forage quality. The experiment was split-plot design with three replications. Main plots were heading, milking and yellow stages, and sub-plot were field wilting for I day, crushed rice 10% (CR10%) and 15% (CR15%) treatments. The dry matter (DM) contents of heading, milking and yellow stages were 12.8%, 21.9% and 29.8%, respectively. The DM yields of heading, milking and yellow stages were 10,346, 15,819 and 18,336 kg/ha, respectively, and the total digestible nutrients (TDN) of these were 6,288, 9,550 and 10,178 kg/ha, respectively. The pH of milking stage showed low 4.00 pH values. The crude protein, ether extract, crude ash, non-fiber carbohydrate (NFC) and TDN contents were decreased as harvest stage progressed, while neutral detergent fiber (NDF) and acid detergent fiber (ADF) were increased. The crude ash (CA) of milking stage showed the lowest among harvest stages. Field wilting and crushed rice treatments decreased CA, NDF and ADF contents, and increased NFC and TDN contents. In vitro dry matter digestibility (IVDMD) decreased with progressed harvest stage, while field wilting and crushed rice treatments increased that of barley silage. Lactic acid and total organic acid contents of milking stage were the highest, and butyric acid of milking stage was the lowest among harvest stage. The good effect of field wilting and crushed rice was observed in heading stage. The experiment results indicate that optimum harvest stage of barley silage for organic was milking stage. The field wilting and crushed rice additive could be recommended as effective method for shortening harvest date and increasing forage quality of organic barley silage

• 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 Agricultural Science
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• v.45 no.1
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• pp.43-49
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• 2018

The species of forage crops used in this study were Italian ryegrass (cv. Kowenery), sorghum (cv. SX17), proso millet (cv. domestic) and Japanese millet (cv. Jeju). The plant height of the summer crops was the highest at the dough stage. The dry matter yield of Italian ryegrass was 902.7 kg per 10 a. The dry matter yield of the winter crop and sorghum was 11,985 kg when harvested at the dough stage rather than at the first and second harvests. The proso and Japanese millet also had higher yields for dry matter during the dough stage rather than during heading and regeneration. The acid detergent fiber (ADF) content of Sorghum was lower than that of the first and second harvest; however, the proso and Japanese millet had a higher ADF content at the dough stage. The neutral detergent fiber (NDF) content was higher at the dough stage than at the first and second harvest, and the crude protein content was also lower at the dough stage than at the first and second harvest. The crude protein production for the dry matter yield was about 84 kg in Sorghum when harvested at the dough stage. Proso millet showed no difference for the crude protein production at the heading and dough stage while the Japanese millet had a higher crude protein production. There were no differences in the total digestible nutrients (TDN) content for the three crops according to the harvesting time. Therefore, if Sorghum and Proso and Japanese millet are to be combined with Italian ryegrass, it is better to harvest them at the dough stage.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.1
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• pp.65-74
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• 2011

This study was carried out to examine the effect of harvest stage of corn on nutritive values and quality of round baled corn silage manufactured with corn grown in paddy land of Department of Animal Resources Development, National Institute of Animal Science, RDA from 2009 to 2010. Corn "Kwangpyungok" was harvested at three different growth times (milk, yellow ripen and ripen stage) and ensiled at each harvest stages. Crude protein (CP) and TDN (total digestible nutrient) contents of round baled corn silage was decreased and in vitro dry matter digestibility (IVDMD) was not changed with delayed harvest maturity. However, contents of ADF (acid detergent fiber) and NDF(neutral detergent fiber) decreased with delayed harvest maturity. The pH at three different harvest stages ranged from 3.8 to 4.0. The content of lactic acid increased with delayed harvest maturity, but the content of acetic acid decreased. And then, flieg's score reveals that there is an increase in order, ripen stage > yellow ripen stage > milk stage. Therefore, this study suggest that round baled corn silage manufactured at yellow ripen stage can improve the silage quality.

• Journal of the Korean Society of Tobacco Science
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• v.7 no.1
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• pp.39-47
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• 1985

Normally cultured aromatic tobaccos, KA 101 and KA 103, were primed progressively in three-leaf segments, either 7 days before bud, bud, or early flower stage with 7 days interval, respectively, The cured leaves were weighed for yield, graded, analyzed for quality-related constituents including volatile aroma components. Also the cured leaves were manufactured and smoked by panelists. Yield and quality by price decreased with advancing ripeness. Reducing sugar, total nitrogen, protein nitrogen decreased with successive ripeness, but reverse in this trends with nicotine, petroleum ether extracts and volatile acids components. Among volatile neutral components, furfural, furfuryl alcohol, benzyl alcohol, penethyl alcohol and p-cresol decreased, but solanone increased with delayed harvest. Neophytadiene, oxysolanone, furfuryl aceton was highest at mid harvest, which was judged to be best by panelists. Mid harvest, first primed at bud stage when leaf color comes to pale green to yellow green, seems to be highly recommendable.

• Journal of The Korean Society of Grassland and Forage Science
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• v.32 no.4
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• pp.405-410
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• 2012

This study was carried out to investigate the effect of harvest stage of rape on nutritive values and quality of round baled rape silage in field of forage crops of Department of Animal Resources Development, National Institute of Animal Science, RDA. Rape was harvested at three different growth stages (flowering, milk and dough stage) and ensiled at each harvest stages. The content of moisture of rape increased with delayed harvest maturity. However, the content of moisture of rape was controlled by pre-wilting (24 hr. and 48 hr). The content of moisture in dough stage was similar to that of haylage. The content of crude protein in round baled rape silage increased with delayed harvest maturity, but the contents of acid detergent fiber, neutral detergent fiber and total digestible nutrient decreased. The pH in all rape silage ranged from 3.8 to 4.4 at three different harvest stages, and pH in dough stage was higher than that of flowering and milk stages (p<0.05). The content of lactic acid of all rape silage increased with delayed harvest maturity (p<0.05), but the content of acetic acid decreased (p<0.05). And then, flieg's score revealed that there was an increase in order; flowering stage (100) = milk stage (100) > ripen stage (88).