• Journal of Korean Society of Forest Science
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• v.98 no.1
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• pp.125-131
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• 2009

To facilitate the sustainable forest management, Forest Service in Korea has assigned 2.9 million hectare forests as 'intensive management forests' and encouraged local governments to develop a strategic management plan for their forests. One of problems for the sustainable forest management in Korea is the skewed distribution of forest age classes. Currently the majority of forestlands in Korea is occupied by age classes III and IV. In this study, we intended to find an optimum harvest volume, which enable one to make the intensive management forest in Youngdong-Gun evenly distributed for the age classes and allow an even harvest volume through a 50 year time horizon. To develop an optimization model, we applied the goal programming technique which is adequate for a multi-purpose management planning. The results indicated that it is necessary to harvest 1.2 million cubic meters in each decade to achieve the most stable distribution of age classes for the study site. The harvest volume target resulted from this study would be used in a management planning or an associated policy making process in the future.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.2
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• pp.142-150
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• 2020

This experiment was conducted to set ideal harvest time for itallian ryegrass (IRG) seed in reclaimed land. For IRG 'Kowinearly' variety sown in both autumn and spring, the peak growth in reclaimed land occurred in 20-30 days after heading. Plant height of IRG seedings in the spring was 90.4% of the fall-sown's plants. The yield of IRG seeds in reclaimed land was generally lower than that of farm land due to poor growth conditions. After heading, the lodging and shattering increased gradually with time. The highest yield of seed in the fall-sown trial treatment was 238 kg/10a. However, in the spring-sown treatment, the highest yield reached 169 kg/10a, which was 71% that of the fall-sown treatment. To set optimum harvesting time for IRG seed, morphological changes in the plant, moisture content of seed, and germination rate were analyzed according to time series after heading. After heading, IRG stem color had turned pink in 18 days and seed color also changed after 20 days. Following 20-25 days after heading, the seed moisture content decreased to below 55% and germination rate increased to over 90%. Therefore optimum harvesting time for IRG 'Kowinearly' variety in reclaimed land was 20-30 days after heading because germination rate and yields were high and shattering percentage was low.

• The Korean Journal of Food And Nutrition
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• v.31 no.3
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• pp.408-415
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• 2018

This study aimed to investigate the changes in the ${\gamma}$-aminobutyric acid (GABA) content of bitter melon (Momordica charantia L.) cultivated from different regions, with different harvest times and at various maturation stages. Methods for observing the changes in GABA content were validated by determining the specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), and precision and accuracy using the HPLC-FLD system. Results showed high linearity in the calibration curve with a coefficient of correlation ($R^2$) of 0.9999. The LOD and LOQ values for GABA were 0.29 and $0.87{\mu}g/mL$, respectively. The relative standard deviations for intra- and inter-day precision of GABA were less than 5%. The recovery rate of GABA was in the range of 98.77% to 100.50%. The average content of GABA was 0.93 mg/g and Cheongju showed highest GABA content of 1.88 mg/g. As the time of harvest increased from May to September, the GABA content decreased from 1.56 to 0.86 mg/g. Also, maturation of the bitter melon fruit was associated with a decreased in GABA content.

• Korean Journal of Environmental Agriculture
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• v.31 no.3
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• pp.271-276
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• 2012

BACKGROUND: It is hard to control the agricultural products exceeding MRL (maximum residue limit) before forwarding. Therefore, NAQS (National Agricultural Products Quality Management Service, South Korea) established PHRL (pre-harvest residue limit) on agricultural products during their cultivation periods. This study was performed to set the PHRLs of peach during cultivation period, and also to estimate biological half-lives for residues of clothianidin and fluquinconazole. METHODS AND RESULTS: Two groups of peach were treated under Korean GAP (Good Agricultural Practices) with application time, single and triple treatments. Sample was collected over 14days (each after 0, 2, 4, 6, 8, 10, 12, 14 days. 8times), and clothianidin and fluquinconazole were analyzed by HPLC/DAD and GC/ECD, respectively. CONCLUSION: The biological half-life of clothianidin in single treatment and triple treatment was 5.2days and 7.0days. That of fluquinconazole was also 3.9days and 4.1days, respectively. The PHRL of peach on 10days before harvest was 1.4 mg/kg in clothianidin and 1.8 mg/kg in fluquinconazole.

• Korean Journal of Environmental Agriculture
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• v.41 no.2
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• pp.125-134
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• 2022

BACKGROUND: It is a very important task to block distribution of the agricultural products contaminated with pesticides in advance to protect consumers from residual pesticides among the agricultural products. Therefore, this study was performed to determine residual characteristics of pesticides in time-dependent manner and present scientific evidences for pre-harvest residue limit (PHRL) setting. METHODS AND RESULTS: The tested pesticides, chromafenozide and pyridalyl were sprayed onto the kale twice (seven day intervals) and then the plant samples were collected at 0 (after 3 hours), 1, 2, 3, 5, 7, and 10 days after the last spraying. Residual concentration of chromafenozide in kale decreased with 74.9% (of decreased fraction, field 1) and 85.3% (field 2) and pyridalyl decreased with 81.2% (field 1) and 85.8% (field 2), calculated by comparisons of the concentrations at 0 day and 10 days. Also biological half-lives of chromafenozide in kale were 5.6 day (field 1) and 3.4 day (field 2), and those of pyridalyl were 4.3 day (field 1) and 3.5 day (field 2). CONCLUSION(S): If the residues of chromafenozide and pyridalyl in kale from 10 days before harvest are less than 37.6 mg/kg and 58.9 mg/kg, respectively, it is expected that safe kale below MRL can be supplied on the pre-harvest day.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.3
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• pp.212-218
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• 2011

This study was performed to determine the relative quality of mungbeans harvested in bulk after applying a labor-saving cultivation (LSC) method, compared to mungbeans harvested three different times under the conventional cultivation condition. There was no significant difference in starch, crude protein, and vitexin or isovitexin content of seed according to the cropping system or harvest time. The mungbeans grown under the LSC method had the highest crude fat content, followed by mungbeans from the third-, the second- and the first-harvest mungbeans under the conventional cultivation. No significant difference was found in the composite ratio of saturated fatty acids to unsaturated fatty acids according to cropping system or harvest time. The second-harvest mungbeans grown under the conventional cultivation condition had 17 different types of fatty acids, while the third-harvest mungbeans grown under the conventional cultivation and those grown under the LSC condition had the fewest types of fatty acids with 12. Of the major saturated fatty acids, palmitic acid and arachidonic acid had the highest composite ratio in the first conventional cultivation followed by the second, the third and the LSC. However, stearic acid showed the opposite tendency. Of the major unsaturated fatty acids, linoleic acid had the highest composite ratio in the first conventional cultivation, followed by the second and third conventional cultivation and the LSC. Amylogram characteristics of the mungbeans were significantly different according to cropping system and harvest times. The mungbeans harvested after the first conventional cultivation had significantly higher pasting temperature, peak viscosity, holding strength viscosity, final viscosity and breakdown, while mungbeans harvested after the third conventional cultivation had significantly higher setback viscosity. In contrast, the mungbeans harvested under the LSC methods had a significantly lower amylogram value. When harvest rate, color values and amino acid content of sprout were measured, mungbeans grown under the LSC conditions had a low harvest rate of sprout, but had Hunter's color values and amino acid content of sprout similar to those of mungbeans grown under the conventional cultivation condition.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.353-364
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• 2020

Recently in Korea, soybean harvesting has been delayed due to rainfall during the harvesting season, resulting in a reduction in yield and seed quality. This study was conducted to analyze the changes in yield and seed quality during delayed harvest with rainfall treatment using different harvesting methods, including field harvesting and polyethylene film covering after cutting fully-matured soybean plants (PE covering after cutting), with two major Korean soybean cultivars (Glycine max L), Pungsannamulkong and Daewonkong. The shattering rate of Pungsannamulkong, which is higher than that of Daewonkong, increased up to 41.8% when the harvest was delayed for 40 days without rainfall treatment by harvesting with PE covering after cutting. The weight of 100 seeds tended to decrease slightly as harvesting was delayed. When Daewonkong was harvested using the PE covering after cutting method with rainfall treatment, the yield decreased to the lowest level with a 0.8 kg ha^-1 daily reduction rate. Pungsannamulkong showed the lowest yield when harvested using PE covering after cutting without rainfall treatment with a 3.4 kg ha^-1 daily reduction rate. The infected seed rate increased according to the harvest delay in both cultivars, and significant differences were observed according to rainfall treatment and harvesting method. The germination rate was maintained above 95% even after 40 days of delayed harvest if there was no rainfall treatment. However, with rainfall treatment, the germination rate was significantly lowered as harvesting time was delayed. In the field harvesting with rainfall treatment, the germination rate decreased to 77.2% for Daewonkong and 76.5% for Pungsannamulkong after 40 days of harvest delay. For the 100-seed weight, effects of individual treatments and interactions between treatments were not observed. In contrast, the effect of interactions between treatments on the shattering rate was significant in both cultivars, indicating that the shattering rate had the greatest impact on the yield changes during delayed harvest.

• Preventive Nutrition and Food Science
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• v.21 no.2
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• pp.97-103
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• 2016

In our previous study, an early-maturing variety of rice (Oryza sativa L.), Jinbu can have feature with unique green color, various phytochemicals as well as nutritive components by the optimal early harvesting, called Green Rice$^{(R)}$ (GR). The aims of the present field experiments were to evaluate the changes in the weight of 1,000 kernels, yield, and contents of proximate and bioactive compounds in Chuchung, a mid-late maturing variety, during the pre-harvest maturation of rough rice and to research the appropriate harvest time and potent bioactivity of Chuchung GR. The weights of 1,000 kernels of Chuchung GR dramatically increased until 27 days after heading (DAH). The yields of Chuchung GR declined after 27 DAH and significantly declined to 0.0% after 45 DAH. The caloric value and total mineral contents were higher in the GR than in the full ripe stage, the brown rice (BR). In the GR, the contents of bioactive compounds, such as ${\gamma}$-aminobutyric acid, ${\gamma}$-oryzanol, and ${\alpha}$-tocopherol, were much higher (P<0.05) than those in the BR, specifically during 24~27 DAH. Therefore, bioactive Chuchung GR can be produced with a reasonable yield at 24~27 DAH and it could be useful for applications in various nutritive and functional food products.

• International Journal of Industrial Entomology and Biomaterials
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• v.40 no.2
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• pp.33-40
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• 2020

Recently mulberry has been commercialized but it loses its marketability rapidly after harvest. In this study, characteristics of mulberry were examined at different storage temperature after harvest using the typical Korean mulberry cultivars. Postharvest spoilage fungi on the various mulberry cultivars, Cheongilppong, Daeshim, and Gwasang No. 2 was observed 2, 2, and 1 d, respectively, after harvest at 28℃. However, at 4℃, the day was 8, 7, and 4 d, respectively. At 28℃ storage condition, the weight loss behavior of mulberry did not showed significantly different among them. However, at 4℃ storage condition, mulberry Cheongilppong loses its weight rapidly compared to Daeshim and Gwasang No. 2. Sugar content of mulberry stored at 4℃ was nearly constant, but stored at 28℃ decreased with storage time. The acidity of mulberry slightly decreased with storage time and then increased. Juice leakage of frozen mulberry leaked abruptly within 6 h from the fruit body and then flattened at 25℃. The results of our study, the postharvest characteristics of mulberry were affected by mulberry cultivar and need to further study to increase the shelf life.

• Food Science and Preservation
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• v.10 no.4
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• pp.447-453
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• 2003

Causal factors related to the skin disorder such as black stains during cold storage of 'Niitaka' pear fruit are of great importance to solve the postharvest disorder problems. The morphological and biochemical changes observe of pear skin affected by different harvest times and storage environments. Occurrence rate of black stain in 'Niitaka' pear fruit was the highest in newspaper bagging with 75% among various bagging materials at harvest time because of the high relative humidity within the double layer paper bags. During cold storage, the rate was 54～100% in 30 $\mu\textrm{m}$ polyethylene (PE) film packaging. As the harvest time was postponed, the rate increasedduring cold stoinge. The into was 1.5 to 2.4 times higher in pears harvested in late September than in those harvested in early and mid October. There was no significant difference in occurrence of black stain fruit between the 30 and 50 $\mu\textrm{m}$ PE film bags. The causal fungus of the black stain pear was assumed as Gloeodes pomigena (Schweintz, 1920). The treatment of 0.1～0.5 ppm ozone gas prevented the occurrence of the pear fruit black stain until 180 days after cold storage. The ozone treatment on the affected fruit was also effective in preventing the progress of the black stain.