• Journal of The Korean Society of Grassland and Forage Science
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• v.38 no.4
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• pp.202-209
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• 2018

This study was conducted to compare annual productivity of whole crop rice and winter crops in paddy field of southern region in Korean peninsular. Whole crop rice (WCR) varieties used in this experiment were Suwon 605, Yeongwoo, and Mogwoo bred at the National Institute of Crop Science (NICS), and Rye (Gogwoo), Italian ryegrass(IRG, Greenfarm) and Triticale (Choseong) were used as winter crops. Each crop was cultivated using the standard cultivation method and harvesting of whole rice was carried out about 30 days after heading date. The dry matter (DM) content was the lowest in Italian ryegrass (p<0.05), and the highest value was 29.4% in triticale. The dry matter yield of rye was the highest (p<0.05), and there was no significant difference between Italian ryegrass and triticale (p>0.05). There was no difference in forage quality among seeding time of each species, but there was a difference among the species (p<0.05). In particular, rye showed lower CP, IVDMD, TDN and RFV values than other species. The average dry matter production of whole crop rice was 18,484 kg/ha, but there was no significant difference among the cultivars (p>0.05). Crude protein (CP) content was significantly lower in Mogwoo than other and TDN and RFV values were the highest in Mogwoo. In the annual productivity evaluation, combination of rye-Suwon 605 showed the highest DM yield at 26,515kg/ha. Based on the above results, it was concluded that the combination of Suwon 605-rye (Gogwoo) was the most effective cropping system for annual forage production using whole crop rice and winter crop in the southern region of Korean peninsular.

• Journal of Food Hygiene and Safety
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• v.33 no.6
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• pp.447-452
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• 2018

Water is an important component in the production of fresh produce. It is mainly used for irrigation and application of pesticides and fertilizers. Several outbreaks cases related to fresh produce have been reported and water has been identified as the most likely source. On the other hand, wildlife has been identified as a possible source of the waterborne pathogens. The purpose of this study was to investigate the effect of wildlife access on irrigation water used in the cultivation of Chinese cabbage in Goesan. The frequency of wild animals access to upstream water source and the contamination level of bacteria such as Escherichia coli and Enterococci of irrigation water used in Chinese cabbage farm was examined. A total of 37 wildlife including the wild bear and water deer were observed in upstream of water source during the cultivation of Chinese cabbage. The result indicated the presence of hygienic indicator bacteria from the upstream where there is no human access. The contamination range of coliforms, E. coli, and Enterococcus spp. Detected in the irrigation water were 2.13~4.32 log MPN / 100 mL, 0.26~2.03 log MPN / 100 mL, and 1.43~3.49 log MPN / 100 mL, respectively. Due to low water temperatures, the contamination levels of coliform bacteria and E. coli in the irrigation water during harvesting time was lower compared to those recorded during transplanting of Chinese cabbage. However, no significant difference was detected in the number of Enterococci during the cultivation of Chinese cabbage. The results indicated the need to manage the microbial risk in irrigation water to enhance safety in cultivation of Chinese cabbage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.4
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• pp.294-303
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• 2018

To set an optimal harvest time for five main whole-crop silage (WCS) rice cultivars, Nokyang (Ny), Mogwoo (Mw), Mogyang (My), Nokwoo (Nw) and Yeongwoo(Yw), based on feed value and dry matter yield, we analyzed water content (WC), feed values such as percent crude protein (CP), crude fat (CF), crude ash (CA), neutral detergent fiber (NDF), acid detergent fiber (ADF), estimated total digestible nutrients (TDN), and calculated their dry matter yield (DMY). These parameters were estimated at the booting stage and every 10 days from start of heading to 45 days after heading (DAH) to identify the optimal harvest time for these rice varieties. In all varieties, except Ny, the WC was about 65% on the $30^{th}$ DAH. In terms of WC, it is judged that there would be no major problem in preparing high quality silage when harvested between 20~30 DAH for Ny and about 30 days for the other cultivars. The CP and CA decreased significantly as the harvest time was delayed in all varieties (p<0.05). However, the CF in the tested varieties generally declined as DAH increased, and then increased again(p<0.05). The decrease in ADF and NDF was significantly different from the booting stage to 45 DAH in all varieties (p<0.05) and the estimated TDN increased gradually in all varieties as the harvest time was delayed. The TDN of all varieties, except Nw, was over 70% around 30 DAH. As harvest time was delayed, the DMY for all WCS rice increased significantly (p<0.05). The maximum DMY for each cultivar was observed at 45 DAH, however, no significant difference (p<0.05) was seen after 40 DAH for Ny and Yw, 30 DAH for Mw and Nw, and 20 DAH for My. Considering these results and others factors such as lodging, shattering, digestibility of grains, conversion of eating rice, etc., the optimal harvest time for silage use of all WCS rice tested was generally the yellow ripening stage, at about 30 DAH (30~40 DAH for Ny and Mw, and 30 DAH for My, Nw and Yw).

• Journal of Korean Society of Forest Science
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• v.108 no.1
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• pp.29-39
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• 2019

The objective of this study was to suggest a suitable amount of fertilizer using the changes in growth performances and soil properties for improving survival and quality of Zelkova serrata trees in a harvested Pinus rigida plantation. One-year-old containerized seedlings of Z. serrata were planted with the density of 3000 seedlings $ha^{-1}$ in end of March 2011 at Gwangneung experimental forest, Pocheon. Solid compound fertilizer (N:P:K=3:4:1) were applied yearly in three amounts (control: no fertilization, F1: $180kg\;ha^{-1}$, and F2: $360kg\;ha^{-1}$) every May from 2011 to 2013. We analyzed soil properties before (2011) and after (2012 and 2017) fertilization. And we measured the root collar diameter and height of Z. serrata trees from 2011 to 2016, and then calculated H/D ratio and stem volume. Soil properties at Z. serrata plantation did not show difference according to fertilization level in every investigation year. As time passed after planting, however, concentrations of total nitrogen and available phosphorus were increased from decreased. The growth of root collar diameter, height and stem volume of Z. serrata trees at F2 plot were significantly higher those at the other plots after only 2 years of fertilization. Because Z. serrata tree demand to more nutrient during the early growing period. The survival rate of Z. serrata trees at control plot was significantly lower than that at the other plots. This might be due to Z. serrata trees at control plot had not the upper hand from competition with vegetation at the early in planting. However, the growth of height and stem volume of Z. serrata trees between F1 and F2 plots did not show difference over 6 years after planting. Consequently, we could suggest that Z. serrata trees need to F1 fertilization level for considering improving survival and quality of Z. serrata trees and economical efficiency of plantation managements after harvesting P. rigida plantation.

• Journal of the Korean Applied Science and Technology
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• v.36 no.1
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• pp.324-332
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• 2019

Most countries including Korea and Indonesia have strong policy for implementing biofuels like biodiesel. Shortage of the oil feedstock is the main barrier for increasing the supply of biodiesel fuel. In this study, in order to improve the stability of feedstock supply and lower the biodiesel production cost, the feasibility of biodiesel production using two types of Indonesian tropical crop oils, pressed at different harvesting times, were investigated. R. Trisperma oils, a high productive non-edible feedstocks, were investigated to produce biodiesel by esterification and transesterification because of it's high impurity and free fatty acid contents. the kindly provided oils from Indonesia were required to perform the filtering and water removal process to increase the efficiency of the esterificaton and transesterification reactions. The esterification used heterogeneous acid catalyst, Amberlyst-15. Before the reaction, the acid value of two types oil were 41, 17 mg KOH/g respectively. After the pre-esterification reaction, the acid value of oils were 3.7, 1.8 mg KOH/g respectively, the conversions were about 90%. Free fatty acid content was reduced to below 2%. Afterwards, the transesterification was performed using KOH as the base catalyst for transesterification. The prepared biodiesel showed about 93% of FAME content, and the total glycerol content was 0.43%. It did not meet the quality specification(FAME 96.5% and Total glycerol 0.24%) since the tested oils were identified to have a uncommon fatty acid, generally not found in vegetable oils, ${\alpha}$-eleostearic acid with much contents of 10.7~33.4%. So, it is required to perform the further research on reaction optimization and product purification to meet the fuel quality standards. So if the biodiesel production technology using un-utilized non-edible feedstock oils is successfully developed, stable supply of the feedstock for biodiesel production may be possible in the future.

• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.166-171
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• 2019

This study was conducted to investigate the effect of gaseous chlorine dioxide ($ClO_2$) concentration and treatment method for maintaining marketability in strawberries 'Maehyang' for export. After harvesting strawberry colored with $60{\pm}5%$ of the skin, and the gaseous $ClO_2$ was applied as four treatments in the cold store set with $10^{\circ}C$ which were as follows: i) non-treatment (Control), ii) $0.2mg{\cdot}L^{-1}$ for 30 minutes, iii) $0.4mg{\cdot}L^{-1}$ for 30 minutes, and iv) continuously exposed at $0.4mg{\cdot}L^{-1}$ during the storage period. Weight loss, firmness, soluble solids content, color, incidence of gray mold, and quality grade of strawberries were investigated every 3 days during 16 days storage in cold store. The weight loss was consistently high at $0.2mg{\cdot}L^{-1}\;ClO_2$ treatment, and the weight loss was lower than other treatments when gaseous $ClO_2$ was continuously treated. Firmness was significantly higher at 0.2 and $0.4mg{\cdot}L^{-1}$ $ClO_2$ treatment on the 13th day of storage. Soluble solids content tended to below in continuous gaseous $ClO_2$ treatment. The colors showed no tendency as affected by concentrations and treatment methods of gaseous $ClO_2$. No gray mold was observed in the continuous gaseous $ClO_2$ treatment until the 13th day of storage. The quality grade was lower in gaseous $ClO_2$ treatment group than in the control. As a result, it was possible to decrease the weight loss and the incidence of gray mold by continuously treating the gaseous $ClO_2$ to strawberry 'Maehyang' for export during the storage period after harvest. However, further research is needed on method to maintain quality grades of fruits.

• Journal of Korean Society of Forest Science
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• v.110 no.2
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• pp.254-265
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• 2021

As a result of measuring the polyphenol content of Humulus japonicus (HJ) extract according to the collection time and extraction solvent, bothhot water extract and 70% ethanol extract were collected and extracted in June, and the polyphenol content was high. When the harvesting time was the same, the polyphenol content of the ethanol extract was higher than that of the hot water extract. As a result of measuring the antioxidant activity of HJ extract by measuring electron-donating ability, SOD-like activity, and ABTS radical scavenging ability, HJ6E, which has the highest polyphenol content, showed the highest activity. In addition, in the case of the extract collected in August, the polyphenol content was similar. However, the antioxidant activity of the ethanol extract was high, sothe antioxidant activity remained high when extracted with 70% ethanol. As a result of measuring tyrosinase inhibitory activity for evaluating skin whitening activity, HJ6W did not show any activity. The activity at the highest concentration was 16.18% for HJ8W, 8.07% for HJ6E, and 14.7% for HJ8E. Therefore, the content of ingredients showing skin whitening activity was higher in August than in June. In the elastase inhibitory activity for evaluating the anti-wrinkle activityof the skin, the ethanol extract showed very little activity, and the hot water extract did not. In addition, since all extracts do not show astringent activity, it is judged that it is not appropriate to use HJ as a functional ingredient for preventing wrinkle formation. As a result of measuring the cell viability of HJ6E, which showed the highest polyphenol content and antioxidant activity, it showed a cell proliferation effect at low concentrationsbut strong cytotoxicity at concentrations above 50 ㎍/mL. In the case of the NO production inhibitory ability, as the concentration increased, the NO production of Raw 264.7 was suppressed. Theamount of NO production at 1,000 ㎍/mL decreased to 40.7%. However, whether these results are due to cytotoxicity or the extract's efficacy is a part that requires further research.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.3
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• pp.165-175
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• 2019

In response to elevated temperature, a shift in the rice planting period was proposed as a promising option in temperate regions. To understand the yield response of early maturing rice to different transplanting dates and to analyze the related agronomic traits in the central plain area, we performed a two-year study using different transplanting dates and six varieties in Suwon, Korea. The maximum head rice weight was achieved in the treatments transplanted between June 14 and 29, depending upon the varieties. The optimal mean temperature during the 40 days from heading stage for attaining the maximum head rice weight was $21.8^{\circ}C$ on the average of six varieties. The index of head rice weight was positively correlated with the indices of both the milled rice weight and head rice percentage, the latter showing a higher coefficient of determination. The highest milled rice weight was commonly achieved from the treatment transplanted on June 29, where the head rice weight was also the highest. The index of milled rice weight was significantly correlated with the indices of grain filling percentage and number of spikelets per area, but not correlated with the index of 1000-brown rice weight. The transplanting date with the highest milled rice yield produced the largest number of spikelets per area, greatest biomass at the heading and harvesting stages, and highest level of harvest index. We suggest that the optimal transplanting date for early maturing rice varieties in the central plain area is from June 14 to 29. High head rice yield in this study was attributed to increased spikelets owing to the increased biomass production at the heading stage, enhanced grain filling due to the high biomass production and harvest index at maturity, and improved head rice percentage.

• Journal of Mushroom
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• v.18 no.4
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• pp.398-402
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• 2020

This study was conducted to set up a proper replacement cycle of High Efficiency Particulate Air (HEPA) filters by observing the microbial populations in the air of the cultivation house of Pleurotus eryngii, before and after HEPA filter replacement at different periods. The density of bacteria and fungi in the air during each cultivation stage was measured using a sampler before the replacement of the HEPA filter. The results showed that airborne microorganisms had the highest density in the mushroom medium preparation room, with 169.7 CFU/㎥ of bacteria and 570 CFU/㎥ of fungi, and the removed old spaun had 126.3 CFU/㎥ of bacteria and 560 CFU/㎥ of fungi. The density of bacteria and fungi in the air at each cultivation stage before the replacement of the HEPA filter was 169.7 CFU/㎥ and 570 CFU/㎥, and 126.3 CFU/㎥ and 560 CFU/㎥, during the medium production and harvesting processes, respectively. After the replacement of the HEPA filter, the bacterial density was the lowest in the incubation room and the fungal density was the lowest in the cooling room. The microbial populations isolated at each period consisted of seven genera and seven species before the replacement, including Cladosporium sp., six genera and six species after 1 month of replacement, including Penicillium sp., 5 genera and 7 species after 3 months of replacement, including Mucor plumbeus, and 5 genera and 12 species, 5 genera and 10 species, and 5 genera and 10 species, 4, 5, and 6 months after the replacement, respectively, including Penicillium brevicompactum. During the period after replacement, the species were diversified and their number increased. The density of airborne microorganisms decreased drastically after the replacement of the HEPA filter. Its lowest value was recorded after 2 months of replacement, and it increased gradually afterwards, reaching a level similar to or higher than that of the pre-replacement period. Therefore, it was concluded that replacing the HEPA filter every 6 months is effective for reducing contamination.

• Journal of The Korean Society of Grassland and Forage Science
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• v.41 no.2
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• pp.96-101
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• 2021

This study was conducted to determine the effect of horse manure compost application on Italian ryegrass (IRG) yield and volcanic ash soil characteristics. Because the number of horses in Korea is growing, the amount of horse manure is growing. Jeju island, where about 55 % of the horses live, is composed of volcanic ash soil. This study was conducted for about 7 months. Sowing was conducted on October 2019. Harvesting was conducted at heading stage(2020.5.). Five treatments were established based on the horse manure compost composition. These were 100 % chemical fertilizer (CF), the combination of 50 % horse manure and 50 % chemical fertilizer (combination), horse manure with 50 % nitrogen (HM 50 %), horse manure with 100 % nitrogen (HM 100 %), and horse manure with 150 % nitrogen (HM 150 %). The plant height and dry matter yield were investigated to determine the forage yield and the soil characteristics of pH, total nitrogen, available phosphate, and organic matter were analyzed. The plant heights in the CF, combination, and HM 150 % treatments were 147.8 cm, 144.3 cm, and 147.1 cm respectively (Table 2). Dry matter yield in the CF treatment was about 23,807 kg/ha, which tended to be the highest dry matter yield. HM 150 % and the combination treatment were about 18,804 and 18,455 kg/ha, respectively, which tended to be the highest dry matter yield of the treatments amended with horse manure compost. The dry matter yield of the HM 100 % and HM 50 % treatments was about 15,801 kg/ha and 14,446 kg/ha, respectively (Table 2). The pH of the surface soil tended to increase after the experiment. The soil pH of the HM 150 % treatment was significantly higher than the soil pH of the other treatments. The pH was affected by the amount of horse manure compost, with a pH of 8.1. The available phosphate in the treatments in which horse manure compost was added was higher than the available phosphate in the CF treatment. And the available phosphate in the HM 150 % treatment was significantly higher than the available phosphate in the other treatments (p < 0.05)(Table 3). These results suggest that 50 % horse manure should be applied to IRG as the basal fertilizer and the remaining 50 % should be chemical fertilizer as the top fertilizer. This can provide the proper IRG dry matter yield with less effect on volcanic ash soil.