• Journal of Food Hygiene and Safety
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• v.21 no.2
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• pp.52-59
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• 2006

This survey was conducted to monitor the current status of pesticide residues in imported agricultural products circulated in Gwangju, 2005. A total of 108 samples was analyzed by multiresidue method. Of these samples, 32 were citrus fruits, 60 were tropical fruits and grapes, and 16 were vagetables. The origin was Philippine for 39 samples, U.S.A. for 36, China for 12, New Zealand for 11, Chile for 6, etc. The overall rate of detections was 30.6% and no samples had violative residues. Of citrus fruits,20 samples (62.5%) had residues and the residues were thiabendazole, imazalil, chlorpyrifos, etc. Of tropical fruits and grapes, 13 samples (12.0%) had residues and the residues were azoxystrobin, chlorpyrifos, carbendazim, captan, etc. 16 of vagetables had no detectable pesticide residues. Thiabendazole (71% in oranges and 56% in grapefruits) and imazalil (50% in oranges) were found in citrus fruits, which were frequently used as post-harvest pesticides. And azoxystrobin which is one of strobilurin fungicides, was often detected in mango, tropical fruit(27%).

• Korean Journal of Medicinal Crop Science
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• v.10 no.5
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• pp.419-422
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• 2002

Korean angelica(Angelica gigas Nakai), a oriental medicinal plants is important and in great demand in Korea. This crop is a biennial which is to die after flower, so as could not harvest the root. A new variety 'Anpung' was developed from the selection of the local collecting population by medicinal crop team at NCES in 2001. This showed stable bolting during its cropping year and have high quality and yield potential. The color is greenish purple in stem and red purple in flower. It was longer in plant height and root length, thicker in root diameter, more leave and latheral roots comparing with the check variety 'Manchu'. The dry root was 72 g/plant showing heavier than check variety of 65 g/plant. It showed such low bolting rate as 0.5%, on the other hand 49.3% in landrace when it cultured by transplanting with heating nursery seedlings, and $0{\sim}15%$ with field nursery seedlings. The dry root yield of the variety was averaged 3,630 kg/ha out yielding the check variety by 11% at the three regional yield test from 1999 to 2001. Finally, 'Anpung' showed higher content of extracts up to 46.3% in 'Anpung' and 45% in check variety, decursin and decursinol contents was 3.48% and 2.79%, showing slightly higher than check variety.

• Journal of Mushroom
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• v.10 no.3
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• pp.129-135
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• 2012

This study was carried out to investigated optimum mixing ratio of Korean natural Cudrania tricuspidata for production of functional oyster mushroom. Total nitrogen and carbon source of Cudrania tricuspidata was 0.27% and 40.9%, respectively and C/N ratio was 152. Total nitrogen source and pH of substrates mixed with Cudrania tricuspidata were 2.7~2.8 and 4.9~5.1, respectively. The contents of $P_2O_5$, CaO, MgO and $Na_2O$ were no significant difference. Mycerial growth was faster at Cudrania tricuspidata 10% than that of control, but the other treatment was slower. Yields of fruiting body was the highest at Cudrania tricuspidata 20%, and diameter and thick of pileus were no significant difference to increase of Cudrania tricuspidata addition ratio. The L value of pileus was the highest at the Cudrania tricuspidata 20% during mushroom harvest, but there was no significant difference in the a-value and the b-value. Chemical contents of fruiting body were the highest at the Cudrania tricuspidata 30%.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.14 no.1
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• pp.77-88
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• 2011

This study was carried out to investigate the effects of soil depth and planting density on the growth of lettuce, crown daisy, and strawberry on a rooftop condition using artificial soil as a growth media. The vegetable crops showed better growth for plant height (cm), plant width (cm), plant fresh weight (g), and Fo, Fm and Fv/m on 20cm depth soil than 10cm depth soil except strawberry. Planting density of $16/m^2$ and $64/m^2$ did not show significant differences on the growth of the crops. Soil moisture content and EC were low for 10cm depth soil in lettuce plots, whereas there was no significant differences on soil moisture and EC between two soil depth in strawberry plots. Hunter's L, a, and b values showed the leaf color of lettuce dark green on 20cm depth soil and reddish on 10cm depth soil. Results showed that soil depth suitable for crop growth on rooftop conditions was 20cm rather than 10cm. Growth response of the crops showed no significant difference between $16/m^2$ and $64/m^2$, indicating that planting density of 64 $plants/m^2$ could be practiced on rooftop conditions. Lettuce growth rapidly changed in control treatment in which leaves were not pinched out, while slowly changed in plants which leaves were periodically pinched out. In the case of control plot, it was impossible to harvest because withering of lower leaves after blossom on June 22. The plant of crown daisy in which pinching was not conducted, blossomed on June 7, and the plants were removed since its aesthetical value was lost. Strawberry seemed to be a suitable vegetable crop for rooftop conditions based on its high covering rate and extended growth period until late October. The soil depth 20cm and planting density 64 $plants/m^2$ were suitable for vegetable crops on green roof system using artificial soil.

• Journal of the Korean Society of Industry Convergence
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• v.20 no.5
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• pp.395-404
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• 2017

Cultivating soybeans in rice paddy field reduces labor costs and increases the yield. Soybeans, however, are highly susceptible to excessive soil water in paddy field. Controlled drainage system can adjust groundwater level (GWL) and control soil moisture content, resulting in improvement soil environments for optimum crop growth. The objective of this study was to fit the soybean growth data (canopy height and stem diameter) using Gompertz model and Logistic model at different GWL and validate those models. The soybean, Daewon cultivar, was grown on the lysimeters controlled GWL (20cm and 40cm). The soil textures were silt loam and sandy loam. The canopy height and stem diameter were measured from the 20th days after seeding until harvest. The Gompertz and Logistic models were fitted with the growth data and each growth rate and maximum growth value was estimated. At the canopy height, the $R_2$ and RMSE were 0.99 and 1.58 in Gompertz model and 0.99 and 1.33 in Logistic model, respectively. The large discrepancy was shown in full maturity stage (R8), where plants have shed substantial amount of leaves. Regardless of soil texture, the maximum growth values at 40cm GWL were greater than the value at 20cm GWL. The growth rates were larger at silt loam. At the stem diameter, the $R_2$ and RMSE were 0.96 and 0.27 in Gompertz model and 0.96 and 0.26 in Logistic model, respectively. Unlike the canopy height, the stem diameter in R8 stage didn't decrease significantly. At both GWLs, the maximum growth values and the growth rates at silt loam were all larger than the values at sandy loam. In conclusion, Gompertz model and Logistic model both well fit the canopy heights and stem diameters of soybeans. These growth models can provide invaluable information for the development of precision water management system.

• Journal of The Korean Society of Grassland and Forage Science
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• v.20 no.3
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• pp.199-206
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• 2000

This experiment was conducted to evaluate the effect of winter forage rye and green manure hairy vetch on soil mineral nitrogen and corn nitrogen uptake. Soil nitrate at corn seeding decreased slightly with cultivation of winter rye, but soil nitrate did not decreased by cultivation of winter hairy vetch. Soil nitrate nitrogen increased 60~70 kgN/ha higher by hairy vetch green manure than winter rye and fallow at 6-leaf and harvest stage of corn, respectively, and much soil nitrate nitrogen such as 85, 125 kgN/ha was remained at N fertilizer 100, 200 kgN/ha of hairy vetch green manure at harvesting time, respectively. Corn yield was not different among treatments of winter crop and N rate, but nitrogen concentration of corn stover increased by hairy vetch green manure. Increase of total corn nitrogen uptake by hairy vetch green manure was 50~60 kgN/ha compared with winter rye and fallow. It is thought that basal fertilizer nitrogen 100 kgN/ha could be reduced by hairy vetch green manure in considering soil nitrate and nitrogen uptake at harvesting time.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.4
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• pp.359-365
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• 2011

This study was conducted to investigate the production, elver stocking, rearing facilities and rearing method of eel culture to determine aquaculture management conditions for optimal rearing of eel Anguilla japonica. The production of eel culture was evaluated by the proportion of eels from the main inland fin fish species production in Korea. Elver stocking was assessed by the elver stocking densities of pond and recirculation culture. Rearing facilities were investigated according to the rearing tank size proportion of the pond and recirculation culture. We selected sample farms by region and by size. We visited sample farms and recorded the number of elvers stock for pond area, size of tanks, feed and feed quantity, and the size and number of harvest eels. The production capacity of Jeollanam-do and Jeollabuk-do were 71.9% and 21.3% respectively. This production quantity represented 93.2% of the total Korean eel production quantity. In Jeollanam-do, there are 236 eel farms, 202 pond farms, and 34 recirculation aquaculture facilities. The elvers' first density data by each aquaculture method revealed that elvers' first density varied more in recirculation system farms, as compared to pond aquaculture. In intensive pond farms, the elvers' first density decreased as the size of farm increased. There was a correlation between the size of tank(x) and the facility of a water wheel for dissolved oxygen in pond culture systems(y=0.022x-0.494; $R^2$=0.860). Another strong correlation was found between the weight of eel(x) and eel density(y) in pond culture systems(y=283.5x-0.27; $R^2$=0.992). Finally, there was a strong correlation between the length of eel(x) and the weight of eel(y) in intensive pond culture(y=0.0005x-3.2783; $R^2$=0.9775). The final survival rate did not differ significantly among pond sizes and culture types.

• Journal of Bio-Environment Control
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• v.20 no.2
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• pp.156-161
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• 2011

This experiment was performed in order to define the characteristic and quality of the fruits set on primary and secondary shoots in 'Heukgoosul' grape. The numbers of flower clusters per shoot were 1.1 and 0.6 in primary shoots and secondary shoots, respectively. The fruits of primary shoot showed 12.1 g of higher berry weight than 8.9 g of the fruits set on secondary shoots. Fructose and glucose contents were significantly higher in the fruits of secondary shoots during veraison, but the levels gradually decreased, reaching a similar level with those of primary shoot at the harvest stage. The acid content decreased rapidly from day 50 after full bloom in both primary and secondary shoots, but the rate of decrease slowed down from day 70 after full bloom in secondary shoots. Berries of secondary shoots showed rapid increase of skin coloration during veraison and reached a high degree of coloration within a short period when compared with those of primary shoots.

• Journal of Bio-Environment Control
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• v.22 no.3
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• pp.256-261
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• 2013

The spacing between plug cells and cell volume of each plug cell for nursing tomato seedlings were studied to know the effects on seedling growth and early yield. There were four treatments. The spacing of plug cells was done (OK) or not (NO) in case of cell spacing. The cell number in a plug tray was set to 40 or 50 in case of cell volume. The growth environment and irrigation regime were the same in all of the treatments during the experiment period. The photosynthetic rates, seedling qualities, yield and yield speed were significantly affected by both of the treatments. The photosynthetic rates and seedling qualities were the best in 40S-OK following by 50S-OK, 40S-NO, and 50S-NO while the yield was the best in 40S-OK following by 40S-NO, 50S-OK, 50S-NO. It means the spacing gives more impact than the cell volume in the stage of nursing but the cell volume gives more impact than the spacing after the stage of nursing. In the conclusion the spacing of plug cells in appropriate nursing stage is needed with the appropriate cell volume to make high quality of seedlings and high yield.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.1094-1099
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• 2012

Green manure cultivation affects soil productivity and nutrient conservation in paddy soil at winter season. This study was to evaluate nitrogen behavior released from chinese milk vetch (CMV) as green manure by using stable $^{15}N$ trace during rice cultivation. The CMV used in the experiment was 29.9 of C/N ratio and 14.1 g N $kg^{-1}$ ($^{15}N$ 0.388 atom % excess) and was applied at rates of 10 and $30Mg\;ha^{-1}$ in pot of 1/2000a size. Rice growth and N uptake increased with higher levels of CMV application at harvesting stage. Among total N uptake, 14.6 and 26.8 % of nitrogen was released respectively from the two different rates of CMV application. Stable $^{15}N$ recovery by rice biomass was 60%, 54% to the $^{15}N$ input, respectively, of CMV application, which decreased in order of grain, root, and straw of rice biomass. Total N content in the soil after rice harvest was 1.9 and 2.1 g N $kg^{-1}$, respectively, with increasing N input by the different rates of CMV application and the rate of $^{15}N$ recovery derived from CMV in the soil was 3.8 and 4.8 %, respectively. N input by CMV application induced rice growth and productivity during rice cultivation. However, it might need proper managements to reduce N loss because about 36-41 % of nitrogen was lost from N input by CMV application.