• Korean Journal of Environmental Agriculture
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• v.32 no.1
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• pp.84-93
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• 2013

BACKGROUND: This study was carried out to investigate the residual characteristics of insecticides used for Oriental Tobacco Budworm control and to establish the recommended pre-harvest residue limit leading to contribution in safety of paprika production. METHODS AND RESULTS: The recommended Pre-Harvest Residue Limits (PHRLs) of insecticides during cultivation of paprika were calculated from residue analyses of insecticides in fruits 1, 3, 5, 7, 10, 12, 15, 18 and 21 days after treatment. Paprika samples were extracted with QuEChERS method and cleaned-up with amino propyl SPE cartridge and PSA, and insecticide residues were analyzed either by HPLC/DAD or GLC/ECD. The limits of detection were 0.01 mg/kg for 5 insecticides. Average recoveries were $81.3{\pm}1.62%$-$98.3{\pm}1.58%$ of 5 insecticides at fortification levels of 0.1 and 0.5 mg/kg. The biological half-lives of the insecticides were 8.5 days for bifenthrin, 11.8 days for chlorantraniliprole, 16.8 days for chlorfenapyr, 7.1 days for lamda-cyhalothrin and 31.3 days for methoxyfenozide at recommended dosage, respectively. CONCLUSION(S): The pre-harvest residue limits for 10 days before harvest were recommended 1.05 mg/kg, 1.41 mg/kg, 0.93 mg/kg, 2.06 mg/kg and 1.08 mg/kg as bifenthrin, chlorantraniliprole, chlorfenapyr, lamda-cyhalothrin and methoxyfenozide, respectively. This study can provide good practical measures to produce safe paprika fruit by prevention of products from exceeding of MRLs at pre-harvest stage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.4
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• pp.337-342
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• 2012

This study was conducted to evaluate the weed suppressing effects of different cropping system including hairy vetch and rye cover crops, polyethylene plastic film, and transplanting film mulching in direct sowing and transplanted foxtail millet field in 2011. Crop growth and development and weed occurrences in the fields were examined to know the efficiency of proposed cropping system. In polyethylene film mulching treatment, heading date of foxtail millet was earlier by 4 days than control, on the other hands, rye cover crop mulching delayed heading date by 8 days. Besides the effect of cover crop on the heading of foxtail millet, the residues changed growth characteristics. Plant height of foxtail millet was increased by 92.4% at hairy vetch treatment although the height of was reduced by 63.7% in the rye cover crop treatment. Hairy vetch treatment showed beneficial effects on foxtail millet growth reduced the occurrences of grasses and broadleaf weeds higher than 90%, as compared to control in foxtail millet fields. While rye cover crop treatment showed poor foxtail millet growth reduced less strongly grasses and broad-leaf weeds by 47% and 90%, respectively. At harvest, yield of foxtail millet was greater in order of hairy vetch cover crop > polyethylene film mulching > rye cover crop ${\fallingdotseq}$ control in both transplanted and direct sown fields.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.4
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• pp.407-410
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• 1992

Changes in the concentrations of six low-molecular-weight organic acids extracted from hydrolysates of plant residues undergoing decomposition for 90 days under the laboratory condition were investigated. 1. Litters of deciduous and coniferous trees and wild grass cuttings were sampled for the study and concentrations of formic, acetic, succinic, tartaric, malic and citric acids were determined. The concentration of malic acid were negligible. 2. In the wild grass cuttings, the total concentration of low-molecular-weight organic acids decreased with the passage of decomposition. Monocarboxylic acids, I. e., formic and acetic acids, predominated over dicarboxylic and tricarboxylic acids. Formic and acetic acids appeared to be compensatory for each other. Concentration of citric acid increased at a remarkable rate. 3. The total concentration of organic acids in the hydrolysates of deciduous litter was shown to increase. The concentration of monocarboxylic acids was significantly higher in the end of the period of decomposition. Here again a compensatory relationship was observed between concentrations of formic and acetic acids. 4. There was comparatively little change exhibited during the period of experiment concerning the concentrations of organic acids from hydrolysates of decomposing coniferous litter. In contrast with the others, however, the concentration of succinic acid, a dicarboxylic acid, maintained the highest level.

• Journal of Applied Biological Chemistry
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• v.61 no.1
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• pp.75-78
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• 2018

Ethephon is useful pesticide as ethylene precursor, which is an efficient plant hormone to produce functional secondary metabolites. However, the residual safety of ethephon was not studied on various crops. In here, the dissipation pattern of ethephon residue in soybean leaf was investigated both on the foliar and drenching applications. The biological half-lives of ethephon residues were 26.6, and 21.1 h on the once, and double foliar applications, respectively. Although the residue after three days from the final application was up to $60.6mg\;kg^{-1}$, the residue was below the limit of quantitation on the dried soybean leaf. In addition, drenching application of ethephon could increase the residue up to $36.3mg\;kg^{-1}$ after 20.1 h from the application, however, the treatment would not affect to the total phenol content significantly (p >0.01).

• Journal of Applied Biological Chemistry
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• v.61 no.2
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• pp.191-194
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• 2018

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) are emerging pollutants in agricultural product, and the residual patterns and the uptake potentials were only studied on several crops, not on rice. The residue level and bioconcentration factor (BCF) of PFOA and PFOS were investigated on the low ($1mg\;kg^{-1}$) and the high contaminated soil ($5mg\;kg^{-1}$) groups. The residue levels in brown rice in the low group and in the high group were 0.002-0.004 and $0.008-0.030mg\;kg^{-1}$ of the each perfluorinated compounds (PFCs), and in the rice husk were $0.035-0.074mg\;kg^{-1}$ and $0.125-0.376mg\;kg^{-1}$ of the each PFCs, respectively. Furthermore, the residues in rice straw were the highest level in the all rice parts both in the groups. The PFOA and PFOS were reached to $3.723mg\;kg^{-1}$ and $7.641mg\;kg^{-1}$, respectively, and the BCF (1.474 and 4.700) as well.

• Journal of Environmental Impact Assessment
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• v.24 no.1
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• pp.1-15
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• 2015

To mitigate the impacts of climate change on agricultural ecosystems, development of agricultural management for enhanced soil carbon sequestration is required. In this study, the effects of fertilizer types (chemical fertilizer and manure compost), cropping systems, and crop residue management on SOC(Soil Organic Carbon) sequestration were investigated. Summer corn and winter barley were cultivated on experimental plots under natural rainfall conditions for two years with chemical fertilizer and manure compost. Soil samples were collected conducted and analyzed for SOC for soil. To estimate long-term variation patterns of SOC, DNDC was run with the experimental data and the weather input parameters from 1981 to 2010. DNDC simulation demonstrated SOC reduction by chemical fertilizer treatment unless plant residues are returned; whereas compost treatments increased SOC under the same conditions and SOC increment was proportional to compost application rate. In addition, SOC further increased under corn-barley cropping system over single corn cropping due to more compost application. Regardless of nutrient input type, residue return increased SOC; however, the magnitude of SOC increase by residue return was lower than by compost application.

• The Korean Journal of Pesticide Science
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• v.20 no.4
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• pp.341-348
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• 2016

Residual patterns of fungicides fludioxonil and metconazole applied 2 or 3 times on wheat were investigated with consideration for their distribution rates in each compartment of wheat. Wheat samples collected at harvesting day were divided into three compartments such as grain, hull and straw, and the pesticide residue analysis was individually carried out to such compartments of wheat. The analytical methods of fungicide residues in wheat were acceptable, with recoveries of 84.3 to 113.3% and correlation coefficients of 0.1 to 4.7%. Due to the systemic characteristics, the residual amounts of metconazole in the grain part of wheat were greater as 0.13~0.17 mg/kg than those amounts (0.01-0.03 mg/kg) for fludioxonil. To absolute residue amounts of the fungicides in one wheat plant, their distribution rates in each compartment of wheat were the highest in straws (68.5-70.7%), followed by hulls (29.0-31.0%) and grains (0.2-0.8%).

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.4
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• pp.11-20
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• 2016

Depletion of natural resources and reduction of greenhouse gas emissions are an important issue which we have to solve. The recycling of waste has emerged as a global concern. In Korea, the development of cost-effective treatment and recycling technologies also need to be improved. In this study, we compared and analyzed the cost per unit of treatment and recycling of organic waste, and presented an effective recycling scheme. We investigated the current status of treatment and costs for six types of organic wastes from 80 workplaces, including organic wastewater treatment sludge, processed organic sludge, and plant residues. In addition, environmental costs for greenhouse gas reduction were calculated. It's an economic way that organic waste is composted and used as cement additives. In particular, the economic analysis was done by realistic results of the survey target companies. In conclusion, in order for reliable processing and recycling of organic wastes, wastewater treatment sludge and sewage sludge need to be classified based on hazard characteristics. Finally, technical difficulties need to be further resolved such as odors, leachate, and debris on recycling organic wastes.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.4
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• pp.371-377
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• 1996

Utilization of crop residues was investigated in search of ecologically desirable treatment of wastewater from small-scale swine farm. Instead of common materials rice stray was used as a support medium of tricking filter with the farm, wastewater treatment. The treated rice stave medium was dried, crushed, and directly added to soil, where bunching lettuce seedlings were grown under greenhouse conditions. The development of bunching lettuce was significantly enhanced by the application of the straw medium up to 2100 kg/10a. Little changes in soil chemical properties were observed at harvesttime, except the pH which was raised by more than 1 unit, and the content of Mg which was depleted presumably by the uptake of the plant.

• Molecules and Cells
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• v.26 no.6
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• pp.536-547
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• 2008

Anthocyanidin synthase (ANS, leucoanthocyanidin oxygenase), a 2-oxoglutarate iron-dependent oxygenase, catalyzed the penultimate step in the biosynthesis of the anthocyanin class of flavonoids, from the colorless leucoanthocyanidins to the colored anthocyanidins. The full-length cDNA and genomic DNA sequences of ANS gene (designated as GbANS) were isolated from Ginkgo biloba for the first time. The full-length cDNA of GbANS contained a 1062-bp open reading frame (ORF) encoding a 354-amino-acid protein. The genomic DNA analysis showed that GbANS gene had three exons and two introns. The deduced GbANS protein showed high identities to other plant ANSs. The conserved amino acids (H-X-D) ligating ferrous iron and residues (R-X-S) participating in 2-oxoglutarate binding were found in GbANS at the similar positions like other ANSs. Southern blot analysis indicated that GbANS belonged to a multi-gene family. The expression analysis by real-time PCR showed that GbANS expressed in a tissue-specific manner in G. biloba. GbANS was also found to be up-regulated by all of the six tested abiotic stresses, UV-B, abscisic acid, sucrose, salicylic acid, cold and ethylene, consistent with the promoter region analysis of GbANS. The recombinant protein was successfully expressed in E. coli strain with pET-28a vector. The in vitro enzyme activity assay by HPLC indicated that recombinant GbANS protein could catalyze the formation the cyanidin from leucocyanidin and conversion of dihydroquercetin to quercetin, suggesting GbANS is a bifunctional enzyme within the anthocyanidin and flavonol biosynthetic pathway.