• Journal of the Korean Society of Food Science and Nutrition
• /
• v.41 no.11
• /
• pp.1508-1514
• /
• 2012

The purpose of this study was to evaluate the antioxidant contents and antioxidant activities of solvent fractions from methanolic extract of sericea lespedeza. To determine the antioxidant compounds in solvent fractions from methanolic extract, total polyphenolic, flavonoid, tannin, and proanthocyanidin contents were measured by spectrophotometric methods. Solvent fractions were evaluated for antioxidative capacity according to DPPH and ABTS radical scavenging activities. Total polyphenolic contents were 12.44, 3.61, 6.39, 27.11, 20.00, and 9.32 mg gallic acid equivalent (GAE)/g extract residue (ER), respectively. Total flavonoid contents were 2.94, 9.92, 7.77, 9.27, 5.11, and 2.66 mg catechin equivalent (CE)/g ER, respectively. Total tannin contents were 8.75, 10.04, 7.42, 17.32, 11.65, and 7.61 mg tannic acid equivalent (TAE)/g ER, respectively. Total proanthocyanidin contents were 346.09, 63.50, 103.76, 288.62, 231.99, and $358.48{\mu}g$ CE/g ER, respectively. DPPH radical scavenging activities of solvent fractions from methanolic extract of sericea lespedeza were 20.62, 5.16, 9.29, 20.80, 20.00 and 20.79 mg Trolox equivalent (TE)/g ER, and ABTS radical scavenging activities were 33.86, 9.24, 17.36, 33.76, 33.49, and 33.86 mg TE/g ER, respectively. SOD-like activities were 4.12, 0.61, 2.01, 9.89, 13.47, and 11.82 units/mL, and ${\alpha}$-glucosidase inhibition activities were 93.85 and 61.64% at concentrations of 50 and $25{\mu}g/mL$ in the water fraction, respectively. The results of this study show that notable antioxidant activities in sericea lespedeza have significant health benefits.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.66 no.4
• /
• pp.358-364
• /
• 2021

This study was conducted to select a desiccant and determine its concentration for safe usage to improve the harvesting efficiency of soybeans. Soybeans were treated with a desiccant (non-selective herbicide) before and after the maturation stage. The drying effect of the desiccant was higher at earlier treatment times than at the maturation stage, but the difference was not statistically significant. The higher efficacy might be related to the drying process of the leaves and stems, with most of the leaves and stems having already been dried by the time of hand harvesting. Desiccant treatments had no adverse effects on soybean yield, weight of 100 grains, seed quality, or seed germination rate compared with the untreated control. Pesticide residue analysis showed minimum residue concentration to be lower than the tolerance level of pesticide residues. In conclusion, it was confirmed that the desiccant was effective in drying soybean, and that there was no damage to the quality of soybean seeds. In addition to the drying effect, the dessicant treatment also facilitates the removal of weeds that interfere with the mechanical harvest and improves harvesting efficiency through the drying of the growth imbalanced individual. The desiccant treatment is expected to shorten the mechanical harvesting time by 1-2 weeks. It is thought that the selection of the proper cultivation period for other crops after soybean cultivation will be more advantageous.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.27 no.4
• /
• pp.340-360
• /
• 1982

Because of the continuing rapid increase in pesticide usage in Taiwan, much attention has been focus on pesticide contamination of food and effect of pesticides on human and environmental health. The Plant Protection Center (PPC) conducts safety evaluation of pesticides usee! in Taiwan. The pesticides are classified into different groups based on their acute toxicities. Pesticides which are classified into extremely toxic group are not allow to used on short term crops or the continuously harvest crops. The acute toxicity of pesticides to the beneficial insects are also studied, special attention has been paid to the two predators of rice brown planthopper. 60% of cultivated land in Taiwan are paddy field; therefore, acute fish toxicity was taken into consideration when a pesticide was applied for registration to be used in the paddy. Fish toxicities were evaluated by the dangerous rating value which is the amount of pesticide residue in the field water over the TLM value. Mutagenicity of pesticides was continuously evaluated by using Arne's microbial testing method. Island wide survey of residual levels of pesticides of known pollutants such as chlorinated hydrocarbon . insecticides, mercurial compounds in soil, water and biological samples were carried out constantly. The potential of a new1y Imported esticides to pollute the environment were studied by using model ecosystem. Ecological magnification (EM) of a chemical was calculated from model ecosystem. A chemical was considered as a pollutant when its EM value over 5000. In order to ensure the levels of pesticides residue of the crop within the safety limit. The 'tolerance' of pesticides on different crop groupings were established base on 1) acceptable daily intake value of individual pesticides, 2) average daily consumption of each crop groupings by Chinese person, 3) Actual residues of pesticides. on different crops obtained from supervised trials. Total about 79 pesticides for which the tolerances have been established on different crop groupings. Because the intensive agricultural system was adopted in Taiwan. The phytotoxicity of pesticides to the non-target crops was therefore become one of the important factor in the safety evaluation of pesticide usage. These will include 1) direct injury, 2) injury caused by pesticide polluted irrigation water, 3) injury caused by the pesticide polluted soil, 4) reduction of growth caused by the effect of pesticide on the soil microorganisms. This paper will reviewed all the aspects mentioned in the previous .paragraphs. Most the works have done in Taiwan by the PPC.y the PPC.

• Korean Journal of Weed Science
• /
• v.30 no.1
• /
• pp.34-42
• /
• 2010

Competitive ability, allelopathy, made the common ragweed (Ambrosia artemisiifolia var. elatior ) one of the most dangerous weeds in Korea. The aim of this research was to evaluate the role of common ragweed as test species under laboratory bioassay and glasshouse conditions. Inhibition effect of the leaf extract was higher than that of stem and root parts extracts on germination and seedling growth of weeds. The 5% concentration of leaf extract of common ragweed inhibited the germination rate of Echinochloa crus-galli, Digitaria sanguinalis and Cyperus microiria by 68.3, 74.6 and 87.3%, respectively, as compared to the control. Generally, increasing incorporation concentration inhibited seedling growth of weeds. Incorporation of 5% common ragweed residue significantly reduced the plant length of E. crus-galli, D. sanguinalis and C. microiria by 48, 63 and 68%, respectively, as compared to the control. Also, the values of dry weight were 72, 78 and 71%, respectively. Contrarily, the emergence rate of soybean and corn was not affected by the incorporation of 5% concentration of common ragweed residue. However, the dry weight was inhibited by 37 and 28%, respectively. These results suggest that common ragweed had the ability to control some weed species using toxic compounds like natural herbicide.

• Korean Journal of Environmental Agriculture
• /
• v.41 no.2
• /
• pp.108-114
• /
• 2022

BACKGROUND: This study was performed to determine residual characteristics of soil-treated metalaxyl-M and dinotefuran in crown daisy and to evaluate the risks from intake of the residual pesticides in the crop. METHODS AND RESULTS: The pesticide granules were treated in soil on two levels, and the plants samples were collected 51 days after seeding. The analytes were extracted and partitioned using the QuEChERS extraction packet (MgSO₄ 4 g, NaCl 1 g). The quantitative methods for metalaxyl-M and dinotefuran were validated in linearity, accuracy, and precision. Risk assessments of the pesticides were performed using Korea national nutrition statistics 2019. CONCLUSION(S): The residual concentrations of metalaxyl-M in crown daisy were 0.09-0.10 mg/kg (for the treatment at 6 kg/10 a) and 0.17-0.19 mg/kg (12 kg/10 a), respectively. The residual concentrations of dinotefuran in the crop were 0.53-0.75 mg/kg (3 kg/10 a) and 1.17-1.26 mg/kg (6 kg/10 a). The amounts of pesticides were less than MRL (Maximum Residue Limits) according to the Korean MFDS (Ministry of Food and Drug Safety). The HI (Hazard Index) of metalaxyl-M and dinotefuran for consumers was 0.0075% and 0.2250%, respectively. For females in the age between 50-64, the major consumer group, the HIs of the pesticides were <3%. Considering the consumption of crown daisy, they are not considered to be of toxicological concern.

• The Korean Journal of Pesticide Science
• /
• v.18 no.4
• /
• pp.321-329
• /
• 2014

This experiment was conducted to establish an analytical method for residues of amisulbrom, as recently developed an oomycete-specific fungicide showing inhibition of fungal respiration, in crops using HPLC-UVD/MS. Amisulbrom residue was extracted with acetonitrile from representative samples of five raw products which comprised apple, green pepper, kimchi cabbage, potato and hulled rice. The extract was diluted with 50 mL of saline water and directly partitioned into dichloromethane to remove polar co-extractives in the aqueous phase. For the hulled rice sample, n-hexane/acetonitrile partition was additionally employed to remove non-polar lipids. The extract was finally purified by optimized Florisil column chromatography. On an octadecylsilyl column in HPLC, amisulbrom was successfully separated from sample co-extractives and sensitively quantitated by ultraviolet absorption at 255 nm with no interference. Accuracy and precision of the proposed method was validated by the recovery test on every crop samples fortified with amisulbrom at 3 concentration levels per crop in each triplication. Mean recoveries ranged from 85.3% to 105.6% in five representative agricultural commodities. The coefficients of variation were all less than 10%, irrespective of sample types and fortification levels. Limit of quantitation (LOQ) of amisulbrom was 0.04 mg/kg as verified by the recovery experiment. A confirmatory method using LC/MS with selected-ion monitoring technique was also provided to clearly identify the suspected residue. The proposed method was sensitive, reproducible and easy-to-operate enough to routinely determine the residue of amisulbrom in agricultural commodities.

• Korean Journal of Environmental Agriculture
• /
• v.37 no.1
• /
• pp.57-65
• /
• 2018

BACKGROUND: An analytical method was developed using HPLC-UVD/MS to precisely determine the residue of flusulfamide, a benzenesulfonamide fungicide used to inhibit spore germination. METHODS AND RESULTS: Flusulfamide residue was extracted with acetone from representative samples of five raw products which comprised apple, green pepper, Kimchi cabbage, hulled rice, and soybean. The extract was diluted with large volume of saline water and directly partitioned into dichloromethane to remove polar co-extractives in the aqueous phase. For the hulled rice and soybean samples, n-hexane/acetonitrile partition was additionally employed to remove non-polar lipids. The extract was finally purified by optimized Florisil column chromatography. On an octadecylsilyl column in HPLC, flusulfamide was successfully separated from co-extractives of sample, and sensitively quantitated by ultraviolet absorption at 280 nm with no interference. Accuracy and precision of the proposed method was validated by the recovery experiment on every crop sample fortified with flusulfamide at 3 concentration levels per crop in each triplication. CONCLUSION: Mean recoveries ranged from 82.3 to 98.2% in five representative agricultural commodities. The coefficients of variation were all less than 10%, irrespective of sample types and fortification levels. Limit of quantitation (LOQ) of flusulfamide was 0.02 mg/kg as verified by the recovery experiment. A confirmatory method using LC/MS with selected-ion monitoring technique was also provided to clearly identify the suspected residue.

• Korean Journal of Environmental Agriculture
• /
• v.41 no.4
• /
• pp.236-244
• /
• 2022

BACKGROUND: Liquid fertilizers can provide nutrients to crops effectively and quickly. Amino acid liquid fertilizers produced by decomposing the residues of rendered livestock carcasses are expected to be effective in improving the productivity and quality of crops. METHODS AND RESULTS: The treatment conditions for maize cultivation were control (Cn), inorganic fertilizer (IF), inorganic fertilizer and rendering residue liquid fertilizer (IF+RALF), compost (CP), compost and rendering residue liquid fertilizer (CP+RALF). Crop productivity, sugar content, and nutrient uptake were investigated after maize harvest in the field applied with liquid fertilizers. Maize yields ranged from 87.6-158 g/plant, and the yield increased by 7.9% and 12.9% in IF+RALF IF+RALF and CP+RALF than in IF and CP, respectively. The maize sugar content increased in the range of 0.1-0.5 brix % by rendering residue liquid fertilizer (RALF) fertilization, and the sugar content was the highest in CP+RALF. There was no significant change in soil chemical properties of the soil due to liquid fertilizer treatment. CONCLUSION(S): RALF increased yield and sugar content in maize cultivation, and fertilization with organic fertilizers was more effective for maize cultivation than inorganic fertilizers. Residues of rendered livestock carcass can be recycled as amino acid fertilizers, which can be effectively used for crop production and quality improvement.

• Korean Journal of Soil Science and Fertilizer
• /
• v.43 no.6
• /
• pp.911-916
• /
• 2010

Rice paddy fields and crop residue burning are a major source of methane ($CH_4$) emissions, a potent greenhouse in agriculture. This study was conducted to assess $CH_4$ emissions in Korea cropland sector from 1990 to 2008. Greenhouse gas emissions from the cropland sector are calculated in two categories: 4C (Rice cultivation) and 4F (Field burning). In 4C: Rice Cultivation, methane emissions from paddy fields (continuously flooded and intermittently flooded) cultivated for rice production had decreased from 395 $CH_4$ $10^3$ Mg in 1990 to 297 $CH_4$ $10^3$ Mg in 2008. $CH_4$ emissions converted into $CO_2$ equivalent were 8,303 $CO_2$-eq. $10^3$ Mg in 1990 and 6,229 $CO_2$-eq. $10^3$ Mg in 2008. Greenhouse gas emissions from paddy field in Korea showed that it was gradually going down as the cultivation area decreased. In 4F: Field Burning, methane emissions by burning crop residue increased from 2,502 $CH_4$ Mg in 1990 to 2,726 $CH_4$ Mg in 2008. Emissions converted $CH_4$ into $CO_2$ equivalent were 53 $CO_2$-eq. $10^3$ Mg in 1990 and 57 $CO_2$-eq. $10^3$ Mg in 2008. Total emissions of $CH_4$ from the cropland sector declined from 8,356 $CO_2$-eq. $10^3$ Mg in 1990 to 6,287 $CO_2$-eq. $10^3$ Mg in 2008.

• Korean Journal of Environmental Agriculture
• /
• v.37 no.3
• /
• pp.213-220
• /
• 2018

BACKGROUND: This study was carried out to determine characteristics of residual pesticides in time-dependent manner and calculate half-lives of the residual pesticides in fresh and dried Chinese matrimony vine. In addition, processing factors were calculated based on the residual concentrations in them. METHODS AND RESULTS: The test pesticides, etofenprox and fenitrothion, were sprayed onto the Chinese matrimony vine plants at once or twice (at seven-day interval) and then samples were collected at 0 (after 3 hours), 1, 3, 5 and 7 days after the last spraying. Dried samples were prepared in hot-air drying oven at $60^{\circ}C$ for 48 hours until water content of less than 20%. Residual concentrations of etofenprox in fresh and dried samples decreased by 54.0-60.9% after 7 days of the last pesticide-application. In case of fenitrothion, the concentrations were found to have decreased by 69.2-76.5%. Processing factors of etofenprox were 2.6-3.0 for the one-time spraying and 2.5-3.0 for the two-time spraying and those of fenitrothion were found to be 1.5-22 for the one-time spraying and 1.6-2.0 for the two-time spraying. First half-lives of etofenprox and fenitrothion in fresh and dried samples ranged from 5.0 to 6.3 and from 3.4 to 4.0 days, respectively. The third half-lives were found to be 15.0-18.9 and 10.2-12.1 days, respectively. CONCLUSION: Residual concentrations of the tested pesticides in the studied crop decreased, but those in the dried samples appeared to have increased. In addition, processing factor and half life were constant regardless of spraying times.