p-ISSN 1225-3537e-ISSN 2233-4173
Eun Shik Na,
Yong Jae Lee,
Seong Soo Kim,
Hyun Seok Seo,
June Sang Ryu,
Seung Hyeon Jo,
Hyun Ho Noh,
Dan Bi Kim
/ Korean Journal of Environmental Agriculture / 2020 / v.39, no.2, 83-88
This study was carried out to investigate residual characteristics of diethofencarb during ginseng cultivation and processing, and to establish the maximum residue limits (MRL) of ginseng and its processed products.
Supervised field trials were conducted from three fields located at Seosan, Goesan and Jeongeup in Korea. Diethofencarb 25% WP was diluted by 500 times and sprayed 4 times onto the ginseng with 10 days interval. The samples were collected at 80 days after final application. The residual amounts of diethofencarb ranged from 0.074 to 0.460 mg/kg in fresh ginseng, from 0.292 to 0.720 mg/kg in dried ginseng, and from 0.208 to 0.557 mg/kg in red ginseng. These data exceeded the ginseng’s MRL, 0.3 mg/kg. The processing factors of diethofencarb in processed products were found to be 2.64 and 1.99, respectively for dried and red ginseng.
Given the lower residual concentration of red ginseng that goes through a more complicated process than dried ginseng, the residual concentrations of diethofencarb in processed ginseng products were found to be dependent on processing method. Therefore, it is necessary to reconsider the MRL of diethofencarb in fresh ginseng and its processed products.
Eun Hea Jho
/ Korean Journal of Environmental Agriculture / 2020 / v.39, no.2, 89-94
Persistent organic contaminants such as dichlorodiphenyltrichloroethane (DDT) are often found in agricultural soils decades after it was banned in Korea. This study uses hemoglobin and hemoglobin-containing blood meal to reduce the residual DDT in soil.
Hemoglobin or blood meal with or without hydrogen peroxide (H2O2) was mixed with the DDT-spiked soil prepared for this study, and samples were taken over 14 d-degradation period to measure the residual DDT concentrations. With only hemoglobin, DDT was completely removed after 14 d, while with both hemoglobin and H2O2, 73%, on average, removal was observed. Similarly, the blood meal removed 73% of DDT, but with H2O2, the DDT removal was only 39%. The lower DDT removal in the presence of H2O2 can be attributed to the adverse effects of reactive species. Hemoglobin was more effective than blood meal for DDT removal in a given time; however, with additional blood meal injection, complete DDT removal was achieved
Overall, this study shows that the blood meal that is used as a fertilizer can potentially be used to remove residual contaminants such as DDT in agricultural soil.
/ Korean Journal of Environmental Agriculture / 2020 / v.39, no.2, 95-105
In this study, in order to verify the effects of supplemented organic amendment fertilizers recommended by the soil testing on cabbages, we used various amounts of organic amendment fertilizers. The amount of organic amendment fertilizers was decided by calculating each ratio of inorganic nitrogen, phosphorus, and potassium based on the recommended fertilizer composition.
The cabbages subjected to treatments 1 and 2 showed similar or greater leaf colors (SPAD values), head heights, head widths, head weight, soil organic matter content, nitrate-nitrogen level, and conductivity after harvest, when compared with cabbages treated with chemical fertilizers. The phosphorus and potassium fixation in the soil were higher in the plot where cabbages were treated with chemical fertilizers, and the nutrient use efficiency was greater in the plots with organic amendments and mineral addition.
The treatments 1 and 2 that were supplemented with 180-200% of nitrogen, 100-130% of phosphorus, and 185-250% of potassium in comparison to chemical fertilizers, applied by the inorganic ratios of nitrogen, phosphorus, and potassium can be used as organic amendment fertilizers for cabbages.
/ Korean Journal of Environmental Agriculture / 2020 / v.39, no.2, 106-113
Bumblebees have been shown to be very effective pollinators for most greenhouse tomatoes. Neonicotinoid insecticides are one of the most widely used pesticides in tomato crops in Korea.
This study was carried out to investigate the toxicity of four neonicotinoid insecticides (clothianidin, dinotefuran, imidacloprid and thiamethoxam) to bumblebees based on the OECD guidelines (No.246, 247). The 48 hr LD50 (μg a.i. /bumblebee) values in the acute contact toxicity tests were determined as follows: clothianidin, 0.467; dinotefuran, 3.741; imidacloprid, 3.967; and thiamethoxam, 0.747. The 48 hr LD50 values in the acute oral toxicity tests were determined as follows: clothianidin, 0.005; dinotefuran, 0.056; imidacloprid, 0.325; and thiamethoxam, 0.018. The acute contact and oral toxicity of the test insecticides to bumblebees from most to least toxic was clothianidin > thiamethoxam > dinotefuran > imidacloprid.
This study provided the basic toxicological data of neonicotinoid insecticides for bumblebees. In the near future, acute toxicity and mixture toxicity of other pesticides to bumblebees could be determined using this method.
/ Korean Journal of Environmental Agriculture / 2020 / v.39, no.2, 114-121
Biochar-based fertilizers delay the nutrient release and feature a slow release effect for agricultural and environmental advantages. This experiment was conducted to evaluate agro-environmental effects of different application ratios of modified biochar pellets supplemented.
The treatments consisted of the control, 40% N, 60% N and 60% N (0.07M MgO) of modified supplemented biochar pellets (MSBP), which were based on recommended ratio of nitrogen for rice cultivation. For the paddy water, the NH4-N and NO3-N concentrations in whole treatments rapidly increased at 84 days and 40 days after transplanting, respectively. The PO4-P concentrations in the MSBP were generally lower than those of the control. For the paddy soil, NH4-N concentrations in the MSBP were higher than those of the control at 5 days after transplanting, while NO3-N concentrations were not significantly different in the treatments through rice cultivation. P2O5 concentrations in the control were higher than those of the MSBP until 40 days after transplanting while K2O concentrations were not significantly different among the treatment. The highest carbon sequestration was 970 kg ha-1 in the 60% N (0.07M MgO), and the potential carbon storage in the 60% N (0.07M MgO) was higher at 222 kg ha-1 than the control during rice cultivation. It shown that the rice yield in the control was not significantly different from the 40% N and 60% N (0.07M MgO) application plots.
Application of MSBP for rice cultivation was effective for carbon sequestration and agro-environmental effects even though nitrogen application ratio was reduced at 40% based on recommended application ratio of fertilizer.
/ Korean Journal of Environmental Agriculture / 2020 / v.39, no.2, 122-129
Dissipation patterns of insecticides (acequinocyl, clothianidin, diflubenzuron, thiacloprid, and thiamethoxam) on strawberry grown in plastic-covered greenhouse were evaluated at 7 intervals including the preharvest interval after application. This study was performed to determine the residue concentrations, half-lives and dissipation rates in strawberry for the harvest periods.
Acequinocyl, clothianidin, diflubenzuron, thiacloprid, and thiamethoxam were applied in accordance with critical good agricultural practices for strawberry. Strawberry samples were collected at 0, 1, 2, 3, 5, 7 and 10 days after application. Quantitaion was performed by HPLC/DAD and HPLC-MSMS system with C18 column. The limit of quantitation (LOQ) values varied between were 0.00025~0.05 mg/kg on strawberry. The recoveries of acequinocyl, clothianidin, diflubenzuron, thiacloprid and thiamethoxam at two concentrations ranged from 70.9~104.9% on strawberry. The half-lives of pesticide dissipation on strawberry for two fields ranged from 1.3~8.2 days. The dissipation rates were evaluated according to the statistics method with a 95% confidence.
The residue levels of insecticides (acequinocyl, clothianidin, diflubenzuron, thiacloprid, and thiamethoxam) on strawberry at 0-day after application were below the specified values by Korean MRL. To estimate dissipation rate constant of pesticides on crop for harvest periods, it is important to set the pre-harvest residue limit for human health and consumer protection in Korea.
Han Sol Lee,
Su Jung Lee,
Sang Soon Yun,
/ Korean Journal of Environmental Agriculture / 2020 / v.39, no.2, 130-137
Mefentrifluconazole and triticonazole are the triazole fungicides. The maximum residue levels for agricultural products need to be set up. Therefore, development of the official analytical method for determination of mefentrifluconazole and triticonazole residues from agricultural crops was necessary due to safety management, and then a simultaneous analytical method was developed for the determination of mefentrifluconazole and triticonazole in agricultural crops.
Samples were extracted using acetonitrile and purified using dispersive solid phase extraction, and then detected with liquid chromatograph-tandem mass spectrometry (LC-MS/MS). Matrix-matched calibration curves (0.0025-0.25 μg/mL) were linear into a sample extract with r2>0.99. For validation, the recovery test was carried out at three fortification levels (LOQ, 10 LOQ and 50 LOQ) from agricultural samples. The results for mefentrifluconazole and triticonazole ranged between 92.3 to 115.3% and 91.4 to 108.5%, respectively and RSD (relative standard deviation) values were also below 6.0%. Furthermore, inter-laboratory was conducted to validate the method.
All values were corresponded with the criteria ranges requested by both the CODEX (CAC/GL 40-1993, 2003) and MFDS guidelines (2016). Therefore, the proposed method can be used as an official analytical method for determination of mefentrifluconazole and triticonazole (triazole fungicides) in the Republic of Korea.
Mi Kyung Lee,
Sung Yung Yoo,
Tae Wan Kim,
/ Korean Journal of Environmental Agriculture / 2020 / v.39, no.2, 138-141
Fresh weight is one of the major quality measurement factors in determining the quality of fresh fruits. A practical method has been developed for rapid and non-destructive measurement using the Chlorophyll Fluorescence Image (CFI) technique to estimate changes in fresh weight of post-harvest products.
Kiwifruit (Actinidia deliciosa) was used and measured for the fresh weight and CFI under different temperature conditions at 0, 10, and 20℃, from 0 to 21 days after storage (DAS). We observed the fresh weight of kiwifruit and measured the surface image for determining Fv/Fm value in terms of maximum quantum yield on each day. To estimate freshness of kiwifruit we applied linear regression between the measured fruit weights and Fv/Fm values. Results showed that fruit weights were reduced by 4% at 0℃, 6% at 10℃, and 14% at 20℃ for 21 days, respectively. And also, the value of Fv/Fm was shown as decreasing trend at all temperature conditions, especially at 20 ℃. Fv/Fm values showed highly significant correlation (R2>0.9) with fresh weight of kiwifruit at all different storage temperatures.
Thus, CFI technique can be useful to estimate the fresh weight of kiwifruit.
Eun Shik Na,
Seong Soo Kim,
Sung Soo Hong,
Kyoung Ju Kim,
Yong Jae Lee,
Byung Chul Lee,
Kyu Seung Lee
/ Korean Journal of Environmental Agriculture / 2020 / v.39, no.2, 142-169
A new analytical method has been developed to determine 261 pesticide residues in herbal medicines.
The extraction of pesticides was carried out by modified method of the Korea Food Standards Codex sample extraction and determination was performed using GC-MS/MS and LC-MS/MS. During the pre-treatment process of the test method, Solid-liquid separation was changed to centrifugation. The method was validated by the precision and accuracy results. 261 pesticides spiked at three level 20, 50, 100 ug/kg in herbal medicines. The limit of quantification of method were 4-40 ug/kg for GC-MS/MS and 2-45 ug/kg for LC-MS/MS, respectively. Among the pesticides analysed by GC-MS/MS and LC-MS/MS, 244 pesticides (94% of total number) in chinese matrimony vine and 224 pesticides (86% of total number) in korean angelica root and 231 pesticides (89% of total number) in jujube and 214 (82% of total number) in cnidium showed recoveries in the range of 70-120% with RSD≤20%.
These results indicated that GC-MS/MS and LC-MS/MS analysis with the sample extraction in this study can be applied to multi-residue analysis of pesticides in herbal medicines.