Current Issue 2021. Vol.40, Iss.2

Orginal Articles

• Establishment of Heading-back Pruning Severities of Trunk at Planting in the One-year-old 'Daeneung' Jujube Whip Nursery Tree

  Lee-Hyuk Cho, Dong-Hoon Sagong / Korean Journal of Environmental Agriculture / 2021 / v.40, no.2, 73-82

  https://doi.org/10.5338/KJEA.2021.40.2.9

  Abstract Full-Text PDF

  Abstract

  

  BACKGROUND:

  The successful management of jujube trees depends on maintaining a balance between reproductive and vegetative growth. In general, heading cuts of trunk stimulate rather vegetative growth, but could decrease flower initiation. This study was conducted to establish a heading-back pruning severities at planting in the one year old ‘Daeneung’ jujube whip nursery tree by investigating vegetative growth and fruit yield.

  METHODS AND RESULTS:

  The heading back pruning severity was assigned as 5 different ranges as follow: one bud (TR-10, heading back pruning was 10 cm above the ground), three buds (TR-30), five buds (TR-50), seven buds (TR-70), and nine buds (TR-90) were left of scion. The number of buds on whip trunk was correlated to the central leader length and increment of trunk cross-sectional area, negatively, and to the tree height and canopy volume, positively. The yields in the TR-50 treatment were higher about 2 times than other treatments. The fruit diameter was not significantly different among the treatments.

  CONCLUSION:

  These results indicated that the optimum location of heading-back pruning in one year old ‘Daeneung’ jujube tree was 50 cm above the ground as evaluated by the balance of reproductive and vegetative growth.

• Improvement of Salt Accumulated Soil and Crop Growth using Coal Ash

  Jong Cheol Lee, Se Jin Oh, Min Woo Kang, Young Hyun Kim, Dong Jin Kim, Sang Soo Lee / Korean Journal of Environmental Agriculture / 2021 / v.40, no.2, 83-91

  https://doi.org/10.5338/KJEA.2021.40.2.10

  Abstract Full-Text PDF

  Abstract

  

  BACKGROUND:

  Cultivation area using agricultural plastic film facilities in Korea is rapidly increasing every year; however, it accelerates the salt accumulation in soils due to repeated cultivation and excessive use of chemical fertilizers. Coal ash contains various trace elements and has high potential to be used in agricultural purposes. This research was aimed to improve the quality of salts-accumulated soils and crop growth grown in the plastic film facilities using the soil amendment derived from coal ash and zero-valent iron powder.

  METHODS AND RESULTS:

  Soil amendment used in the study was manufactured using coal ash with iron powder and subjected to a typical upland soil for soil quality enhancement and two salts-accumulated soils for crop growth. After one month incubation of the salts-accumulated soils treated with the soil amendment, soil pH increased significantly and soil EC decreased by approximately 50%, compared to the control or the treatment without the soil amendment. Since the soil salts’ concentration is proportional to EC, the subjected soil amendment can be proposed as an effective way to overcome soil salts accumulation in agricultural plastic film facilities. For crop growth, the length of roots and stems increased by approximately 10% and the dry weight also increased by a maximum of 75%, compared to the control.

  CONCLUSION:

  The soil amendment made from waste resources such as coal ash and zero-valent iron was found to not only be effective in improving salt-accumulated soils and crop yield but also be safe against harmful heavy metals.

• Uptake and Translocation of Ethoprophos Mixed with Soil for Cultivation of Preceding Crop into Succeeding Crop

  Se-Yeon Kwak, Sang-Hyeob Lee, Hyo-Young Kim, Byung-Gon Shin, Jang-Eok Kim / Korean Journal of Environmental Agriculture / 2021 / v.40, no.2, 92-98

  https://doi.org/10.5338/KJEA.2021.40.2.11

  Abstract Full-Text PDF

  Abstract

  

  BACKGROUND:

  Unintentional residual pesticide in soil derived from preceding crops and the transfer to succeeding crops was considered a critical barrier for positive list system (PLS). Thus, an uncertain risk is predicted for ethoprophos applied at cultivation of preceding crop (Korean cabbage) to succeeding crop (spinach).

  METHODS AND RESULTS:

  Ethoprophos was treated on soil following the recommended dose and 5 times dose according to the safe use guidelines for Korean cabbage after seeding. On the 4 days after harvesting of preceding crop, spinach was sowed. The initial residual amounts of ethoprophos on soil (7.081-19.493 mg/kg) were decreased to 3.832-7.218 mg/kg until the harvest of Korean cabbage, and then finally decreased to 0.011-0.079 mg/kg after spinach cultivation. The uptake rates of ethoprophos from soil by Korean cabbage were 0.01-0.03% and distributed to root (0.150-0.903 mg/kg) and shoot (0.021-0.151 mg/kg), respectively. The residual amounts of uptake and translocation from preceding crop cultivated soil to spinach edible part were found to be below LOQ.

  CONCLUSION:

  The plant back internal (PBI) for ethoprophos is not recommended during sequential cultivation of leafy vegetables, since the residual amounts of ethoprophos in spinach were less than MRL (0.02 mg/kg).

• Plant Back Interval of Fluopyram Based on Primary Crop-derived Soil and Bare Soil Residues for Rotational Cultivation of Radish

  Young Eun Kim, Ji Hyun Yoon, Da Jung Lim, Seon Wook Kim, Hyunjeong Cho, Byeung Gon Shin, Hyo Young Kim, In Seon Kim / Korean Journal of Environmental Agriculture / 2021 / v.40, no.2, 99-107

  https://doi.org/10.5338/KJEA.2021.40.2.12

  Abstract Full-Text PDF

  Abstract

  

  BACKGROUND:

  Pesticide uptake by a rotational crop after being used for the primary crop is a potential cause of violation against the pesticide law if the pesticide is not registered in the secondary crop. This study was conducted to investigate the plant back interval (PBI) of fluopyram for the rotational cultivation of radish.

  METHODS AND RESULTS:

  Two experimental approaches were performed the evaluation of residues in radish cultivated successively in soil 16 days after treated with fluopyram onto pepper plant (T1) and in radish cultivated in bare soil treated with fluopyram at PBI 30 and PBI 60 days (T2). A modified QuEChERS method coupled with LC/MS/MS analysis showed good linearity of matrix-matched standard calibration of fluopyram with the coefficient values of determination greater than 0.995. Recovery values at levels of 0.01, 0.05, 0.1 and 0.25 mg/kg ranged from average 84.9 to 117.6% with RSD less than 10%. Fluopyram residues in radish harvested from T1 and T2 were found as levels less than maximum residue limit.

  CONCLUSION:

  This study suggests 20~30 days as the PBI of fluopyram for the rotational cultivation of radish in the greenhouse soil treated with fluopyram used for pepper as the primary crop.

• Determination and Validation of an Analytical Method for Dichlobentiazox in Agricultural Products with LC-MS/MS

  Sun Young Gu, Han Sol Lee, Ji-Su Park, Su Jung Lee, Hye-Sun Shin, Sung Eun Kang, Yun Mi Chung, Ha Na Choi, Sang Soon Yoon, Young-Hyun Jung, Hae Jung Yoon / Korean Journal of Environmental Agriculture / 2021 / v.40, no.2, 108-117

  https://doi.org/10.5338/KJEA.2021.40.2.13

  Abstract Full-Text PDF

  Abstract

  

  BACKGROUND:

  Dichlobentiazox is a newly registered pesticide in Korea as a triazole fungicide and requires establishment of an official analysis method for the safety management. Therefore, the aim of this study was to determine the residual analysis method of dichlobentiazox for the five representative agricultural products.

  METHODS AND RESULTS:

  Three QuEChERS methods were applied to establish the extraction method, and the EN method was finally selected through the recovery test. In addition, various adsorbent agents were applied to establish the clean-up method. As a result, it was found that the recovery of the tested pesticide was reduced when using the d-SPE method with PSA and GCB, but C₁₈ showed an excellent recovery. Therefore this method was established as the final analysis method. For the analysis, LC-MS/MS was used with consideration of the selectivity and sensitivity of the target pesticide and was operated in MRM mode. The results of the recovery test using the established analysis method and inter laboratory validation showed a valid range of 70-120%, with standard deviation and coefficient of variation of less than 3.0% and 11.6%, respectively.

  CONCLUSION:

  Dichlobentiazox could be analyzed with a modified QuEChERS method, and the method determined would be widely available to ensure the safety of residual pesticides in Korea.

• Monitoring and Risk Assessment of Pesticide Residues in Pre-harvest Fresh Ginseng (Panax ginseng C. A. Meyer) in Chungbuk Province in 2019

  Tae Hwa Song, Young Wook Lee, Taek Han Youn, Eun A Park, Eun Sun Shim, Ju Hee Lee, Kee Sung Kyung / Korean Journal of Environmental Agriculture / 2021 / v.40, no.2, 118-126

  https://doi.org/10.5338/KJEA.2021.40.2.14

  Abstract Full-Text PDF

  Abstract

  

  BACKGROUND:

  It is very important to monitor the residual characteristics of pesticides in pre-harvest fresh ginseng to ensure consumer safety.

  METHODS AND RESULTS:

  Forty-eight fresh ginseng samples were collected from 8 ginseng-growing fields 10 days before harvest and pesticide residues in fresh ginseng with and without rhizome (head of ginseng) and rhizome were analyzed for 320 pesticides by using GC-MS/MS and LC-MS/MS. As a result of the pesticide residue analysis, the number of pesticides detected from the fresh ginseng with rhizome, that without rhizome and rhizome were 26, 25, and 40, respectively, indicating that high number of pesticides found in rhizome, compared with the other parts. Pyraclostrobin was detected with the highest frequency in all samples, reaching to 21.2% in fresh ginseng with rhizome, 16.8% in that without rhizome, and 14.8% in rhizome.

  CONCLUSION:

  The residue levels of pesticides detected did not exceed their maximum residue limits, in spite of residual data in fresh ginseng before harvest. The amounts of the estimated daily intakes of all the detected pesticides were found to be from 0.018 to 1.818% of their acceptable daily intakes, indicating that concentrations of pesticides detected from fresh ginseng with and without rhizome collected before harvest do not pose the immediate health risks.

• Development and Validation of Dithiocarbamates Fungicide Analytical Method using CS₂ Trap Method in Livestock Product

  Hyeong-Wook Jo, Jung-Hun Sun, Hyo-Min Heo, Sang-Hyeob Lee, Jang-Eok Kim, Joon-Kwan Moon / Korean Journal of Environmental Agriculture / 2021 / v.40, no.2, 127-133

  https://doi.org/10.5338/KJEA.2021.40.2.15

  Abstract Full-Text PDF

  Abstract

  

  BACKGROUND:

  Dithiocarbamte fungicides have been used in crop cultivation for diseases protection and treatment. And cultivated agricultrual products were used as feedstuff, and residual pesticides are likely to be absorbed and transferred to livestock. But the maximum residue limits (MRLs) were not established for dithiocarbate fungicides in livestock products, and thus an analysis method was developed and validated for dithiocarbamate fungicides to establish MRLs.

  METHODS AND RESULTS:

  Samples were prepared using CS₂ trap method and detected with UV/VIS spectrophotometer. Calibration line (0.1 ∼ 10 ㎍/mL) was linear with r² ⟩ 0.99. For validation, the recovery tests were carried out at three fortification levels (MLOQ, 10 MLOQ and 50 MLOQ) from livestock samples (egg, milk, beef, pork, and chicken). The results for mancozeb, propineb, and thiram ranged between 76.8 to 109.6%, 79.4 to 108.8%, and 80.2 to 107.8%, respectively and % RSD (relative standard deviation) values were below 9.5%. Furthermore, inter-laboratory analysis was performed to validate the method.

  CONCLUSION:

  All values were corresponded with the criteria ranges requested by both the CODEX (CAC/GL 40-1993, 2003) and MFDS guidelines (2016). This might be used as an official analytical method for determination of dithiocarbamate fungicides at established MRLs and monitoring.

• Development of Analytical methods for Chinomethionat in Livestock Products

  Seung-Hyun Yang, Jeong-Han Kim, Hoon Choi / Korean Journal of Environmental Agriculture / 2021 / v.40, no.2, 134-141

  https://doi.org/10.5338/KJEA.2021.40.2.16

  Abstract Full-Text PDF

  Abstract

  

  BACKGROUND:

  The analytical method was established for determination of fungicide chinomethionat in several animal commodities using gas chromatography (GC) coupled with electron capture detector (ECD).

  METHODS AND RESULTS:

  In order to verify the applicability, the method was optimized for determining chinomethonat in various livestock products including beef, pork, chicken, milk and egg. Chinomethionat residual was extracted using acetone/dichloromethane(9/1, v/v) with magnesium sulfate and sodium chloride (salting outassociated liquid-liquid extraction). The extract was diluted by direct partitioning into dichloromethane to remove polar co-extractives in the aqueous phase. The extract was finally purified with optimized silica gel 10 g.

  CONCLUSION:

  The method limit of quantitation (MLOQ) was 0.02 mg/kg, which was in accordance with the maximum residue level (MRL) of chinomathionate as 0.05 mg/kg in livestock product. Recovery tests were carried out at two levels of concentration (MLOQ, 10 MLOQ) and resulted in good recoveries (84.8~103.0%). Reproducibilities were obtained (Coefficient of variation <5.2%), and the linearity of calibration curves were reasonable (r²>0.995) in the range of 0.01-0.2 μg/mL. This established analytical method was fully validated and could be useful for quantification of chinomathionat in animal commodities as official analytical method.

• Development of Simultaneous Analytical Method for Thiodicarb and its Metabolite Methomyl in Livestock Products

  Hee-Ra Chang, Jung-Sun You, Sun-Woo Ban, Hye-min Gwak / Korean Journal of Environmental Agriculture / 2021 / v.40, no.2, 142-147

  https://doi.org/10.5338/KJEA.2021.40.2.17

  Abstract Full-Text PDF

  Abstract

  

  BACKGROUND:

  Agricultural use and pest control purposes of pesticides may lead to livestock products contamination. Thiodicarb and its degraded product, methomyl, are carbamate insecticides that protect soya bean, maize, fruit, and vegetables and control flies in animal and poultry farms. For maximum residue limit enforcement and monitoring, the JMPR residue definition of thiodicarb in animal products is the sum of thiodicarb and methomyl, expressed as methomyl. This residue definition was set to consider the fact that thiodicarb was readily degraded to methomyl in animal commodities. And therefore the simultaneous analytical method of thiodicarb and methomyl is required for monitoring in livestock products.

  METHODS AND RESULTS:

  The study was conducted using a quick, easy, cheap, effective, rugged, and safe (QuEChERS) method and HPLC-MS/MS to determine the thiodicarb and methomyl in livestock products. The limit of quantitation (LOQ) was 0.01 mg/kg for livestock products, including beef, pork, chicken, milk, and egg. The coefficient of determinations (r²) for the calibration curve were > 0.99, which was acceptable values for linearity. Average recoveries at spiked levels (LOQ, 10LOQ, and 50LOQ, n=5) in triplicate ranged from 73.2% to 102.1% and relative standard deviations (RSDs) were less than 10% in all matrices.

  CONCLUSION:

  The analytical method was validated for the performance parameters (specificity, linearity, accuracy, and precision) in livestock products to be acceptable by the CODEX guidelines.