Kwang-Yong Ko

Residual Pattern of Procymidone and Chlorothalonil in Grape During the Period of Cultivation and Storage

In order to know the residual pattern of pesticides and predict to the degradation period until below MRL we experimented procymidone and chlorothalonil for grape which were the most detected pesticide in grape by NAQS(National Agricultural product Quality management Service) survey. In this experiment we sprayed those pesticides 10 days before harvest and analyzed 0, 1, 2, 3, 5, 7, 10 day sample to establish logical equation and to calculate . Also the same day samples stored at and , which were compared their degradation patterns. During the cultivating period, the residue amount of procymidone was changed from 1.85 mg/kg (0 day) to 0.33 mg/kg (10 day), was 3.5 days, and chlorothalonil was changed from 5.5 mg/kg (0 day) to 3.49 mg/kg (10 day), was 4.4 days. During the storage period, of procymidone and chlorothalonil at were 10.5 and 7.6 days, and 6.3 and 6.1 days at , respectively.

Residue Patterns of Procymidone, Chlorpyrifos and Cypermethrin in Peaches During Cultivation and Storage Period

The residue patterns of procymidone, chlorpyrifos and cypermethrin in peaches were examined. The pesticides were sprayed at 15 days before harvest and then were determined the residue at 0, 1, 2, 3, 5, 7, 10 and 15 days after pesticide application and calculated their . Also, the degradation patterns at and during storage period were compared. Biological half-lives of procymidone, chlorpyrifos and cypermethrin in peaches during the cultivation period were 3.1, 7.2 and 10.4 days, respectively. The biological half -life of procymidone was shorter than the others. During the storage period, half-lives of procymidone, chlorpyrifos and cypermethrin were 16.0, 14.3 and 13.1 days at and 4.6, 10.2 and 12.9 days at , respectively. The degradation rates of these three pesticides in storage period were slower than them in cultivation period. Removal rates were by tap water, and by detergent solution.

Effect of Amino Acid Fertilization on Nitrate Assimilation of Leafy Radish and Soil Chemical Properties in High Nitrate Soil

Abstract The objective of the present work was to investigate the corresponding uptake and assimilation of nitrate (NO3 −) in leafy radish and effects on soil chemical properties by foliar application of amino acid fertilizer (AAF). The activity of the enzymes related to the process of NO3 − reduction (NR: nitrate reductase; NiR: nitrite reductase; GS: glutamine synthetase) and the content of NO3 −, total N, and the end products of this process (amino acids and proteins) were analyzed. The soils were sampled twice, and some chemical properties were analyzed. The results of this study showed that application of AAF increased biomass production, and nitrogen (N) utilization in the treatment of a low rate of AAF increased 55% over the control. In addition, the activities of the enzymes were affected differently depending on applied rate of AAF. Furthermore, the NO3 − content was reduced 4–24%, and total N content was increased 14–32% by AAF treatments. Finally, application of AAF improved uptake efficiency of N from soil and prevented N loss by leaching.

Residual Pattern of Procymidone and Bifenthrin in Perilla Leaf During the Period of Cultivation and Storage

In order to know residual pattern of pesticides and to predict degradation period until below MRL, we experimented with procymidone and bifenthrin for perilla leaf which were the most detected pesticides by NAQS (National Agriculture-product Quality management Service) survey. In this experiment, we sprayed those pesticides 10 days before harvest and analyzed 0, 1, 2, 3, 5, 7, 10 day samples to establish logical equation and to calculate . Also degradation patterns of those samples were compared during storage at 4t and 20t. During cultivating period, procymidone residue amount was changed from 79.52 mg/kg (0 day) to 4.2 mg/kg, was 2.65 days by logical-equation, and bifenthrin residue amount was changed from 5.03 mg/kg (0 day) to 0.17 mg/kg, was 2.24 days. During storage period, of procymidone and bifenthrin at was 12.23 days and 10.57 days, and at was 6.32 days and 8.2 days, respectively.

Enhancement of nitrate uptake and reduction by treatment with mixed amino acids in red pepper (Capsicum annuum L.)

Abstract The objective of the present work was to determine the corresponding uptake and assimilation of in roots and leaves by the application of mixed amino acids in red pepper. The amino acids used in this experiment were alanine, β-alanine, aspartic acid, asparagines, glutamic acid, glutamine, and glycine. The 42-day-old seedlings were treated with 0, 0.3, and 3.0 mM of mixed amino acids containing 10 mM in growth medium. Nitrate uptake was determined by following depletion from the uptake solution. The activity of the enzymes related to the process of reduction and the content of , , and the end-products of this process (amino acids and proteins) were analyzsed in leaves and roots. The results of this study indicate that the application of mixed amino acids increased uptake in red pepper, and the highest uptake was found in the treatment with 3.0 mM mixed amino acids that was nearly seven times higher than the control. In addition, the enzymatic activities of nitrate reductase and nitrite reductase were positively affected by the treatments of mixed amino acids in the roots. The results presented here are in contrast to recent studies, which have shown that the single amino acid treatments inhibited uptake and nitrate reductase activity. Finally, the content was decreased both in leaves and roots by the mixed amino acids treatments.

Risk Assessment for Heavy Metals in Soil, Ground Water, Rice Grain nearby Abandoned Mine Areas

Received: 12 March 2013 / Revised: 16 May 2013 / Accepted: 1 July 2013 c 2013 The Korean Society of Environmental Agriculture This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Dissipation and Removal Rate of Dichlofluanid and Iprodione Residues on Greenhouse Cherry Tomato

We studied the residual patterns of two fungicides, dichlofluanid and iprodione, in cherry tomato greenhouse after applying with the recommended and double dose. Also, the degradation patterns during storage periods of up to ten days were compared between at room temperature (20) and at cold temperature (4). Removal rates of fungicides by washing with tap-water and detergent solution (0.1%, 0.2%) were measured. Half-lives of dichlofluanid and iprodione in greenhouse cherrytomato were 2.23.5 and 3.35.4 days, respectively. During the storage period, the residues were dissipated more slow. Removal rates were 62.880.3% by tap-water, 60.483.1% by 0.1% detergent solution, and 65.377.6% by 0.2% detergent solution. So, we can predict of terminal residues from cultivation period to marketing, storage and consuming.

Determination of Abamectin Residue in Paprika by High-Performance Liquid Chromatography

Reversed-phase high-performance liquid chromatography (HPLC) techniques were developed to quantify abamectin (ABM) in paprika ( Capsicum annum ). Separation was achieved on a C 18 ODS column with a mobile phase of acetonitrile/water (96/4 v/v) mixture in an isocratic elution at the flow rate of 1.2 , ,, , mL/min for avermectins (AVMs). The retention times were 8.0 and 9.7mins for AVM B 1b and AVM B 1a , respectively. Residual AVMs (sum of AVM B 1a , AVM B 1b and 8,9-Z-AVM B 1a ) in the vegetable were ext- racted with acetonitrile, and the silica solid-phase extraction cartridges were used to purify the extracts. AVMs were derivatized using trifluoroacetic acid and 1-methylimidazole, and the derivatives were determined with a fluorescence detector (excitation at 365 nm and emission at 470 nm). High and consistent recoveries, ranging from 93% to 115%, were obtained for AVM B 1a and 8, 9-Z-AVM B 1a at fortified levels of 20 g/kg and μμ μ 200 g/kg for paprika. The limit of quantitation (LOQ) was 2 g/kg. The residual levels of AVMs in pap μ μ μ μ μ μ μ μ - rika in a field experiment from one day to seven days after the last application decreased from 18.40 to 7.59 g/kg. The half-life (T μμ μ 1/2 ) of AVMs in paprika was 1.47 days.

Low Molecular Weight Organic Acids in Brassica pekinensis Rupr. and Growing soil Influenced by Simulated Nitrate Deposition

We investigated whether carboxylate exudation of Brassica pekinensis Rupr. was affected by nitrate deposition from simulated acid rain. A gas chromatographic (GC) analysis was employed for the determination of low molecular weight organic acids (LOA) in rhizosphere soils, bulk soil, roots and leaves of Brassica pekinensis Rupr.. Rhizosphere soils were collected after 8 weeks of plant growth by first removing the bulk soil from the root system and then by mechanical move off the rhizosphere soil that adhered to the root surface with soft brush. Soil and plant materials were simultaneously extracted with the mixture of methanol and sulfuric acid (100:7, v/v). Seven organic acids, oxalic, malonic, fumaric, succinic, maleic, L-malic and citric acid were identified and quantified by GC equipped with FID. Oxalic, L-malic, and citric acids were found in both the bulk and rhizosphere soils, while most LOAs were not detected in the control treatment. On the contrary, except maleic acid, all other organic acids were detected in the leaves and roots of cabbages treated with nitrate deposition.