• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.296-313
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• 2014

A QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) multiresidue method was developed for the simultaneous analysis of 124 pesticides in soil by LC-MS. The procedure involved liquid extraction of soil immersed with 0.2N $NH_4Cl$ by acetonitrile with 1% acetic acid, followed by anhydrous $MgSO_4$ and sodium acetate, and dispersive SPE cleanup with $MgSO_4$, primary secondary amine (PSA) and $C_{18}$. The extracts were analyzed with LC-MS/MS in ESI positive mode. Standard calibration curves were made by matrix matched standards and their correlation coefficients were higher than 0.99. Recovery studies for the validation were carried out using two type soils, loam and sandy loam, at four concentration levels (0.005, 0.01, 0.02, and 0.1 mg/kg). The recoveries of pesticides were in the range of 70-120% with < 20% RSD except 4 pesticides, Benfuracarb, Ethiofencarb, Pymetrozine, and Pyrethrin. This result indicated that the method using QuEChERS and LC-MS/MS could be applied for the simultaneous determination of pesticide residues in soils.

• KSBB Journal
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• v.27 no.2
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• pp.75-85
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• 2012

Although, microbial arsenic mobilization by dissimilatory arsenate-reducing bacteria (DARB) and the practical use to the removal technology of arsenic from contaminated soil are expected, most previous research mainly has been focused on the geochemical circulation of arsenic. Therefore, in this review we summarized the previously reported DARB to grasp the characteristic for bioremediation of arsenic. Evidence of microbial growth on arsenate is presented based on isolate analyses, after which a summary of the physiology of the following arsenate-respiring bacteria is provided: Chrysiogenes arsenatis strain BAL-$1^T$, Sulfurospirillum barnesii, Desulfotomaculum strain Ben-RB, Desulfotomaculum auripigmentum strains OREX-4, GFAJ-1, Bacillus sp., Desulfitobacterium hafniense DCB-$2^T$, strain SES-3, Citrobacter sp. (TSA-1 and NC-1), Sulfurospirillum arsenophilum sp. nov., Shewanella sp., Chrysiogenes arsenatis BAL-$1^T$, Deferribacter desulfuricans. Among the DARB, Citrobacter sp. NC-1 is superior to other dissimilatory arsenate-reducing bacteria with respect to arsenate reduction, particularly at high concentrations as high as 60 mM. A gram-negative anaerobic bacterium, Citrobacter sp. NC-1, which was isolated from arsenic contaminated soil, can grow on glucose as an electron donor and arsenate as an electron acceptor. Strain NC-1 rapidly reduced arsenate at 5 mM to arsenite with concomitant cell growth, indicating that arsenate can act as the terminal electron acceptor for anaerobic respiration (dissimilatory arsenate reduction). To characterize the reductase systems in strain NC-1, arsenate and nitrate reduction activities were investigated with washed-cell suspensions and crude cell extracts from cells grown on arsenate or nitrate. These reductase activities were induced individually by the two electron acceptors. Tungstate, which is a typical inhibitory antagonist of molybdenum containing dissimilatory reductases, strongly inhibited the reduction of arsenate and nitrate in anaerobic growth cultures. These results suggest that strain NC-1 catalyzes the reduction of arsenate and nitrate by distinct terminal reductases containing a molybdenum cofactor. This may be advantageous during bioremediation processes where both contaminants are present. Moreover, a brief explanation of arsenic extraction from a model soil artificially contaminated with As (V) using a novel DARB (Citrobacter sp. NC-1) is given in this article. We conclude with a discussion of the importance of microbial arsenate reduction in the environment. The successful application and use of DARB should facilitate the effective bioremediation of arsenic contaminated sites.

• Journal of Korean Society on Water Environment
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• v.24 no.4
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• pp.488-498
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• 2008

Soil and Water Assessment Tool (SWAT) model have been widely used in simulating hydrology and water quality analysis at watershed scale. The SWAT model extracts topographic feature using the Digital Elevation Model (DEM) for hydrology and pollutant generation and transportation within watershed. Use of various DEM cell size in the SWAT leads to different results in extracting topographic feature for each subwatershed. So, it is recommended that model users use very detailed spatial resolution DEM for accurate hydrology analysis and water quality simulation. However, use of high resolution DEM is sometimes difficult to obtain and not efficient because of computer processing capacity and model execution time. Thus, the SWAT Topographic Feature Extraction Error (STOPFEE) Fix module, which can extract topographic feature of high resolution DEM from low resolution and updates SWAT topographic feature automatically, was developed and evaluated in this study. The analysis of average slope vs. DEM cell size revealed that average slope of watershed increases with decrease in DEM cell size, finer resolution of DEM. This falsification of topographic feature with low resolution DEM affects soil erosion and sediment behaviors in the watershed. The annual average sediment for Soyanggang-dam watershed with DEM cell size of 20 m was compared with DEM cell size of 100 m. There was 83.8% difference in simulated sediment without STOPFEE module and 4.4% difference with STOPFEE module applied although the same model input data were used in SWAT run. For Imha-dam watershed, there was 43.4% differences without STOPFEE module and 0.3% difference with STOPFEE module. Thus, the STOPFEE topographic database for Soyanggang-dam watershed was applied for Chungju-dam watershed because its topographic features are similar to Soyanggang-dam watershed. Without the STOPFEE module, there was 98.7% difference in simulated sediment for Chungju-dam watershed for DEM cell size of both 20 m and 100 m. However there was 20.7% difference in simulated sediment with STOPFEE topographic database for Soyanggang-dam watershed. The application results of STOPFEE for three watersheds showed that the STOPFEE module developed in this study is an effective tool to extract topographic feature of high resolution DEM from low resolution DEM. With the STOPFEE module, low-capacity computer can be also used for accurate hydrology and sediment modeling for bigger size watershed with the SWAT. It is deemed that the STOPFEE module database needs to be extended for various watersheds in Korea for wide application and accurate SWAT runs with lower resolution DEM.

• Journal of Practical Agriculture & Fisheries Research
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• v.7 no.1
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• pp.64-73
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• 2005

This study was done to determine the regional adaptability of Dioscorea opposita in Korea. Suwon, Chunchon, Kangneung, Yonchon and Taean had soil pH of 6.62, 5.65, 5.9, 5.9 and 5.82, respectively, being at more unfavorable conditions than a standard soil condition for yam with pH 6.2. The amounts of organic matter in Suwon, Chunchon, Taean, and Yonchon were 1.96%, 4.51%, 3.76%, 1.89% and 1.12%, respectively, being at more favorable conditions than a standard organic matter in soil for yam with 2.0~3.0%. As the results from cultivating of large plantings in different regions, Suwon showed the largest the tuber dry weight of 135g. In comparison of general component between round yam and short yam in the area of Kangneung, protein of round yam(3.30%) was higher than that of short yam(1.40%). Dryness in round yam(36.5%) was lower than that of short yam(28.9%), indicating a higher dry weight ratio of round yam. In tuber extracts analysis, saponins content was respectively 23.7mg/g in round yam and 10.4mg/g in short yam.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.4
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• pp.450-454
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• 1988

This study was conducted to increase the quality of Astrragali radix and to decide the application amounts of N, P and K fertilizer for Astragalus membranaceus Bunge. The ferlilizers effect on the ash contents and extracts from the root and the dried root yield was studied. With increasing the application amount of nitrogen more than 5kg/10a, the acid insoluble ash content of root increased, but the ethyl alcohol and diethyl ether extracts decreased. No effect of phosphorus amount on the ash and extracts contents in root was observed. With increasing amount more than 7kg/10a, only the acid insoluble ash contents increased. The dried root yield increased with the application level until 5kg/10a of nitrogen, but the effects ot phosphorus and potassium application were not observed. Positive correlation was obtained significantly between the ash ($r=0.746^*$) and acid insoluble ash ($r=0.858^{**}$) contents and the potassium application amount, and the negative correlation was also obtained significantly between the extract contents and the nitrogen ($r=-0.778^*$ ; $C_2H_5OH$, $r=-0.848^{**}$ ; $(C_2H_5O)_2O$) and potassium ($r=-0.772^*$ ; $(C_2H_5O)_2O)$ application amounts. As the results in the first year from the seeding, it is recommended for quality of Astragali radix to apply 5, 7-14, 7kg/10a of N, $P_2O_5$ and $K_2O$, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.3
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• pp.203-213
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• 2017

This study investigated the changes in yields, antioxidant compounds, and antioxidant activities among 11 adzuki bean cultivars cultivated in a paddy field with somewhat poorly drained soil. The adzuki bean cultivars were cultivated in the paddy field from 2015 to 2016 in Milyang, Gyeongsangnam, Korea. Average soil moisture content was 16.5% in 2015 and 31.0% in 2016 at the experimental site during adzuki bean cultivation. As the soil moisture content increased, most of the adzuki bean cultivars showed deceases in stem height, first setting pod node, number of pods, 100 seed weight, and yield. Chungju-pat produced the greatest yields among the 11 cultivars in 2015 and 2016, whereas Hongeon had the smallest yields. Adzuki bean yields after paddy field cultivation was lower for all cultivars than for adzuki bean yields from the same cultivars after upland field cultivation. Chungju-pat and Chilbo-pat showed the smallest decreases in yields after paddy field cultivation, whereas Hongeon and Kumsil showed the greatest yield reductions. There were no significant differences in proximate composition. Some mineral components ($P_2O_5$, Ca, and Mg) were statistically different across cultivars. Chungju-pat had the highest Ca and Mg contents, but antioxidant components (polyphenol and flavonoids) and antioxidant activities (ABTS and DPPH) were highest in Saegil and lowest in Jungbu-pat. PCA and clustering analyses, based on the growth, yield, and antioxidant component measurements, performed to identify which variables contributed the most to separating adzuki bean cultivars or to grouping cultivars with similar characteristics. These analyses showed that the antioxidant components and antioxidant activities had the most influence on grouping cultivars together. Among the 11 cultivars, Saegil was statistically different from the other cultivars, but the other 10 cultivars were not significantly different under paddy field cultivation. Soil moisture content affected adzuki bean yield and antioxidant component contents. An increase in soil moisture led to a decrease in yield, but an increase in antioxidant components. These results provide information that will improve the selection of an appropriate adzuki bean cultivar for use in paddy fields.

• Korean journal of applied entomology
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• v.48 no.3
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• pp.335-345
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• 2009

Effect of four nematicidal herbal extracts (Daphne genkwa, Eugenia caryophyllata, Quisqualis indica and Zingiber officinale) and 3 acricidal herbal extracts (Pharbitis nil, Xanthium strumarium, and Desmodium caudatum) on entomopathobenic nematodes [Steinernema carpocapsae Pocheon strain (ScP) and Heterorhabditis sp. Gyeongsan strain (HG)], silkworm (Bombyx mori), and ground beetles (Synuchus sp.) were investigated in the laboratory and field. D. genkwa was highly toxic to SCP and HG (100% mortality) at the concentration of 5,000 ppm in X-plate. All the infective juveniles of HG were dead after 3 days by E. caryophyllata and Q. indica. The mortality of ScP and HG was below 10% by D. genkwa, D. caudatum, E. caryophyllata, Q. indica and Z. officinale at the concentration of 1,000 ppm two days after treatment while mortality of HG was 62.8% by D. genkwa at the concentration of 1,000 ppm in X-plate. However, 1,000 ppm had not effect on nematode survival and pathogenicity of ScP in sand column. On the contrary, E. caryophyllata had effect on pathogenicity of HG. Mean number of dead Galleria mellonella larva of HG was 0.5 in E. caryophyllata treatment. Q. indica did not effect silkworm reared on mulberry leaves at the treatment of 1,000 ppm in 10 days after treatment. However, there were 20.0 and 100% mortalities in the treatment of D. genkwa 3 and 10 days after treatment, respectively. The weight of silkworm was low in D. genkwa and did not pupate. The weight of pupa and cocoon were not different in E. caryophyllata, P. nil, Q. indica, X. strumarium and Z. officinale. D. genkwa, E. caryophyllata, P. nil, Q. indica and Z. officinale had no effect on ground beetles, Synuchus sp. in forest soil.

• Journal of Bio-Environment Control
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• v.13 no.4
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• pp.200-208
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• 2004

Effects of cucumber and tomato seed germination by previous leaf and root vegetables (cabbage, radish, welsh onion, lettuce) residue in soil were tested in pot condition. Overall, suppression effect of welsh onion residue was the greatest in 4 tested crop residue and followed by radish, cabbage and lettuce, but lettuce residue didn't have effect on cucumber seed germination. Suppression were maintained ca. 20 days but after the time point, growth of cucumber and tomato were enhanced. Enhancing effect of welsh onion residue was the greatest in 4 tested crops residues and followed by radish, cabbage and lettuce. As a conclusion, residue of welsh onion, radish and cabbage were suppressed the germination of cucumber and tomato seeds but enhanced growth after 20 days of treatment. To verify the effective concentration of residue on suppression of germination and growth of radicle of cucumber and tomato, plant extract of welsh onion, radish, cabbage and lettuce were diluted as 5, 10, 17, 23, 35, 50, and $65\%$, and then tested. In low concentration treatment, 5, 10, 17, and $23\%$, all 4 crop extracts didn't suppress cucumber seed germination. High concentration of lettuce extract, 35, 50, and $65\%$, cucumber seed didn't germinate at all. In case of welsh onion extract, only $65\%$ treatment suppressed cucumber seed germination. In low concentration treatment, 17, and $23\%$, only the welsh onion extract suppressed young radicle. In case of high concentration treatment, except $35\%$, all four crops extract suppressed cucumber radicle growth. In low concentration treatment, tomato seed germination was suppressed by lettuce extract only but in high concentration treatment, 35, 50, and $65\%$, all extracts suppressed germination. Especially higher than $50\%$ treatment, tomato seed didn't germinate at all. Radicle growth was highly suppressed in welsh onion and lettuce extract, higher than $23\%$ concentration. As conclusion, leaf and root vegetable extracts suppressed cucumber and tomato seed germination and in high concentration, also suppressed radicle growth.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.2
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• pp.85-90
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• 2013

This study was conducted to examine the basis for the information to select the suitable potato varieties grown in new reclaimed land. The potatoes of five varieties were planted in the port with 4 different electrical conductivities of saturated extracts of soil taken the Saemangeum reclamation area, which was made of non-treatment salt and three concentrations of salt treatment, 1.6 dS $m^{-1}$, 3.2 dS $m^{-1}$, 4.8 dS $m^{-1}$, respectively. All of the potato varieties were uniformly emerged without missing plant in all treatment groups, even 4.8 dS $m^{-1}$ treatment group. According to the salt concentration of soil, required date to the emergence of the potato comparing to non-treatment salt was delayed 3-4 days in 1.6 dS $m^{-1}$, 6-10 days in 3.2 dS $m^{-1}$, 7-13 days in 4.8 dS $m^{-1}$, respectively, and the number of its branch decreased by 14-58% comparing to non-treatment salt depending on varieties. Since the increase of the salt concentration of the soil was more serious the decrease of the number of its branch, but plant height tended to increase when branch number per plant was small, which was depending on more number of its branch than salt concentration. Fresh tuber yield of potato comparing to non-treatment salt were decrease 33.7% in 1.6 dS $m^{-1}$, 59.5% in 3.2 dS $m^{-1}$, 79.3% 7-13 days in 4.8 dS $m^{-1}$, respectively. The threshold EC starting the growth inhibition of fresh weight decreased was 1.2 dS $m^{-1}$ for Chudong, 1.8 $m^{-1}$ for Chubeak, 1.9 $m^{-1}$ for Chugang and Chuyeong, and 2.0 $m^{-1}$ for Sumi, and EC which decreased 50% of dry weight index was 2.4 dS $m^{-1}$ for Chubaek, 2.45 dS $m^{-1}$ for Chudong, 2.81 dS $m^{-1}$ for Chugang, 3.03 dS $m^{-1}$ for Chuyeong, and 3.29 dS $m^{-1}$ for Sumi. The present results suggest that Sumi is considered to the suitable potato variety grown on saline soils.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.2
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• pp.158-163
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• 2006

Young radishes (YR, yeolmu in Korean) were cultivated in the soil with and without sulfur. YR-Control (without sulfur) was grown in the normal soil. YR were grown in the soil with $1,818\;g/m^3$ sulfur (YR-A) and $1,818\;g/m^3$ sulfur added lime mortar (YR-B) on it, respectively. Also, we prepared YR kimchis using YR-Control, YR-A and YR-B. The kimchis were fermented at $5^{\circ}C$ for 8 weeks. The growth inhibitory effects of AGS human gastric adenocarcinoma cells of the YR samples and kimchis were investigated. YR kimchis after $4\~5$ weeks at $5^{\circ}C$ showed higher acidity of $0.88\~1.20\%$ with pH $4.3\~4.5$ and the YR kimchis kept approximately pH 4.0 until 8 weeks. The kimchi A and B using YR-A and YR-B showed faster fermentation time, higher level of Leuconostoc sp. and lower level of Lactobacillus sp. during the fermentation, comparing to the control kimchi using YR-Control. Juices from YR-A and YR-B showed higher growth inhibitory effects of AGS human gastric adenocarcinoma cells than the juice from YR-Control at the same concentration. The growth inhibitory effect of YR-A was similar to that of the YR-B. The kimchi A and B juices also exhibited higher inhibitory effects $(74\%)$ on the growth of AGS human gastric adenocarcinoma cells than that of the control kimchi $(57\%)$ at the higher concentration of $20{\mu}L/assay$. Methanol extracts from the YR-kimchis also led to the similar results to the results of the juices. These results suggested that preparing of kimchi using differently cultivated YR especially in the soil with sulfur, which can help to synthesize sulfur-containing compounds, could increase the growth inhibitory effects of AGS human gastric adenocarcinoma cells.