• Korean Journal of Weed Science
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• v.30 no.3
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• pp.243-251
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• 2010

The study was conducted to evaluate the weed suppressing effects of two winter cover crops, Chinese milk vetch (CMV) and rye, in minor cereal fields in 2009. The suppressing activities of cover crops were due to the allelopathy of cover crops during weed emerging periods and competitive activity during vegetative growth of weeds. Weed suppression by cover crops were changed from 26.5 g $m^{-2}$, 0.1 g $m^{-2}$ and 0.2 g $m^{-2}$ in control, rye field and CMV field, respectively, on June 22 to 428.6 g $m^{-2}$, 1 g $m^{-2}$ and 403.9 g $m^{-2}$ in control, rye field and CMV field, respectively, on July 22. The weed dry weights were further changed to 656.3 g $m^{-2}$, 607.8 g $m^{-2}$ and 511.8 g $m^{-2}$ in control, rye field and CMV field, respectively, on August 22. The suppressing effect of cover crops also observed in minor cereals. Plant height and dry weight of sorghum was reduced to 68.7% and 33.6% of handweeding, respectively, on August 5. The reduction was recovered to 82.7% and 55.6% of control, respectively, on August 26. In addition, heading date of minor cereals was delayed by 7 days with rye.

• Weed & Turfgrass Science
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• v.6 no.2
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• pp.130-135
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• 2017

In the current study, we surveyed the status of graveyard lawn maintenance in Korea. The lawn maintenance information was obtained from the vicarious companies registered on the internet portal site and the Forestry Federation of Korea, and the questionnaire investigation from Primary Agricultural Cooperatives (Nonghyup). In all provinces surveyed, individual graves were maintained on a $66m^2$ (20 Pyeong) basis. The vicarious maintenance of graveyard lawn was carried out 1~5 times a year, and the maintenance cost increased as the number of times increased. Mowing the grass around a grave (Beolcho) was mainly done before the Korean Thanksgiving Day (Chuseok). The number of Beolcho was steadily increased from 2013 to 2015, and the price was getting higher and higher. Gyeonggi province had the highest cost, and Jeolla had the lowest cost. Regardless of the year, the number of orders received were higher in Gyeongnam > Gyeongbuk > Jeonnam province in order. Most of the reason for requested Beolcho was because the client lives in the area far from the graveyard. The direction of the cemetery was very varied. According to the survey, the all grass were zoysiagrass (Zoysia japonica), and grass coverage rate of the graves was 35.4~71.9%. Through questionnaire investigation, the reason why the density of grass was lowered was because the periodic management of weeds and fallen leaves was insufficient. Further research on the maintenance of graveyard in the future will be necessary.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.4
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• pp.301-308
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• 2010

This study was carried out in the Chungnam National University grassland experimental field from October, 2007 to December, 2009 in order to find out the growth characteristics, seasonal anthesis distribution and botanical composition of the wildflowers which were altogether composed of 70% sheep fescue and 30% introduced wildflowers. The experimental species contained 23 species in total to which sheep fescue (fundamental turfgrass) and 22 introduced wildflowers belonged. At the time of the anthesis of the wildflowers, the average plant height was 29.7 cm at first growing season and 34.1 cm at second growing season. They bloomed out into eight colors, but into simplified two colors during August, September, and October. The blooming season leant toward April and June and from August there were lots of difficulties in the wildflower blooming and the maintenance of their consistency. The botanical composition of wildflowers, sheep fescue, and weeds were 21%, 64%, and 15% in the first growing season (2008) and 19%, 65%, and 16% respectively, in the second growing season (2009). Based on this result, cultivating the introduced wildflower grassland has more difficulty because there is some difficulty in the wildflower seasonal distribution and the maintenance of its consistency. And thus, the introduction of more various wildflower such as perennials and flowers blooming after summer, and the seed-mixture combination method should be studied.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.3
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• pp.227-236
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• 2010

This study was carried out in order to find out the growth characteristics, the seasonal anthesis distribution and the botanical composition of the wildflower pastures which were altogether composed of 90% sheep fescue and 10% wildflowers in the Chungnam National University experimental field from October, 2007 to December, 2009. The experimental species contained 34 species in total consisting of sheep fescue (fundamental turfgrass), 4 native wildflowers, and 29 induced wildflowers belonged. At the time of the anthesis of the wildflowers, the average length was 28.7 cm one year later and 36.7 cm two years later. They bloomed out into from six to nine colors, but into one or three colors during August, September, and October. The blooming season leant toward May and June, and from August, there was lots of difficulty in the wildflower blooming and the maintenance of their consistency. Especially, at the age of two (2009) the color, seasonal distribution, and consistency emerged as problems owing to the reduction of annual wildflowers after winterization. The annual botanical composition of wildflowers, sheep fescue, and weeds came to 22%, 68%, and 10% each one year later (2008) and 19%, 72%, and 9% each two years later (2009). Based on this result, cultivating wildflower in grassland (90% sheep fescue and 10% wildflowers) is the proper method not only for maintaining green space, to prevent soil erosion by sheep fescue, but also for commanding a fine view of wildflowers.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.3
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• pp.217-226
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• 2010

The purpose of this study was to suggest the growth characteristics, seasonal distribution and botanical composition of wildflower pastures. The experimental wildflowers were 34 species (1 turfgrass species, 4 native wildflower species and 29 introduced wildflower species). The experiment was administered in the Chungnam National University experimental field from October, 2007 to December, 2009 and the result is as follows: The length of the wildflowers was within the range of 7-52 cm and they bloomed into six to ten colors but the species of blooming wildflowers and flower colors and blooming periods were simplified during from August to November. Their tendencies were obviously observed two years later (2009) but among them especially the colors, seasonal anthesis distribution and continuation of wildflower became a problem. The botanical composition of wildflowers, turfgrass, and weeds came to 20%, 67%, and 13% each one year later (2008) and two years later (2009) 16%, 72%, and 12% each. Being grounded upon this result, in case of wildflower pastures of autumn seeding, it is more important to maintain the color, seasonal distribution, and permanence of wildflowers occurring due to annual wildflower reduction after wintering in two years, let alone in the establishment year.

• Magazine of the Korean Society of Agricultural Engineers
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• v.14 no.1
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• pp.2535-2548
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• 1972

Instead of fertilizing the lands they moved to find other fertile lands and lived a feudal life agriculture and various machincs played a main role in the land reclamation. The best method of land clearing, the time and capacity in the operation and the effect of growing crops should systematically analized prior to the time of 3rd Five-year Economic Development(1972-1976) in order to cultivate 210,000ha of wasteland or the modernization of our country. The present study was investigated to find out a new working-system of mechanical land clearing and development of fertile soil. The results are as follows: 1) The first stage of productive power increases when weeds were mixed soil in the land clearing work in order to supply organic materials and to make soil swollen instead of burning or just removing. 2) The equipments such as bulldozers, harrows, power tillers and so on should be prepared in order to do a systematic work in the land clearing. 3) The work of pulling-up roots is dependent upon the forms of roots spreading under the ground. The work of the pulling-up of the straight roots was most difficult. But before the roots are pulling-up we do not know the forms of roots. 4) The cutting of soil from upside to under side land clearing method (II) Spent 6 hr 7 min 43 sec per 1 Danbo in doing land clearing and control method spent 4 hr 52 min 30 sec per 1 Danbo in doing land cearing. No significant difference could be found between II treatment type and I treatment type. 5) The volume of soil carried by bulldozer $270.38m^3$ per 1 Danbo in I type and in II type, $368.58m^3$ per 1 Danbo or about 36% increased in II type then in I type. But that is not a significant difference when considering the whole productive power of soil. 6) The land clearing of terrace by bulldozers cannot escape making the embankment slope of about $45^{\circ}$, and 25.3% should be decreased in the area. It is recommended to make use of the embankment slope by planting grass for cows. 7) The time of retary tilling increased 2.3 times or 1 hr 42 min 22 sec per 1 Danbo compared to the timesrequired in the harrowing. Because it mixed the Organic matter on ground and the harrowing of subsoil. 8) The havest of pasture growing on the land reclamation in natural slope is as follows. (a) The none fertilizers with reclaimed block of productivity decresed 1/10 than that of the farmland. Therefore the none fer tilizing in the cultivated pasture is unprofitable. (b) The havest of the manured IV treatment block was the best not only in the kinds of fertilizers but also in the kinds of pasture grass.

• Korean Journal of Environmental Agriculture
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• v.39 no.3
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• pp.246-252
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• 2020

BACKGROUND: Pesticides are broadly used to control weeds and pests, and the residues remaining in crops are managed in accordance with the MRLs (maximum residue limits). Therefore, an analytical method is required to quantify the residues, and we conducted a series of analyses to select and validate the quick and simple analytical method for tolpyralate in five agricultural products using QuEChERS (quick, easy, cheap, effective, rugged and safe) method and LC-MS/MS (liquid chromatography-tandem mass spectrometry). METHODS AND RESULTS: The agricultural samples were extracted with acetonitrile followed by addition of anhydrous magnesium sulfate, sodium chloride, disodium hydrogencitrate sesquihydrate and trisodium citrate dihydrate. After shaking and centrifugation, purification was performed with d-SPE (dispersive-solid phase extraction) sorbents. To validate the optimized method, its selectivity, linearity, LOD (limit of detection), LOQ (limit of quantitation), accuracy, repeatability, and reproducibility from the inter-laboratory analyses were considered. LOQ of the analytical method was 0.01 mg/kg at five agricultural products and the linearity of matrix-matched calibration were good at seven concentration levels, from 0.0025 to 0.25 mg/L (R²≥0.9980). Mean recoveries at three spiking levels (n=5) were in the range of 85.2~112.4% with associated relative standard deviation values less than 6.2%, and the coefficient of variation between the two laboratories was also below 13%. All optimized results were validated according to the criteria ranges requested in the Codex Alimentarius Commission (CAC) and Ministry of Food and Drug Safety (MFDS) guidelines. CONCLUSION: In conclusion, we suggest that the selected and validated method could serve as a basic data for detecting tolpyralate residue in imported and domestic agricultural products.

• Research in Plant Disease
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• v.15 no.2
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• pp.63-67
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• 2009

Rice stripe virus (RSV) is one of Tenuivirus Group, which is carried by small brown planthopper. There is an outbreak of RSV in South Korea at 20Ot, and 2007. The infection caused by RSV had been investigated on weeds around the rice cultivated areas 13 region and 26 site including Jeonbuk Buan and Chungnam Seocheon. There have a doubt as to alternate host of RSV is total 15 Family and 50 Species including Gramineae 24 species of Duksaepul (Alopecurus aequalis), H. sativum var. vulgare etc.. There is identified the infected RSV in Festuca myuros, Alopecurus aequalis, Hordeum sativum var. vulgare, Trisetum bifidum, Echinochloa crus-galli var. crus-galli, Digitaria ciliaris among this species. Deulmuksae is the overwintering exotic weed which sprout in Autumn and wither in Spring and commonly growed as green manure crop or cover crop. In order to identify the infection rate furthermore, 111 samples which were collected at Buan Gyehwa-myeon region, and 50 samples from Seocheon Maseo-myeon in June, 2008, were ELISA tested. The results are 32 positives from Buan, 28.8% infection rate, 8 positives from Seocheon 16.0% infection rate. RSV infection of Deulmuksae is not reported currently, and follow report first describes the Deulmuksae as an alternate host of RSV.

• Journal of Korean Society on Water Environment
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• v.25 no.4
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• pp.589-596
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• 2009

The spectroscopic characteristics and chemical oxygen demand (COD) oxidation efficiencies were investigated for dissolved organic matters (DOM) from diverse sources, which may indirectly affect the concentrations and the quality of DOM found in watersheds. The DOM investigated for this study showed a wide range of the percent distributions of refractory organic matter (R-OM) from 8 to 100%. Relatively high R-OM distributions were observed for the DOM with the source of head water, sediments, paddy soils, field soils, and treated sewage whereas the DOM from livestock waste, reed, weeds, algae, and attached algae exhibited lower R-OM percent distributions. The percent distribution of R-OM had positive correlations with specific UV absorbance (SUVA) and humidification indices (HIX) of DOM. The investigated DOM was classified into four different source groups (i.e., biota, vegetables, soils, sediments) by comparing the synchronous fluorescence spectra. The DOM group from biota source was characterized by a prominent presence of protein-like fluorescence (PLF) whereas fulvic-like fluorescence (FLF) was additionally observed for vegetable-source DOM. FLF became significant for the DOM from both soils and sediments although no PLF was found for soil-derived DOM. A range of COD oxidation efficiency was observed for the various DOM, ranging from 36 to 94% and from 65 to 125% for $COD_{Mn}$ and $COD_{Cr}$, respectively. The results indicate that $COD_{Cr}$ reflects the higher OM concentration than $COD_{Mn}$. However, 95% confidence intervals of the COD oxidation efficiencies were similar for the two types of COD, suggesting that $COD_{Cr}$ may not be the superior OM index to $COD_{Mn}$ in terms of the variability of the oxidation efficiency. No significant correlations were obtained between COD oxidation efficiencies and the spectroscopic characteristics of DOM for this study.

• Korean Journal of Weed Science
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• v.9 no.2
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• pp.123-129
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• 1989

1) Optimum temperature was $15^{\circ}C$ for C. bursa-pastoris, $20^{\circ}C$ for C. album, $30^{\circ}C$ for P. oleracea, A. lividus, E. crus-galli, D. sanguinalis, and 4 showed wide range of germination temperature. 2) Emergence of C. bursa-pastoris, and C. album was best at $14.8^{\circ}C$ of soil temperature, E. crus-galli at $23^{\circ}C$, E. indica, A. lividis and P. oleracea at $27.1^{\circ}C$ and A. retroflexus and D. sanguinalis at $31.1^{\circ}C$. 3) A. retroflexus and P. oleracea started to germinate at 30% water absorption stage and A. lividus, C. album, S. viridis, and D. sanguinalis at 40% and E. indica at 70%. 4) Germination of weed species was decreased as PEG 6000 induced osmotic potential lowered. C. album, P. oleracea, D. sanguinalis, A. lividus, and Solanum nigrum were germinated at -5.0 bar osmotic potential and C. album and P. oleracea were germinated at -7.0 bar.