• Korean Journal of Weed Science
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• v.30 no.4
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• pp.445-453
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• 2010

This study was conducted to investigate herbicidal efficacy and diffusibility of halosulfuron-methyl+mefenacet in water treated with 500 g great granule (GG) and 3 kg granule (GR). The 500 g GG was been spreading on the surface of the water within 6 minutes, 53 seconds, and it's active ingredient was diffused in the water bath of $10m^2$ size between 30 and 60 minutes. In addition, the diffusion of 500 g GG was influenced by moisture contents, so it have to immediately use 500 g GG in paddy fields when it was been unpacked. The herbicidal efficacy of the 500 g GG and 3 kg GR of halosulfuron-methyl+mefenacet was excellent to most weed species, but showed different efficacy for the control of Aneilema keisak and Scirpus juncoides, that was may be distribution pattern of active ingredient as different formulation.

• Weed & Turfgrass Science
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• v.2 no.4
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• pp.352-357
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• 2013

A survey was performed to investigate major paddy field weeds and frequently used herbicides in Gyeonggi province, Korea in order to establish a system to efficiently control herbicide-resistant weeds. The dominant paddy field weeds included Echinochloa spp. (22%), Eleocharis kuroguwai (14%), Sagittaria trifolia (13%), Scirpus juncoides (12%), Monochoria vaginalis (9%) and Sagittaria pygmaea (7%), and the most widely used herbicides were butachlor 33% CS (25%), benzobicyclon + fentrazamide + imazosulfuron 11.5% SC (9%), cyclosulfamuron + mefenacet 22.2% SC (9%), butachlor 5% GR (6%), and oxadiazon 12% EC (6%) in Gyeonggi province, Korea. Many paddy rice growers considered S. juncoides, M. vaginalis, S. pygmaea and C. difformis as herbicide-resistant weeds. An extensive research deserves to be conducted to monitor occurrence of herbicideresistant paddy weeds in Gyeonggi province, Korea.

• Korean Journal of Environmental Agriculture
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• v.33 no.1
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• pp.17-23
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• 2014

BACKGROUND: Crop rotation is often used as a solution to eradicate nematodes in soils used in plastic film houses for long-term cultivation of oriental melon. However, it is not clear if the double-cropping is effective in reducing nematode populations in soils. METHODS AND RESULTS: Nematode population in plastic film house soil was measured during oriental melon cultivation from April to July in short term crop rotation systems of oriental melon. Double-cropping of chinese cabbage in open-field for 3-4 months following oriental melon in plastic film houses could not prevent the build-up of high population density of nematodes. However, double-cropping of dropwort in flooded soil for 3-4 months following oriental melon in plastic film houses could effectively reduce the nematode population during the successive year of oriental melon cultivation. The reduced nematode population in soils of oriental melon-dropwort double-cropping system was continued until the mid season of progressive year oriental melon cultivation. Application of nematicide to soil before growing oriental melon in the oriental melon-dropwort double-cropping was very effective in preventing the build-up of high population density of nematode in plastic film house soils. CONCLUSION: Short-term introduction of crop rotation was not effective in suppression of high population density of nematodes in plastic film house soils of long-term year-to-year production of oriental melon. For securing the soil productivity and sustainability of plastic film house, various physical, chemical, and agronomic practices should be properly combined together.

• Weed & Turfgrass Science
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• v.4 no.2
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• pp.85-94
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• 2015

The weed flora in the mulberry fields were investigated in Suwon, Jeonju, and Buan in May, July, and September of 2014. The objectives of this study were to use the survey data for establishing weed control methods and to bring awareness of possible problematic weeds in the Korean mulberry fields. The survey was conducted in 53 regions, covering approximately $145,925m^2$. Altogether 153 weed species of 37 families were identified, of which 68 were annual, 39 species were biennial and 46 were perennial. The dominance was the highest with Digitaria ciliaris followed by Erigeron annuus, Chenopodium album, Echinochloa crus-galli var.crus-galli, Acalypha australis, Commelina communis etc. Exotic weeds presented 44 species with 28.8% of a total presence, of which Erigeron annuus was the highest, followed by Chenopodium album, Phytolacca americana, Conyza canadensis, Oxalis corymbosa etc. Especially, we should aware Senecio vulgaris, not controlled with glufosinate ammonium SL in the Korean mulberry fields because it was known as atrazine resistance in US, Canada, Germany etc. In the PCA plot, weeds presented in the mulberry fields were divided into two groups, Eclipta prostrata community and Stellaria aquatic community and weed flora of Suwon and Buan were different due to those only presented in Suwon.

• Korean Journal of Organic Agriculture
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• v.24 no.4
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• pp.919-929
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• 2016

This study investigated the effect of organic materials (Bordeaux, Loess-sulfur) and the removal of apical shoot against downy mildew disease on cucumber cultivated in greenhouse. Five kinds of Bordeaux were made by adjusting mixing ratio of lime and copper sulfate in order to elucidate the optimal combination. The 4-6type Bordeaux was selected as the most effective combination for controlling cucumber downy mildew. Loess-sulfur showed inhibitory activity against cucumber downey mildew, but it was less effective than Bordeaux. It was confirmed that apical shoot cutting could reduce the incidence of cucumber downy mildew disease by 56.3%. When apical shoots of susceptible cucumber variety were cut at different leaf stages, disease incidence by early apical shoot cutting treatment was lower than that of late apical shoot cutting treatment. However in a resistant variety, 'Heukryungsamcheok', disease incidences of all cucumber apical shoot cutting treatments were lower than that of non-cutting treatment, but there was no differences between apical shoot cutting treatments due to low disease incidences. In addition, when organic materials and apical shoot cutting treatment were carried out in parallel, the combined treatments of organic materials and apical shoot cutting showed low disease incidence of cucumber downy mildew compared to untreated control. The lowest disease incidence of cucumber downy mildew was recorded in the combined treatment of 4-6type Bordeaux and apical shoot cutting. This study confirmed that apical shoot cutting can reduce the disease incidence of cucumber downy mildew and the combined treatment of apical shoot cutting and organic materials showed higher suppressive effect against cucumber downy mildew.

• The Korean Journal of Ecology
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• v.22 no.5
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• pp.235-240
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• 1999

Characterization of water quality was performed from March 1993 to March 1998, on the purpose of clarifying the relationships between water quality and land use types. The study sites were two reservoir basins; Kaesim and Jangchan in Iwon-myon, Okchon-gun, Chungcho'ngbukdo Province. The two basins were characterized by cultivated area (Kaesim reservoir) and mountain area (Jangchan reservoir), and divided into eleven small basins, where dynamics of pollutants, and the relationship between water quality and land use types were investigated. BOD, SS and TKN became lower and lower from up-stream to down-stream, except for the small basin G where self-purification limit was exceeded. And water quality of Jangchan reservoir basin was worse because of fish nursery. Area below altitude 200m occupied 56% in Kaesim and 44% in Jangchan reservoir basins. Especially total phosphorous (Y/sub T-P/=0.2023X＋0.0991, r=0.54) and total nitrogen increased in small basins where the proportion of cultivated and residential area was higher. The analysis of influences of pollutant discharge on water quality showed that pollution charge was very high in cultivated areas. The concentrations of pollutants were attenuated flowing into watersheds through physical, chemical, biochemical, and biological processes. The pollution level of mountain area was lower than that of cultivated areas.

• Korean Journal of Environmental Biology
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• v.25 no.3
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• pp.223-227
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• 2007

Crop loss and damage by wildlife are becoming more serious to residents inside and around National Parks of Korea annually. It could be caused by small size of Parks, which is couples of ten $km^2$ only, and more than a third of total parks' areas are belonging to privates. Wild boar (Sus scrofa) is one of the most harmful pests in nationwide. Treading down crop field using as bedding or resting site are major damaged types and foraging behavior is following. Besides of boars, Korean water deer (Hydropotes inermis), racoon dog (Nyctereutes procyonoides), and badger (Meles meles) are another serious pests. Mainly, farm products planted in upland, such as corns, sweet potatoes, cabbages, etc. are harmed easily, a rate reaches up to 76.9% of whole losses. 92.4% (n=187) of interviewees, who are mostly seniors, cultivate small crop fields smaller than 1 ha. Crop damage would be started from June to late November, time differences are happened due to latitude, climate condition, and crop differences of National Parks. Dusting animal repellents are easier and widespread methods to prevent animal foraging to crop fields and installing noisy makers using gun powder and setting up scarecrows are traditional methods for repelling animals. Nevertheless, effects of these self-defence are turned out to be useful soon after labors done only. Since legal compensation for crop damages by wildlife are not prepared systematically so far, crop loss are rarely reported to local government by most farmers. Systematic and objective methods for quantifying of crop loss by wildlife and population managements system should be offered urgently to well-managed animals habitat and residents' living inside National Parks.

• Weed & Turfgrass Science
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• v.4 no.4
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• pp.405-412
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• 2015

Forty schools having natural turf playgrounds were investigated by on-spot investigation and oral interviews with relevant school officials to find out basic information on turfgrass management practices of school playgrounds in Gyeonggi province. Average area of playground was $3,890m^2$ per school and $12m^2$ per student. Ninety five percent of turf playgrounds were managed by school staff and ninety percent of schools spent less than 5 million won per year for turf management. The difficulties in turfgrass management were considered as a major challenge for the schools, followed by turfgrass management cost. Among the management practices, school officials pointed out weed management as the most difficult work, followed by irrigation. The average number of fertilization and mowing was 2 and 6 times per year, respectively. About the half of playgrounds were irrigated only when there was wilting symptom. Zoysiagrass was the most popular choice for the school playgrounds and only three school playgrounds were established with pop-up irrigation system. Fourteen school playgrounds had good turf quality but the rest of school playgrounds had inadequate turf quality requiring minor or full renovation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.2
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• pp.243-249
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• 1996

To formalize the mechanization technique so as to build up competitiveness on the international market, a detail survey of a 104ha size rice farm, was made. And calculated to find out how many machine of each calibre are needed. It was found that he needed : 3 farm tractors, 3 combines, 4 grain dryers, 1 speed sprayer, 100 man days of labor for sowing, application of fertilizer and herbicide, respectively. And also needed 150 man days for combine harvesting and 60 man days for disease and pest control. It was found also that well timed harvesting is critically needed to keep rice quality. Because, in case when harvesting machine was beakdown to make harvesting time extended, then the quality drops down very much and also the farm income fall very much. Therefore, it is recommended that the amount of machine needed should be prepared and they should be well maintained so that harvest be completed in time.

• Korean Journal of Agricultural Science
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• v.26 no.1
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• pp.6-11
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• 1999

This experiment was carried out to estimate the appropriate seedling stand and to find out the factors of good establishment and the reason of the reduction of yield by water foxtail. The seedling stands was improved by the ice straw mulching and treading by the tracks of combine. The effect of mulching was higher than the treading. The appropriate seedling stands for example yield were estimated about 507 plants per $m^2$ and its yield was 24kg/10a. The higher density of water foxtail, the less the grain yield; 21.8% by 17 to 22 water foxtail stands per $m^2$ and 11.0% by 6 to 11 plants.