• Korean Journal of Organic Agriculture
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• v.22 no.4
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• pp.761-771
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• 2014

The study was conducted to evaluate effects of weed managements after false seedbed on the weed control and growth of spring and fall cabbages (Brassica oleracea L.) in an organic upland in 2013. Weed managements included rake, flame, PE mulch, and none treatment. The weed occurrence was not effectively controlled by rake treatment but controlled by flame treatment in spring and fall cultivation. PE mulch plots had 30% of tip-burn in spring cultivation. Weed managements after false seedbed were similar fresh weight, leaf number, and cabbage yield to the conventional PE mulch. Head of cabbage was the lowest on the none treatment. Fall cultivation reduced the weed density and increased yield of cabbage compared to those of spring in all treatment plots. In conclusion, rake or flame treatment after false seedbed markedly decreased weed occurrence, which was expected to use for management of environmentally-friendly vegetation as a substitute of PE mulch.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.2
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• pp.159-164
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• 2019

Weed control is a crucial practice not only in organic farming, but also in modern agriculture because it can lead to loss in crop yield. In general, weed is distributed in patches heterogeneously in the field. These patches vary in size, shape, and density. Thus, it would be efficient if chemicals are sprayed on these patches rather than spraying uniformly in the field, which can pollute the environment and be cost prohibitive. In this sense, weed detection could be beneficial for sustainable agriculture. Studies have been conducted to detect weed patches in the field using remote sensing technologies, which can be classified into a method using image segmentation based on morphology and a method with vegetative indices based on the wavelength of light. In this study, the latter methodology has been used to detect the weed patches. As a result, it was found that the vegetative indices were easier to operate as it did not need any sophisticated algorithm for differentiating weeds from crop and soil as compared to the former method. Consequently, we demonstrated that the current method of using vegetative index is accurate enough to detect weed patches, and will be useful for farmers to control weeds with minimal use of chemicals and in a more precise manner.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.3
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• pp.19-30
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• 1978

Use of herbicides in Korean agriculture has increased rapidly in recent years accompanying with ever-increasing pressure of farm labor shortage. Herbicides occupied already the second place in the rank of pesticides consumption in 1977. The agricultural experiment stations have carried out over 50 trials of chemical weed control each year since 1968. These research works and registration trials contributed much to the present wide use of herbicides. The pesticide management act amended in 1977 requires reevaluation of pesticides for their efficacy every 5 year-term. However, the development of sound weed control program and recommendations has been hempered very much by the lack of qualified workers of weed control research in agricultural experiment stations and in the institute for pesticide registration trial. Critical review of the past research works on herbicide evaluation and the present status indicates strong need for 1) the characterization of the nature of local and national weed problem, 2) the improvement of ability of the staffs in charge of weed control research through appropriate training on the basics and experimental techniques, and 3) organization and activities of weed control research committee. Furthermore, the present article attempts to clarify commonly misled points in the establishment of herbicide evaluation plan, in the design and execution of field trials, and in the assessment of trial results of the past works from the viewpoint of the basic principles with some case studies for resolution of specific enigmas.

• Korean Journal of Weed Science
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• v.30 no.3
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• pp.272-281
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• 2010

The objective of this research was to find out the weed management techniques in environment-friendly rice paddy fields through the study on herbicidal effects and problems of various organic materials. This experiment was conducted under different conditions of weed species and weed densities in environment-friendly rice paddy fields. There was no difference in weedy efficacy on golden apple snail (GAS), paper mulching (PM), and machine weeding (MW) between low and high weed densities. However, the effect of weed control in rice bran (RB) and effective microorganism (EM) + molasses was higher in high weed density than in low weed density. In general, the effect of weed control as affected by various organic materials was in the order of GAS (97-100%) > PM (93-98%) > RB (15-80%) > EM (7-31%). GAS provided excellent control of all weed species tested except for Persicaria hydropiper. PM gave acceptable control of the weed species except for Echinochloa crus-galli, Ludwigia prostrata, and Eleocharis kuroguwai. However, MW gave fair control (70% biomass reduction) of all weed species tested. BR followed by MW or EM followed by MW treatments had similar effect on weed control compared to each treatment alone. However, BR followed by GAS or EM followed by GAS provided 100% control of weed species tested. The level of rice foliar injury caused by various organic materials was in the order of GAS and MW (10-20%) > RB (10-15%) > PM and EM (5-7%). Typical symptoms of organic materials are wilting, inhibition of growth, missing hill, and reduction of tiller. Cost for weed control of GAS, RB, EM, and PM were 2.1, 3.1, 2.3, and 13.2 times higher than that of the herbicide. These data indicate that GAS was the best method for weed management in environmentfriendly rice paddy fields. Further study is required to elucidate the mechanisms underlying the rice injury as affected by GAS.

• Proceedings of the Ginseng society Conference
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• 1998.06a
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• pp.103-108
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• 1998

The Canadian production of American ginseng (Panax quinquefolius L.) occurs mainly in Ontario, British Columbia and the Atlantic provinces. Although ginseng is a profitable crop, its successful production is dependent on careful consideration of cultural management f include site selection, site preparation, seed selection and handling, shading actors which and mulching, pest and nutritional management, and handling of harvested crops. Diseases of particular concern in Atlantic Canada are root rots caused by Phytopkthora cactorum, Cylindrocarpon destructans and Fusarium sp. Recently two systemic fungicides (metalaxyl and fosetylal) were registered; however, growers in Atlantic Canada have experienced metalaxyl resistance resulting from the reliance on this single compound for the control of Phytophthora sap. Current research being conducted on alternative control of these diseases will be discussed. In weed control research, 2, 4-D, MCPA, clopyralid have continued to show promise for weed contro1 at low rates. In trials to evaluate non-selective herbicides as post-senescence or pre-emergence in ginseng, glyphosate (Round-up) provided control of perennials as well as willowherb and lambsquarters. In phytoxicity trials, ginseng significantly tolerated grass herbicides, including clethodim, rimsulfuron, trakloxydim, nicosulfuron and fenoxyprop. For broadleaf herbicides, significant tolerance was shown for bromoxynil, thifensulfuron methyl, flumetulam/clopyralid, thifensulfuro/tribenuron. Disease and weed management of ginseng in Atlantic Canada will be discussed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.4
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• pp.271-278
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• 2021

Azolla is a genus of small aquatic ferns native to Asia, Africa, and America. Azolla is potentially significant as a nitrogen source in agriculture, particularly in conjunction with rice (Oryza sativa L.) cultivation. In addition, Azolla may either control weeds or act as a weed depending on management; therefore, we aimed to determine the effect of Azolla incorporation on weed (e.g., Monochoria vaginalis, Rotala indica, Aeschynomene indica, and Cyperus amuricus) control and its other benefits during rice cultivation. The effects of Azolla on weed emergence were evaluated based on plot area coverage by the Azolla mat, which appears as a green sheet over water, and the rate of weed emergence in paddy field. Weed occurrence was investigated 40 days after Azolla inoculation. Soil samples from the experimental plots were collected following harvest in 2014-2015, and analyzed. Moreover, rice growth, yield, and grain quality were measured. Azolla suppressed weed growth by 72%. Azolla mat incorporation in rice fields suppressed weed growth by over 60%. In addition, Azolla promoted nitrogen fixation. Compared with nitrogen management using chemical fertilizers, Azolla incorporation showed the potential for various positive effects, including the improvement of soil fertility by increasing total nitrogen, and organic matter content. Rice grown with Azolla maintained its yield without additional herbicide treatment. Moreover, the palatability of cooked rice was better when grown with Azolla.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.1
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• pp.1-7
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• 2003

In spite water direct seeding cultivation of rice has advantages in terms of laborsaving and cost-down, it demonstrates uneven seedling establishment and difficult weed management. To select an applicable mat for mulching system of water seeded rice, weed occurrence, growth and yield performances of rice, and soil temperature were evaluated in several kinds of biodegradable mulching material. Field studies were conducted at the experimental farm of National Crop Experiment Station in 1999 and 2000. Among the mats tested in 1999, Safer-mat had the greatest effect on inhibiting weed occurrence and Lawn-mat demonstrated the least efficacy of weed control (EWC) value. In Safer-mat treatment, Ludwigia prostrata was the dominant weed species but Echinochloa crus-galli was not observed. Different kinds of mulching material from the mats studied in 1999 were tested in 2000. Biodegradable polyester (PES) coated on the recycled paper for newspaper press (RP) treatments showed similar or higher EWC values than non-mulched broadcast seed rice with 2 times of herbicide application (BC-herbicide) and Safer-mat that was the most effective mat on preventing weed appearance in 1999. Immediately after mat mulching on the surface of paddy soil, five pregerminated rice seeds were manually sown in each 3cm-hole formerly punctured at 30${\times}$14 cm spacing in 2000. All the 3 kinds of mulching material tested in 2000 had better seedling stand than BC-herbicide treatment. Rice yield in PES coated with 10 thickness on RP (PES10 $\mu\textrm{m}$＋RP) was a little higher than in BC-herbicide treatment but the former produced less panicles in unit land area than the latter. PES10 $\mu\textrm{m}$＋RP demonstrated a great effect on raising soil surface temperature than non-mulching treatment throughout the period of seedling establishment.

• Korean Journal of Agricultural Science
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• v.42 no.2
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• pp.111-116
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• 2015

Combined applications of rice bran with pine leaves were tested to examine the inhibitory effects to paddy weeds and increased yield of rice for developing techniques of environment-friendly weed management in paddy rice fields. Weed control efficacy at 60 days after treatment was improved to 88.8% by combined application of rice bran with pine leaves, while weed control efficacy by single application of rice bran showed 67.5%. The other weed control efficacy combined with chestnut leaves and barley straws were 76.3% and 69.9% respectively. Combined application of rice bran with pine leaves was more effective to broadleaf weeds such as Monochoria vaginalis. Weed control efficacy by combined application with pine leaves was 100% until 70 days after rice transplanting and maintained weed control effect up to 90 days after transplanting. Rice yield by combined application of rice bran with pine leaves was 526 kg/10 a, which was higher yield than by combined application with barley straws, single application of rice bran, natural snail application and hand weeding.

• Journal of Korean Society of Forest Science
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• v.109 no.2
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• pp.195-201
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• 2020

A forest operation is considered as one of the riskiest environments for the development of musculoskeletal disorders because operators are exposed to harmful environmental conditions such as rough terrain, inclement weather, and poor working postures. In weed and kudzu removal operations, manual application is still common in Korea. In this study, we evaluated the ergonomic conditions of weed and kudzu removal in regeneration forests and the associated risk of musculoskeletal disorders. The risk of musculoskeletal disorders was evaluated using the Ovako Working Posture Analysis System and postural risk index. Postural risk was significantly higher for kudzu compared with weed removal operations. This suggests that kudzu removal operations must be improved to decrease postural risk.

• Korean Journal of Environmental Agriculture
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• v.27 no.1
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• pp.72-79
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• 2008

Phytosociological study was carried out to investigate the structural characteristics of Humulus japonicus community in the Middle area of Korea. The vegetation data of total 67 $relev\acute{e}s$ were analyzed by the $Z\ddot{u}rich$-Montpellier school's method. Upper layer plant communities of Humulus japonicus were classified into four community groups : Humulus japonicus-Artemisia princeps community, Chenopodium album community, Setaria viridis-Echinochloa crus-galli community and Typical community. Lower layer plant communities were classified into five community groups : Galium spurium-Stellaria aquatica community, Equisetum arvense community, Persicaria theunbergii community, Echinochloa crus-galli-Digitaria ciliaris community and Typical community. According to the results of canonical correspondence analysis by vegetation and environmental factor, Setaria viridis-Echinochloa crus-galli community of upper layer was distributed throughout the soil with high relative light and soil hardness. Chenopodium album community appeared in the soil with high pH. Galium spurium-Stellaria aquatica community of lower layer was formed in the high soil pH. Persicaria theunbergii community and Echinochloa crus-galli-Digitaria ciliaris community were distributed in the soil with high moisture.