• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.2
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• pp.79-83
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• 2005

Rice and weed interference in the paddy field caused by resource competition and allelopathy. Evaluation method of active weed suppressive behavior of rice to weed was developed by eliminating light competition at soil condition. Twenty eight days old rice seedlings (6-7 leaf stage) which was grown at saturated, no drainage pot were clipped above $3\~4cm$ from the soil surface. Weeds seeded around clipped rice stem, named ratoon seeding screening method, showed varietal suppressive difference to Echinochloa crus-galli, Echinochloa crusgalli var. praticola and Monochoria vaginalis. Potential allelopathic rice varieties, Sathi, AC1423 and PI312777 showed better suppressive activity to weed seedling growth than Nonganbyeo and Keumobyeo. Weed suppression of one plant of rice cultivars could be evaluated by the cell size of $2.5\times2.5cm$ at rice clipping of seedling 29 days after rice seeding.

• Journal of Crop Science and Biotechnology
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• v.10 no.2
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• pp.79-85
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• 2007

Rice bran application just after transplanting has been increasingly practiced as an herbicide-substitute for organic rice production in Korea. However, this practice is frequently reported to be unsatisfactory in weed suppression. An experiment with five treatments that combines flooding depth, rice bran application dose, and herbicide treatment was done in the paddy field to evaluate whether rice bran application under deep flooding can lead to a successful weed control in compensation for the single practice of rice bran application. Rice bran was broadcasted on the flood water surface just after deep flooding of 8 to 10cm that was started at seven days after transplanting. In the shallow flooding plot without herbicide six weed species were recorded: Monochoria vaginalis, Echinochloa crus-galli, Ludvigia prostrate, Cyperus amuricus, Aneima keisak, and Bidens tripartite. Among the first four dominant weed species, deep flooding significantly suppressed the occurrence of Echinochloa crus-galli and Cyperus amuricus while did not suppress the occurrence of Monochoria vaginalis and Ludwigia prostrate. On the contrary, rice bran application under deep flooding suppressed significantly Monochoria vaginalis and Ludwigia prostrate while didn't exert an additional suppression of Echinochloa crus-galli and Cyperus amuricus compared to deep flooding alone. Rice bran application and deep flooding suppressed complimentarily all the six weed species to a satisfactory extent except for Monochoria vaginalis of which suppression efficacy was 31.9%. Deep flooding reduced the panicle number substantially by inhibiting the tiller production, increased the spikelet number per panicle slightly, and leaded to a lower rice grain yield compared to shallow flooding with herbicide. Rice bran application under deep flooding mitigated the panicle reduction due to deep flooding, increased the spikelets per panicle significantly, and thus produced even higher grain yield in the rice bran application of 2000kg $ha^{-1}$ as compared to the shallow flooding treatment with herbicide. In conclusion, this practice applying rice bran under deep flooding would be promising to be incorporated as an integral practice for an organic rice farming system.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.3
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• pp.192-198
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• 2011

Establishment of mechanized soybean production system without herbicide is required for organic soybean production in recent. Effects of mechanized soybean planting with partial tillage between growing rye living mulch, which was sown in April or early May, on weed suppression, soybean early growth and yield were investigated with different rye sowing dates and locations in 2007 and 2008, respectively. Effect of rye living mulch on weed suppression at 40~50 days after soybean planting was high as much as 70~90% regardless of rye sowing dates. In particular, a strong suppression effect on the occurrence and growth of Echinochloa crus-galli which occupied 60~80% of total weed biomass was observed. Rye living mulch sown on April 9, of which biomass was more than that sown on April 27, inhibited soybean early growth severely and reduced soybean grain yield in 2007. However, soybean grain yield was no t reduced despite suppression of early growth of soybean plant by living mulch sown during from late April to early May compared with conventional planting. Rye sowing before late April was not proper considering tendency of weed occurrence in spring because of unfavorable changes in weed suppression, early growth and grain yield of soybean according to amount of living mulch.

• Weed & Turfgrass Science
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• v.3 no.4
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• pp.299-304
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• 2014

Effects of false seedbed procedures in organic corn field were evaluated as affected by preparation date and method. False seedbed was prepared at May 7, 14, 21, 28 and June 5 with shallow tillage or flame weeding. Weed suppression rate of each treatment was evaluated 3 weeks after sowing. Optimal false seedbed preparation time was between end of May and early in June. Weed suppression rate of early false seedbed preparation was quiet low. Flaming weed treatment was better than shallow tillage. Weed suppression rate by the second treatment was increased approximately 30-60% compared to $1^{st}$ treatment. Weed suppression rate at 3 weeks after sowing was 70-90% by the second false seedbed preparation. The results showed that the false seedbed technique between end of May and early in June preparation has some potential weed control to reduce weed population during crop growth. Therefore late planting time crop such as corn, sorghum and soybean would be possible to apply false seedbed for organic weed control.

• Smart Media Journal
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• v.7 no.3
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• pp.16-21
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• 2018

This paper presents the design and implementation of a deep learning-based automated weed detector on onion fields. The system is based on a Convolutional Neural Network that specifically selects proposed regions. The detector initiates training with a dataset taken from agricultural onion fields, after which candidate regions with very high probability of suspicion are considered weeds. Non-maximum suppression helps preserving the less overlapped bounding boxes. The dataset collected from different onion farms is evaluated with the proposed classifier. Classification accuracy is about 99% for the dataset, indicating the proposed method's superior performance with regard to weed detection on the onion fields.

• Korean Journal of Agricultural Science
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• v.37 no.1
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• pp.1-6
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• 2010

Allelopathic activity of rotation crop residues to common weeds and selectivity of crops were studied for developing an alternative weed control strategy in upland organic farming. All rotation crop residues with various ratios suppressed weed growth, but the growth of crop species stimulated a little when those were grown with the mixture of rotation crop residues except a few crop species. Among the rotation crop residues used in this study hairy vetch was the most effective, followed by Chinese milkvetch, barley and rye in suppression of weed growth. The 90:10 (crop:soil, v/v) treatments incorporation rate of crop residues such as hairy vetch and Chinese milkvetch suppressed completely the growth of all weed species tested in this study. The effect of crop residues on suppression of weed growth reduced to 90% when the incorporation rates decreased to 60% [60:40 (crop:soil, v/v). It was noticed that broadleaf weed species were more susceptible to rotation crop residues than grass weed species. In the influence of crop residues on the crop growth, no growth inhibition was found in red pepper, lettuce and perllia at any incorporation rates, but tomato, cucumber and corn were slightly inhibited in a few cases at their highest incorporation levels. This study demonstrated that rotation crop residues especially hairy vetch and Chinese milkvetch have high herbicidal effects against weeds without inhibiting the growth of crop species.

• Weed & Turfgrass Science
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• v.2 no.4
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• pp.358-361
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• 2013

This study was conducted to determine the weed control effect of false seedbed in organic rice paddy field. False seedbed is one of the preventative weed control method, especially effective in upland vegetable field. False seedbed frequency and methods were examined by varying the processing time in greenhouse and field condition in 2012 and 2013. In greenhouse experiment, shallow recultivation and harrow surface soil was effective to control weed up to 70%. Optimal processing time of false seedbed was when the weed was two or three leaf stages. Under field condition, one-time treatment of false seedbed was 61% of weed suppression rate and two-times of false seedbed treatment was 79% of weed suppression rate. Monochoria vaginalis was still troublesome weed after false seedbed treatment, but the occurrence of Echinochloa oryzoides was decreased after false seedbed treament. Results indicated that false seedbed treatment was very effective to lower early weed occurrence in rice paddy field especially Echinochloa spp. Weed control efficiency of shallow recultivation by weeder hollow and rotary tillage by tractor were 68%, 13% respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.4
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• pp.581-590
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• 2011

Organic farming is rapidly expanding worldwide. Crop growth in organic systems greatly depends on the functions performed by soil microbes, and nutrient supply weed suppression by green manure crops input. Four red-pepper production systems were compared: 1) bare ground (conventional system); 2) hairy vetch monoculture; 3) rye monoculture; and 4) hairy vetch-rye mixture. Soil inorganic N reached the peak at 30 DAI and hairy vetch monoculture was the highest ($192mg\;kg^{-1}$) and soil total carbon was fluctuated sporadically during the experiment. Carbohydrate and phenolic compounds in soil kept significantly higher in green manure crops systems from 10 DBI to 30 DAI, however the level was the maximum at 10 DBI (carbohydrate) and 30 DAI (phenolic comounds). Incorporation of green manure crops residue enhanced soil microbial biomass C and N throughout the growing season except that MBN in rye was reduced after incorporation. Green manure crops systems suppressed weed occurrence and, in particular, it was prominent in rye monoculture. Mineral elements composition and production in red-pepper fruits were markedly decreased in green manure crops systems although hairy vetch monoculture has come close to bare ground (NPK-applied). Therefore, it was suggested that higher biomass production should be performed not only to improve soil quality and suppress weeds but to yield suitable red-pepper fruits in green manure crops-based organic farming.

• The Plant Pathology Journal
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• v.22 no.1
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• pp.90-93
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• 2006

Innate defence mechanism in plants can be triggered and enhanced by certain agents, referred as inducers against broad range of pathogens. In the present study, Dravya (a sea weed extract) was highly compatible with commonly available synthetic fungicides, Bavistin and Dithane M-45. Incidence of Alternaria padwickii and Bipolaris oryzae was also reduced to a greater extent in the paddy seed samples in Dravya treatment. Dravya also enhanced the seed germination and seedling vigour. Seedlings of treated samples also showed enhanced activity of peroxidase upon challenge inoculation with Alternaria padwickii. The enzyme activity was two fold high after the inoculation of pathogen. The suppression in disease incidence in growing plants indicated the promising effect of Dravya and Dithane M-45 under green-house condition.

• Weed & Turfgrass Science
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• v.3 no.4
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• pp.318-322
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• 2014

The effects of cover crops on weed suppression were evaluated in this study. Weed suppressing effects of hairy vetch cover crops were evaluated in summer grain fields. Cover crops were sown at the sowing rate of $60kg\;ha^{-1}$ on Oct. 2012 and Feb. 2013 without basal fertilization. Three weeks old sorghum seedlings were transplanted after minimum tillage on June 2013. Hairy vetch cover crop treatment significantly reduced weed biomass in the transplanted sorghum. By smothering, the cover crops reduced weed biomass to economic level in sorghum. Besides the weed suppression, hairy vetch cover crop resulted in green manure effect on crop growth. Hairy vetch treatment showed beneficial effects on sorghum growth. Reduction of weeds caused by use of strip-tillage machine and polyethylene film mulching was 71% and 88%, respectively. At harvest, yield of sorghum was greater in order of polyethylene film mulching > hairy vetch cover crop > control in transplanted fields.