• Korean Journal of Weed Science
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• v.4 no.1
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• pp.11-18
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• 1984

The effect of transplanting method of rice seedlings on weed occurrence was investigated at the Yeongnam Crop Experiment Station in 1983. Rice was transplanted by hand and machine and eleven common herbicides were applied. The greatest weeds were harvested from the plot that rice was not transplanted and more weeds encountered at machine transplanted plot than hand transplanted plot. The degree of weed suppression by rice plant itself was 50% for machine transplatning and 55% for hand transplanting, respectively. Simpson index and community dominance of weed species were the highest in hand transplanting and followed by machine transplanting and no rice plot in order. Rice grain yield was exponentially correlated with the amounts of weed occurrence and more yield loss exhibited at machine transplanting than hand transplanting in the same amount of weeds. In the herbicidal activity, most of herbicides performed better at hand transplanting than machine transplanting while the degree of difference between transplanting methods varied depend on herbicide used.

• Weed & Turfgrass Science
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• v.4 no.1
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• pp.44-48
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• 2015

This study was conducted to evaluate the efficacy of weed control and phytotoxicity of oxyfluorfen using a transgenic rice line (CPPO06 event) resistant to protoporphyrinogen oxidase (Protox) inhibiting herbicides in the direct-seeding flooded rice. Five annual weeds including Echinochloa oryzoides and two perennial weeds were occurred in the test field. Oxyfluorfen at 120 g a.i. $ha^{-1}$ in the application timing of two days before sowing and 0 and five days after sowing showed more than 90% weed control value except for Juglans mandshurica. Total weed control value was more than 95% in any application timing indicating a highly effective herbicide in the direct-seeding flooded rice. When compared with untreated control, no visual injuries were detected at single and double dosage of oxyfluorfen. The agronomic characteristics and yield components of CPPO06 event was reasonable in any time of application in this study. Based on these data, oxyfluorfen application before and after sowing can be applied to provide effective weed management in the direct-seeding flooded field.

• Korean Journal of Weed Science
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• v.18 no.2
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• pp.116-121
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• 1998

Field experiment were carried out to elucidate the changes of weed occurrence according to the sowing time and to establish the efficient weed control system in dry seeded rice cultivation. E crus-galli and D. sanguinalis are tow major weeds at the earlier sowings, but C. difformis was dominating at the later sowing. In the case of E. crus-galli, there was a tendency of gaining its dominance values as the rice growth stage advances. The later the sowing time was, the more weeds occurred at the early rice growth stages: However, when measured at heading, total dry weight was greater at the earlier sowings. Yield loss due to weeds were also greater at the earlier sowings. Community diversity of weeds was greater at the later sowings, while specific weed was gradually dominating as rice growth stage advances, regardless of sowing time. When herbicides were applied before 15 DAS, weeds were effectively controlled only upto 35 DAS. So systemic herbicide application, one on 0 to 10 DAS and the other on just after flooding, appeared to be recommendable in direct seeded rice cultivation.

• Korean Journal of Weed Science
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• v.15 no.4
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• pp.254-261
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• 1995

The nationwide weed survey was conducted in lowland rice fields over whole country of Korea in 1992 in order to determine a change of weed community and to identify a major dominant weed species and/or problem weed. Based on morphological characteristics of weeds, population ratio of broad leaf weed was 42.6%, grasses weed-9.0%, sedges-33.4% and others were 15.0%. Annual weed was 33.4% while perennial weed was 66.6% in terms of life cycle of weeds. Meanwhile, there was different weed occurrence as affected by planting method of the rice plant. In hand transplanted paddy fields predominant weed species was Sagittaria trifolia L., Monochoria vaginalis Presl., and Aneilema japonica Kunth. In machine transplanted rice fields of infant and young rice seedling Eleocharis kuroguwai Ohwi. and S. trifolia L. were more predominant. There was high occurrence of M. vaginalis, Echinochloa crus-galli L., and Leesia japonica Makino in water seeding while E. crus-galli and Cyperus serotinus Rottb. were predominant weed species in dry seeded rice. Monoculture of the rice plant would cause to high occurrence of E. kuroguwai, S. trifolia, M. vaginalis, E. crus-galli, and Sagittaria pygmaea Miq and there was higher population of S. trifolia, S. pygmaea, M. vaginalis, E crus-galli, and E. kuroguwai in double cropping system based on rice culture. In particular, there was high different weed occurrence under different transplanting times. E. kuroguwai, S. trifolia, S. pygmaea, M. vaginalis, and C. serotinus were higher population at the transplanting of 25 May and S. trifolia, E crus-galli, C. serotinus, and M. vaginalis at 10 June and S. pygmaea, E. kuroguwai, M. vaginalis, S. trifolia, and E. crusgalli at 25 June in Korea, respectively. Autumn tillage in terms of tillage time would cause more predominant weed species such as S. trifolia, E. kuroguwai, M. vaginalis, and S. pygmaea while spring tillage was higher population of E. kuroguwai, S. trifolia, E. crusgalli, M. vaginalis, and S. pygmaea. In plain area of paddy field there was higher occurrence of E. kuroguwai, S. trifolia, M. vaginalis, E. crus-galli, and S. pygmaea and in mid-mountainous area S. trifolia, E. kuroguwai, M. vaginalis, E. crus-galli, and Ludwigia prostrate Roxb. while in mountainous area S. trifolia, M. vaginalis, Potamogeton distinctus Ben., E. kuroguwai, and E. crus-galli were. In 1992 the most ten predominant weed species at the rice field of Korea based on summed dominant ratio(SDR) were E. kuroguwai > S. trifolia > E. crus-galli > M. vaginalis > S. pygmaea > C. serotinus > L. prostrate > P. distinctus > A. japonica > Scirpus juncoides Roxb.

• Korean Journal of Weed Science
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• v.5 no.2
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• pp.137-142
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• 1985

This experiment was conducted to know the difference in weed population in the five cropping patterns kept same for six years from 1976 such as ricebarley, potato-rice, pea-rice, rice-rye, and rice-fallow. More and many weeds were growing in single cropping field than double cropping field. Dominant weed species in pea-rice and potato-rice cropping patterns were M. vaginalis and S. hotarui, M. vaginalis and P. distinctus. Coefficient of similarity of the cropping patterns between pea-rice and potato-rice appeared higher than single cropping system. However, pea-rice and rice-fallow cropping patterns showed low coefficient of similarity.

• Korean Journal of Weed Science
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• v.3 no.1
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• pp.1-13
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• 1983

• Korean Journal of Weed Science
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• v.2 no.2
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• pp.175-187
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• 1982

• Journal of Internet of Things and Convergence
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• v.6 no.1
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• pp.83-95
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• 2020

Being a dense and complex task of precisely detecting the weeds in practical crop field environment, previous approaches lack in terms of speed of processing image frames with accuracy. Although much of the attention has been given to classify the plants diseases but detecting crop weed issue remained in limelight. Previous approaches report to use fast algorithms but inference time is not even closer to real time, making them impractical solutions to be used in uncontrolled conditions. Therefore, we propose a detection model for the complex rice weed detection task. Experimental results show that inference time in our approach is reduced with a significant margin in weed detection task, making it practically deployable application in real conditions. The samples are collected at two different growth stages of rice and annotated manually

• Korean Journal of Weed Science
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• v.30 no.3
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• pp.282-290
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• 2010

The objective of this research was to discover the best method for weed management in environment-friendly rice paddy fields through the study on the effect of weed control and injury levels of rice plants as affected by size, input time, and input amount of golden apple snail (GAS). The efficacy of weed control as affected by GAS when applied at 5, 10, and 15 days after transplanting (DAT) was 98, 89, and 58%, respectively. The efficacy of weed control had declined as late the input time of GAS. On the other hand, the efficacy of weed control as affected by rice bran followed by GAS treatment was higher than by GAS treatment alone. Weed species such as Persicaria hydropiper, Echinochloa crus-galli, Scirpus juncoides, and Monochoria vaginalis were not completely controlled by GAS when applied late. Input amount and time of adult GAS (70 days after hatching) for effective weed control were 3 kg $10a^{-1}$ at 5 DAT, 6-7 kg $10a^{-1}$ at 10 DAT, and 7 kg $10a^{-1}$ at 15 DAT. Input time and amount of young GAS (35 days after hatching) for effective weed control were 0 day after harrow (DAH) and 1 kg $10a^{-1}$, respectively. The young GAS when applied 0 DAH at 1 kg $10a^{-1}$ provided 100% control of P. hydropiper, E. crus-galli, S. juncoides, M. vaginalis, Ludwigia prostrata, Eleocharis kuroguwai, Sagittaria trifolia and Cyperus difformis. The rice foliar injury caused by adult (3 kg $10a^{-1}$) and young (1 kg $10a^{-1}$) GAS were 5-7% and 1% respectively. There was no significant difference in rice injury by size and input amount of GAS on plant height and number of tiller. These data indicate that the young GAS when applied 1 kg $10a^{-1}$ at 0 day after harrow was the best method for weed management in environment-friendly rice paddy fields.

• Korean Journal of Weed Science
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• v.17 no.1
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• pp.80-93
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• 1997

Allelopathic compounds as naturally occurring herbicide have originally reported from local vegetation since B.C. 300. These compounds are known as secondary plant metabolites which released from plants into the environment often attract or repel, nourish or poison other organisms. In recent, many natural plant allelochemicals be used to attempt to biologically or ecologically control weed among worldwide weed scientists. Some allelochemicals have also used as fungicides, insecticides, and nematodicides, and were less than man-made agrochemicals to damage the global ecosystem. It makes efficient use of resources internal to the farm, relies on a minimum of purchased inputs. Some scientists selected for allelopathic activity when breeding weed-controlling cultivars of rice, sorghum, cucumber, surflower etc. Thus, this paper is focused on allelopathic compounds isolated from cultivated crop with the high potential of prospective herbicides. The most environmentally acceptable and sustainable approach to utilization of allelopathy for weed control is to develop plant cultivars with proven allelopathic characteristics. In rice accessions, there are 60 cultivars/lines which have known as allelopathic activity and some of these cultivars control weed more less 90% within certain radius of activity. These accessions are originated from 15 countries including Korea, Japan, USA, India, Philippines, Indonesia, Laos, Taiwan, Afghanistan, Mali, Pakistan, Colombia, Egypt, China, and Dom. Rep. From these cultivars, the most common allelopathic compounds identified in rice are p-Hydroxybenzoic, Vanillic, p-Coumaric, and Ferulic acids. In addition, allelopathic lines of the following crop have shown inhibition of weed growth : beet (Beta vulgaris), lupin(Lupinus spp.), com(Zea mays), Wheat(Triticum aestivum), oats(Avena spp.) peas(Pisum sativum), barley(Hordeum vulgare), rye(Secale cereale), and cucumber(Cucumis sativus). Thus, future allelopathy research must be designed its potentially phytotoxic propertices and the ecotoxic features of the allelochemicals from release to degradation ; its ecological sustainability, its allelopathic effect in early growth. stages, and selectivity properties in combination with chemical stages, and selectivity properties in combination with chemical concentrations. Also, research approach in allelopathy might be screened for highly allelopathic germplasm collection of crops, the idea being to ultimately transfer this agronomic character into improved cultivars by either conventional breeding or other genetic transfer techniques.