• Korean Journal of Environmental Agriculture
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• v.15 no.1
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• pp.86-90
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• 1996

This study was to provide the basic information for the development of thermal weeder which uses LPG as fuel. Weed seeds of Digitaria sanguinalis S. and Portulaca oleracea L. mainly developed in fram and forestry nurseries were used as experimental samples. At different irradiation temperature(60, 80, 100, 150, $200^{\circ}C$), the dffects of weed seed species(digitalis, purslane), condition of seed(dry, soaked), and irradiation time(2, 5, 10, 20, 30, 60, 180, 300 sec) on seed viability were investigated was investigated by examining interaction and main effect of experimental factors. The results showed that viability of weed seed was significantly affected by all irradiation temperature tested. Irradiation time significantly affected on viability of weed seed on all levels of irradiation temperature. also, there were interactions between condition of weed seed and irradiation time on seed viability at each irradiation temperature.

• Korean Journal of Weed Science
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• v.11 no.3
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• pp.219-223
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• 1991

Effects of media and low temperature on germination of weeds were examined to get basic information for establishing weed control methods. Soil and agar(0.4%) was good media for germination of weeds at laboratory. Germination was improved by placing weed seeds at 5$^{\circ}C$ low temperature for 10-20 days. Germination was improved by storing weed seeds in water absorbed gauge and in vinylbag at 5$^{\circ}C$ low temperature for 30-40 days. Germination was increased by burial of weed seeds at 10cm of soil depth for 30-60 days.

• Korean Journal of Plant Resources
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• v.10 no.2
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• pp.169-174
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• 1997

This study was conducted to obtain basic information needed to develop the effective weed control method by using thermal weeder which uses LPG as fuel. For survey of weed distribution in herb field, weed species were investigated at two kinds of herb field of Codonopsis lanveolata and Aster scaber located in Hoengseongkun and Hwacheonkun, Kangwondo. In Codonopsis lanveolata field, Digitaria sanguinalis and Persicaria viridis L were dominated. In Aster scaber field, Digitaria sanguinalis and Erigeron canadensis were dominated. In general, Grasses weeds in herb were more dominated than other broadleaf and Cyperaceae weeds. The treatments of $H_2SO_4$ in weed seeds were more effective for germination of several weeds, compared with that nontreated weed seeds. However, the rate of germination differed depending on weed species and tereatment time of $H_2SO_4. Also, viability of weed seeds was significantly affected by irradiation time and temperature. As the temterature and treatment time of irradiation increased, the rate of germination was decreased.

• Weed & Turfgrass Science
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• v.2 no.2
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• pp.170-175
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• 2013

Korea is carrying out weed quarantine by plant quarantine regulations including heat-treatment method to prevent the influx of exotic weeds. In order to confirm suitability for current heat-treatment criteria and find field-applicable methods which can completely devitalize quarantine weed seeds, the conditions for heat-treatment with/without 40% relative humidity were studied with 9 species among quarantine weed seeds and one weed species similar to quarantine weed. Dry heat-treatments had been tested under various temperatures and time conditions. All seeds were dead at the conditions of $95^{\circ}C$ for 48 hours, $100^{\circ}C$ for 36 hours, $110^{\circ}C$ for 24 hours, $121^{\circ}C$ for 4 hours and $130^{\circ}C$ for 30 minutes. Heat-treatments at 40% relative humidity resulted in complete seed death at the conditions of $85^{\circ}C$ for 36 hours and $90^{\circ}C$ for 16 hours. The above results show that current heat-treatment criteria are not suitable for several quarantine weeds and these conditions could be applied as a quarantine method to prevent the influx of quarantine weeds along with agricultural imports. More specific conditions for heat tolerant species such as Picris echioides and heat susceptible species such as Cuscuta spp. are necessary and will improve plant quarantine process in devitalizing quarantine weed seeds with different heat tolerances.

• Weed & Turfgrass Science
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• v.1 no.4
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• pp.1-5
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• 2012

A simple monitoring method was designed to evaluate seed bank in a upper soil (0 to 30 cm depth), which was observed for the pattern of vertical distribution of weed in the soil under tillage or no-tillage condition. The field experiment was established at an organic corn field located in Hwacheon in Kangwon-do from 2010 to 2011. Undistributed linear soil samples were taken using non-destructive soil sampler from 0 to 30 cm depth at the tillage or no-tillage soils. Weed seed distribution in the linear soil samples was estimated by counting the number of weed germinated according to the soil depth. Under tillage condition, the weed seeds were more evenly distributed from 0 to 30 cm depth, with being 75% of weed seeds located in 0 to 15 cm depth compared to the no-tillage condition. Soil samples taken by no-tillage condition had 85% of weed seeds within 15 cm of soil depth, with being 93% of weed seeds from 0 to 20 cm depth. The number of weeds or the number of weed species were three times higher for tillage soil compared to no-tillage soil, and the major dominant weed species were observed for annual plants, such as Echinochloa crus-gall, Mollugo pentaphylla, and Digitaria ciliaris.

• Korean Journal of Weed Science
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• v.17 no.3
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• pp.269-280
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• 1997

Collated data from the 1995-1996 field surveys of weed seeds buried in the plough layer of peat soil in Selangor district were analysed to assess species-dominance and spatial pattern of distribution of weed seeds based on selected quantitative indices and index of dispersion. Forty five species within 14 families were recorded of which 24 were broadleaves, 12 grasses and 9 sedges. They comprised ca. 53.2, 31.2 and 15.6%, respectively based on total population counts. Total seed population was ca. $8.14{\times}10^7$ seeds/ha within the fast 25cm soil depth. Wide variabilities in population counts were registered among species ranging from < $7.0{\times}10^4$ seeds/ha for Amaranthus gracilis to ca. $5.64{\times}10^6$ seeds/ha for Heteropogon contortus. Seeds of Cleome rutidesperma was the most abundant(ca. $2.347{\times}10^7$ seeds/ha). Difference in seed population counts may be attributed to inherent variation in fecundity, population fluxes, their spatial distribution patterns and the agronomic practices prevailing in the areas of survey. The profile distribution of soil seed banks was skewed within the first 0 - 10cm depth, comprising ca. 69% of the total seed counts. Seed counts in the 10 - 15, 15 - 20 and 20 - 25cm soil profiles were in the order of 17.9, 8.6 and 4.0% of the total populations, respectively. Weed seeds of all species displayed different degree of aggregated pattern of distribution with variance-to-mean ratios of > 1 and Lloyd's mean crowding($m^*$) values from 1.244 for Cyperus iria, Phyllanthus debilis, Phyllanthus urinaria, Scirpus grosses and urinaria lagopodiodes to 9607.7 for Cleome rutidosperma. Lloyd's patch indices(Ip) ranging from 5.1 for Aeschynomene indica to 188.5 for Bracharia reptans were registered. Differences in the VMR, $m^*$ and Ip values among species suggested inter-alia inherent variabilities in their disposal capacity from seed source and different agronomic practices prevailing in the areas surveyed.

• Agrochemical news magazine
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• v.16 no.6 s.129
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• pp.18-23
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• 1995

• Life and Agrochemicals
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• s.249
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• pp.44-45
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• 2009

도깨비가지는 종자 뿐만 아니라 뿌리의 번식력이 왕성하여 방제가 어려운 문제 잡초이다. 종자발아를 억제시키는 토양처리형 제초제와 뿌리까지 방제할 수 있는 경엽처리형 제초제로 방제한다.

• Korean Journal of Environmental Agriculture
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• v.15 no.1
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• pp.91-104
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• 1996

The viability loss or death of weed seeds buried in soil can be induced by infrared irradiation which has good penetration in moist soil. By using this principle of pre-emergence soil-treatment, the study was carried out to obtain basic information needed to develop the effective weed control method for the production of less polluted agricultural products. An apparatus for irradiating infrared was constructed by using ceramic material with high emissivity. The LPG was used as fuel for producing infrared by heating ceramic material. The soil heated in this study was loam with four levels of moisture contents (0.6, 5.7, 10.7, 15.1 % wb). The temperature distribution was measured at various soil depths when soil with different moisture content was irradiated with infrared for three different times (30, 60, 90 sec). The soil depths with duration time of minimum 3 minutes over $80^{\circ}C$, temperature inducing viability loss of weed seeds, were investigated. When the moisture content of soil was 0.6 and 5.7 % wb, the soil depths which can induce viability loss of weed seeds was greatly increased with increasing irradiation time. However, any depths of soil tested in this study was not reached to the temperature of $80^{\circ}C$ when 30 seconds of irradiation time was applied on soil with moisture content of 10.7 or 15.1 % wb. Generally, the soil depth needed for viability loss of weed seeds was decreased with increasing moisture content of soil. Also, longer irradiation time was required to induce viability loss of weed seeds with increasing moisture content of soil.

• Journal of Practical Agriculture & Fisheries Research
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• v.18 no.1
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• pp.93-100
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• 2016

This research was conducted to determine a pre-germinated herbicides with iron-coated seeds in water and wet hill seeded rice. Days of rice seedling emergence was the faster germination at the application of benzobicyclon > oxadiazon > thiobencarb > butachlor and the sealed iron-coated seeds with pre-germinated seeds> pre-germinated seeds> iron-coated seeds with pre-soaking. The seedling establishment was relatively high in untreated control and benzobicyclon among seed treatments by 63.7% and 75.7%. There was 100% seeds killed of pre-germinated seeds in terms of herbicide phytotoxicity and sealed iron-coated seeds with pre-germinated seeds in butachlor but benzobicyclon was of safe with 2% rice seeds killed. Infant rice seedling height was of 9.2-12.9cm in benzobicyclon and 11.9-16.3cm in untreated control and thus there was relatively normal development and growth at the initial rice seedling.