• Korean Journal of Weed Science
• /
• v.18 no.4
• /
• pp.341-347
• /
• 1998

This study was carried out to investigate the effect of U-Granule formulation of molinate(S-ethylhexaphdro-1H-azepine-1-carbothioate) mixtures in green house and paddy field, Five minutes were taken for U-Granule to spread out 7m in irrigated water of direct seeded on flooded paddy surface. The concentration of active ingredient of molinate in molinate U-Granule application was similar to molinate+simetryn U-Granule application. But weeding effect of molinate+simetryn U-Granule on Echinochlor crus-galli was 23% higher Than single application of molinate at 7m from application point. Bioefficacy of molinate+simetryn+imazosulfuron U-Granule on control of Echinochloa crus-galli was higher than that of molinzte+imazosulfuton U-Granule, but those effect on Eleochairs kuroguwai was not significantly different. Only slight rice phytotoxicity was observed at 5m and 2m from application point of U-Granule molinate+simetryn+imazosulfuron and molinate+imazosulfuron, respectively. So it is concluded that there is little phytotoxicity problem in practical application of U-Granule of molinate mixtures.

• Korean Journal of Weed Science
• /
• v.12 no.3
• /
• pp.223-229
• /
• 1992

Very recently, the cultural pattern of paddy rice in Korea was transitted in a short period, and resulted as earlier in season and more in fertillizer application among others. Specially the weed emergence in paddy fields was drastically increased as affected by change of cultural pattern into early planting and into direct seeding methods. Of course, the direct-seeding in row seeding induced more weeds than in broad-cast direct -seeding. By maintaining the water level with saturation of the paddy surface induced more weeds, relatively more annual weeds than by deep in water level, respectively. Relatively more annuals in number of species and in emerged quantity comparing with perennials was caused by the shifting of cultural methods from transplanting to direct seeding. The severe weed competition damages were mainly resulted due to the shading by taller plant heights of weeds than crop during the whole growing seasons. Conclusively, accepting of direct seeding methods in paddy rice culture in Korea, the present bases for weed control methods ought to be naturally and effectively improved to meet the newly made weed problems.

• Korean Journal of Soil Science and Fertilizer
• /
• v.40 no.4
• /
• pp.255-261
• /
• 2007

Soil aggregates, resulting from physico-chemical and biological interactions, are important to understand carbon dynamics and material transport in soils. The objective of this study is to investigate stable macro-aggregate (> 0.25mm diameter) in wet sieving (SM) and their relation to soil properties in 15 sites. The clay contents of soils were ranged from 1% to 33%, and their land uses included bare and cultivated lands of annual upland crops, orchard, and grass. Undisturbed 3 inch cores with five replicates were sampled at topsoil (i.e., 0- to 10-cm depth), for analyzing SM and physico-chemical properties, after in situ measurement of air permeability. SM of sandy soils, with clay content less than 2%, was observed as 0%. Except the sandy soils, SM of soils mainly depended on land uses, showing 27%~35% in soils with annual plants such as vegetable and corn, 51% in orchard, and 75% in grass. This sequence of SM is probably due to the different strength of soil disturbance like tillage with different land uses. SM had significant correlation with cation exchange capacity, organic matter content, sand, clay, silt, bulk density, and exchangeable potassium (K) and magnesium (Mg), whereas fluctuating properties with fertilization such as pH, EC, and water soluble phosphorus weren't significantly correlated to the SM. Particularly, exchangeable calcium (Ca) had significant relation with SM, only except soils with oversaturating Ca. This study, therefore, suggested that SM could perceive different land uses and the change of soil properties in soils, necessarily considering soil textures and Ca over-saturation.

• Korean Journal of Weed Science
• /
• v.10 no.3
• /
• pp.202-206
• /
• 1990

Field experiment was conducted to develop a model of controlled release of oxyfluorfen by using various split applications. Rice and some weed species was included in this study. The models of split applications were 10-10-0. 10-10-10. 20-20-0, 20-10-10. 20-20-20, 0-40-0, and 0-0-0g/Ha at 3days before transplanting, and 11 days after transplanting, respectively. Rice injury appeared dispeared at 20 g/Ha of oxyfluorfen on low leaf sheath but disappeared at few days. The injury was reduced by split application even at the same rate of application. However, no injury was siginificant at 30 days after transplanting. Barnyardgrass, Monochoria, and arrowhead were most susceptible to oxyfluorfen, but bulruch and most perennial weeds recovered after temporary growth inhibition. Therefore, to develop oxyflourfen for use in rice transplanting of adult rice seedling, split application with reduced rates, and development of expected to be tank-mixed or premixed with other perennial herbicides to obtain droad spectrum of weeds.

• Weed & Turfgrass Science
• /
• v.3 no.2
• /
• pp.78-85
• /
• 2014

The survey of weed occurrence was conducted to identify dominant weed species in the paddy field. Total 346 sites of the 12 regions in Chungbuk Province in Korea were investigated in July, 2013. Weed flora was composed of 43 species belonged to 15 families. The compositions of major plant families, Cyperaces, Poaceae, Pontederiaceae and Asteraceae, were 21.5, 17.4, 15.5 and 12.7%, respectively. Based on life cycle, weed species was grouped into annuals of 71.3 and perennials of 28.1%. The most dominant weed species in paddy fields of Chungbuk Province were Monochoria vaginalis (14.5%), followed by Scirpus juncoides (10.5%), Echinochloa oryzoides (9.3%), Eleocharis kuroguwai (7.0%), Aeschynomene indica (6.2%) et al. The similarity of paddy weeds in 12 regions observed through TWINSPAN analysis was distinguished by Persicaria longiseta, Aneilema keisak, Persicaria thunbergii, Fimbristylis millacea, Blyxa japonica, Digitaria ciliaris, Potamogeton distinctus, Cyperus nipponicus. This information could be useful for estimation of future weed occurrence and establishment of weed control methods in chungbuk province in Korea.

• Korean Journal of Weed Science
• /
• v.3 no.2
• /
• pp.120-128
• /
• 1983

The nationwide survey of weed population covering 1,800 wheat and barley fields in 60 Cities and Guns all around Korea was conducted in December of 1982 and March-April of 1983. In this survey result, two species of gresses and 35 species of broadleaves were identified, and among them 36 and 29 species were found in the wheat and barley fields of upland and paddy, respectively. In the scope of weed life cycle, biennials were more dominant than perennials and annuals in these fields. The most dominant weed species in upland fields were Stellaria media, Cyrillus and Alopecurus aequalis Sobol var. amurensis Ohwi while those in paddy fields were Stellaria alsine Grimm. var. undulata Ohwi and Alopecurus aequalis Sobol var. amurensis Ohwi. In addition, the more weeds were observed in the conventional row seeding method than in other seeding methods including drill seeding and also in no-tillage than in tillage method. In the other hand, the successive use of herbicide for several years greatly influenced the pattern of weed occurrence; broadleaved weeds increased and grasses decreased with the successive use of herbicides.

• Weed & Turfgrass Science
• /
• v.4 no.3
• /
• pp.209-218
• /
• 2015

This study was conducted to investigate the weed occurrence and distribution on the upland crop fields (garlic, barley, potato, maize, red pepper, soybean and Chinese cabbage) at 795 sites in Chungbuk province of Korea from Apr. to Oct. in 2014. From the result of this survey, 188 weed species in 42 families were identified and classified to 96 annuals, 40 biennials and 52 perennials. Based on the occurrence ratio, the most dominant weed species in Chungbuk province upland crop fields were higher in the order of Portulaca oleracea (8.14%), Digitaria ciliaris (6.72%), Echinochloa crus-galli (6.55%), Rorippa palustris (6.00%) and Chenopodium album (5.89%). The composition of major occurred weed families, Compositae, Poaceae, Polygonaceae and Cruciferae were 19, 10, 7 and 6%, respectively. In the winter upland crop fields, the dominant weeds were in the order of Capsella bursa-pastoris (12.36%), Alopecurus aequalis (11.05%) and Stellaria alsine (8.42%). In the summer upland crop fields, the dominant weeds were in the order of Portulaca oleracea (8.58%), Digitaria ciliaris (7.18%) and Rorippa palustris (6.28%). Fiftythree exotic weed species were identified. The results of this study could be useful information for estimation of future weed occurrence, weed population dynamics and establishment of weed control methods on the upland crop fields in Chungbuk province of Korea.

• Korean Journal of Environmental Biology
• /
• v.37 no.4
• /
• pp.447-466
• /
• 2019

The orchard flora where perennial fruit trees are grown may be different than in arable fields where annual crops are grown. The study focused on the floristic composition and characteristics of orchards in South Korea. The flora surveys were conducted in 36 areas in nine provinces at two times (May-June and August-September) in 2014. The results showed that the vascular orchard plants in South Korea included 466 taxa, which contained 91 families, 278 genera, 420 species, two subspecies, 39 varieties, four forms, and one hybrid. Among the 91 families, Compositae was the most diverse in species (66 taxa), followed by Gramineae (51 taxa), Leguminosae (28 taxa), Cyperaceae (18 taxa), Polygonaceae (17 taxa), Cruciferae (16 taxa), and Labiatae (14 taxa). Based on the occurrence frequency of each species, Digitaria ciliaris (Retz.) Koel. (100%) was the highest, followed by Acalypha australis L. (94.4%), Commelina communis L. (94.4%), Persicaria longiseta(Bruijn) Kitag.(91.7), Capsella bursa-pastoris(L.) L. W. Medicus(91.7%), Erigeron annuus (L.) Pers. (91.7%), Mazus pumilus (Burm. f.) Steenis (86.1%), Artemisia princeps Pamp. (86.1%), Cyperus microiria Steud. (86.1%), Stellaria aquatica (L.) Scop. (83.3%), Stellaria media(L.) Vill.(83.3%), and Echinochloa crus-galli (L.) P. Beauv.(83.3%). The biological type of orchards in South Korea was determined to be Th-₅-D₄-e type. Rare plants were found six taxa: Cinnamomum camphora (L.) J. Presl, Aristolochia contorta Bunge, Melothria japonica (Thunb.) Maxim., Ardisia crenata Sims, Gnaphalium hypoleucum DC., and Aster koraiensis Nakai. Eighty-five taxa contained naturalized plants composed of 23 families, 58 genera, 80 species, four varieties, and one form. The urbanization and naturalization indices were 26.3% and 18.2%, respectively.

• Korean Journal of Plant Resources
• /
• v.19 no.5
• /
• pp.640-648
• /
• 2006

The distribution and status of naturalized plants in Jeju Island were investigated in this study. As results, the naturalized plants in Jeju Island were total of 254 taxa including 47 families, 161 genera, 248 species and 6 varieties. By the growth habits, annuals held the most percentage including 107 taxa (42.13%). Seventy nine taxa (31.1%) were appeared to have erect type in growth forms and 203 taxa (79.9%) are non-clonal growth form in disseminule forms by radicoid. The most of dormancy form in life form were therophytes as 150 taxa (59%), and following as 53 taxa (20.9%) for hemicryptophytes, and 26 taxa(10.2%) for geophytes. Among the naturalized plants, 115 taxa (36.7%) were originated from Europe, 69 taxa (22%) from Asia and 59 taxa (18.8%) from North America. Twenty eight percent of them were introduced as feeds or mixed seeds of imported cereals.

• Korean Journal of Weed Science
• /
• v.6 no.2
• /
• pp.134-145
• /
• 1986

The experiment was crried out to evaluated the herbicidal properties of bensulfuron methyl [methyl 2-[[[[[(4, 6-dimethoxy pyrimidine-2yl) amino] carbonyl] amino] sulfonyl] methyl] benzoate]. No phytotoxicity was observed when bensulfuron methyl was applied at 3 and 6 g a.i./ 10a while the application rate 12 g a.i./10a slightly retared the growth of rice. The phytotoxicity decreased as the application time was delayed. The effect of application rate, leaching grade, transplanting depth, soil type and temperature on crop injury was little. Japonica variety (Dong-Jin) was more sensitive to bensulfuron methyl than indica X japonica variety (Sam-Kang). Bensulfuron methyl controlled effectively perennial weeds such as Sagittaria pygmaea Miq., Potamogeton diatinctus A. Benn., Cyperus serotinus Rottb., Sagittaria trifolia L., Eleocharis kuroguwai Ohwi. including most annual weeds except Echinochloa crus galli P. Beauv. The effect slightly decreased with lowering the temperature increasing the leaching grade. Application time and soil type employed did not affect the weeding effect.