• Korean Journal of Weed Science
• /
• v.32 no.3
• /
• pp.273-279
• /
• 2012

This experiment was conducted to determine a potential effective biological weed control and/or rice young seedling injury by golden apple snail (Pomacea canaliculata) at wet hill seeded rice field. The rice seeds used were treated by iron-coating. The efficacy of weed control as affected by golden apple snail has been tested with twice applications of young golden apple snails of 12 kg (24,000 young snails, $0.5g{\pm}10%$ per young snail, 30~40 days after hatching) per ha at the same day after harrowing and applied with rate of 10 kg (20,000 young snails) per ha at 15days after seeding, respectively. The comparison of this experiment was of the conventional machine transplanted rice paddy field in terms of weed control and rice plant injury as a visual grade. The weed efficacy was of 100% similar with the conventional paddy field which was applied by systematic herbicides of pre-emergence and post-emergence chemical herbicides and there was 1~3% significant rice young seedling injury but no yield losses and grain quality due to the input of golden apple snail.

• The Korean Journal of Ecology
• /
• v.20 no.3
• /
• pp.191-200
• /
• 1997

The present study was undertaken to classify and describe the weed communities of the fields in Korea by methods of the ZM school of phytosociology. On the basis of the data obtained, the following vegetation units were recognized: A. summer weed community of rice field A-1. Oryzetea sativae: Sagittario-Monochorietum, A-2. Lemnetea minoris: Lemna paucicostata-Spirodela polyrrhiza community B. spring weed community of rice field B-1. Bidentetea tripartitae: Stellario-Ranunculetum cantoniensis C. summer weed community of arable land C-1. Chenopodietea Pinellio ternatae-Euphorbietum pseudochamaesyceslsynonym: Acalypho australis-Digirietum pectiniformis and Cephalonoploso segetti-Geranietum eriostemonii of North Korea in Dostal다 et al.(1990)] and Phyllantho urinariae-Lindernietum crustaceae D. weed community of fallow field D-1. Erigeron sumatrensis-Erigeron anmus community, D-2. Digitaria adscendens-Portulaca oleracea community, D-3. Chenopodium album community, and D-4. Erigeron canadensis-Erigeron annuus community. Generally compared to the Korean Peninsula, the weed communities in the fields of Cheju Island is much plentiful in their species composition.

• Korean Journal of Weed Science
• /
• v.16 no.4
• /
• pp.251-258
• /
• 1996

• Korean Journal of Weed Science
• /
• v.18 no.1
• /
• pp.1-11
• /
• 1998

This experiment was conducted to investigate weed infestation and to determine effective weed control methods in direct-seeded rice. Twenty two weed species occurred in dry- and water-seeded rice, which was mainly composed of annual weeds. Dominant weed species in dry-seeded rice were Cyperus difformis, Echinochloa crus-galli, Aneilema keisak and Digitaria sanguinalis in discending order. Dominant weed species in water-seeded lice were E. crus-galli, C. difformis, Monochoria vaginalis and Scirpus juncoides. E. crus-galli emerged at 7 days after sowing. In water-seeded rice, E. crus-galli emerged at 5 days after sowing, and M vaginalis, S. juncoides and C. difformis at 8~10 days after sowing. Mean days to emerge important weeds was 20 days in dry-seeded rice and 13 days in water-seeded rice. Leaf development of weeds was faster than that of rice in dry-seeded rice. In water-seeded rice, E eras-galli was more vigorous than rice, but leaf development of other weeds were slower than that of rice. Changes in number of weeds and dry weight oil weed species varied depending upon weed species in the direct-seeded rice. Dry weight of weeds were increased greatly from 30 days to 60 days after sowing in dry-seeded rice. Number of weeds tended to increase up to 40 days after sowing drastically, and then trend of the increase was dull thereafter. Dry weight and number of weeds increased up to 20~60 days after sowing in water-seeded rice. Most effective herbicide treatments was foliar application of cyhalofop/bentazon at 20 days after sowing followed by fenoxaprop/bentazon at 45 days after sowing in dry-seeded rice. All herbicide treatments except foliar applications were very effective to control weeds in water-seeded rice. Slight phytotoxicity was observed in foliar applied fenoxaprop/bentazon at 45 days after sowing in water-seeded rice, but it did not affect rice yield.

• Korean Journal of Weed Science
• /
• v.15 no.4
• /
• pp.278-288
• /
• 1995

Weed species occurred in dry- and water-seeded rice were 14 (2 grasses, 8 broadleaves, and 4 sedges) and 12 species (1 grasses, 7 broadleaves, and 4 sedges), respectively. Dominant weed species in dry-seeded rice were Lindernia procumbens, Cyperus difformis, Cardamine flexuosa, and Cyperus serotinus in discending order. The species in water-seeded rice were Cyperus difformis, Scirpus juncoides, and Lindernia procumbens. The number of weed species emerged in direct-seeded rice was determined at about 45 days after seeding, and dry weights of weeds were increased up to 75~90 days after seeding. Timing for great increase of plant height varied depending upon weed species. Regardless of weed number emerged, the most dominant weeds until late stage of growth were Cyperus difformis, Bidens frondosa, Digitaria ciliaris and Echinochloa crus-galli in dry- seeded rice, and Cyperus difformis, Echinochloa eras-galli and Scirpus juncoides in water-seeded rice.

• Korean Journal of Environmental Agriculture
• /
• v.42 no.1
• /
• pp.63-70
• /
• 2023

Golden apple snails (Pomacea canaliculat) (GAS) are widely used for weed control in rice cultivation. However, concerns on the ecological risk of invasive GAS species are increasing. This study aimed to evaluate the overall impacts of GAS on weed control, abundance of aquatic animals and insects, and rice yield, in comparison with that from other biocontrol agents such as loach (Misgurnus mizolepis) and catfish (Silurus asotus), which are alternatives for biological weed control in rice paddy cultivation. Field experiments included five treatments; control, herbicide, GAS, loach, and catfish. During the rice growth, weed appearance and biological abundance were monitored, and at harvest, the rice yield was determined. Weed control efficiency was the highest for GAS treatment (100%), followed by that for herbicide (95.8%), loach (57.5%), and catfish treatments (31.7%). Insect abundance was considerably decreased in GAS treatment due to heavy weed removal, which affects the habitat of aquatic animals and insects. The amount of rice yield (unit: kg 10 a^-1) was in the order of GAS (798.9) > loach (708.1) = herbicide (700.7) > catfish (629.4) > control (496.0). Therefore, considering the weed control efficiency, biological abudance, and rice yield, loach could be a potential alternative for biological weed control in organic rice farming. However, the activity of the biocontrol agents are susceptible to environmental conditions; therefore, further studies under different conditions are essential to confirm these findings.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.47 no.2
• /
• pp.80-84
• /
• 2002

In spite of simple and cheap cultivation method, water broadcast-seeded rice demonstrates uneven and unstable seedling establishment per unit land area and requires more herbicide and labor-input for weed control. Three experiments were conducted in a phytotron at 18$^{\circ}C$ to evaluate the adaptability of seed-mat mulching cultivation technologies in water seeded rice for the uniform seedling establishment and the inhibition of weed occurrence without herbicide application. Five different kinds of mat with different mesh sizes and fabric properties were tested. The emergence of rice was the highest in Lawn-mat treatment, being comparable with the control, in which seeds were sown without mat. The Lawn-mat also exhibited the lowest mat tension. Mat tension may influence the emergence of rice. And once it was soaked in water, it didn't maintain its original shape any more. The emergence rate of rice was the lowest in Safer-mat treatment. In Lawn-mat treatment, which was the most effective for rice emergence in the first study, the differences of emergence and seedling establishment of rice depending on the seeding position (upper, beneath, and between mats) treatments were negligible, while they were higher in dry seeds than in pre-germinated seeds treatment. The emergence as affected by the kinds of mat also showed the same trend when tested using barnyard grass. Depending on the kinds of mat, the inhibition effect of weeds was the greatest in Safer-mat and the poorest in Lawn-mat. These results strongly suggest the possibility that the uniform seedling establishment and weed management without chemical could be achieved simultaneously by seed-mat mulching through the combination of effective mat for the emergence of rice and another efficient mat for the inhibition of weed occurrence. This possibility was also tested in the field.

• Korean Journal of Weed Science
• /
• v.18 no.4
• /
• pp.281-285
• /
• 1998

This experiment was carried out to evaluate the effect of recycled paper mulch on weed occurrence and the growth and yield of rice in dry-seeded paddy field. Mulch papers with basis weight of 105, 110, 115g/$m^2$ were fabricated from recycled corrugate container. It took about 80 days after mulching for the mulch papers to reach 50% decomposition, showing no significant differences among types of mulch paper. Paper mulching was very effective in controlling the paddy weeds at early stage of rice growth, but the efficacy of weeds control decreased a little at late season. However the efficacy was still higher than the plot using herbicide. The paper mulch plot showed rice yield similar to the weed control plot using herbicide. It could be concluded that paper mulch can be used as an alternative for non-herbicidal weed control and ensure as high yield as the conventional weed control method using herbicide in dry-seeded rice field.

• Weed & Turfgrass Science
• /
• v.5 no.4
• /
• pp.191-195
• /
• 2016

Tefuryltrione is a new hydroxyphenylpyruvate dioxygenase (HPPD) inhibitor, which has been recently registered for the use for paddy rice, Korea. Dose-response studies were conducted to compare rice safety and weed control efficacy of tefuryltrione against Eleocharis kuroguwai. When rice and E. kuroguwai were applied at a range of doses of tefuryltrione, $GR_{90}$ values (the dose required to inhibit weed growth by 90%) of E. kuroguwai were $82.38-93.39g\;a.i.\;ha^{-1}$ in two independent experiments. The $GR_{10}$ values (the dose required to inhibit rice growth by 10%) of tefuryltrione for rice were $297.77-471.54g\;a.i.\;ha^{-1}$. As a result, the selectivity indices ($GR_{10}$ for $rice/GR_{90}$ for E. kuroguwai) of tefuryltrione were 3.19-5.72. Therefore, these results demonstrate that tefuryltrione has a relatively high selectivity between rice and E. kuroguwai with a high herbicidal activity against E. kuroguwai and a good rice safety.

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