• Korean Journal of Weed Science
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• v.31 no.3
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• pp.260-270
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• 2011

This study was carried out to examine the effect of rice bran, barley bran, burned rice bran, and burned barley bran on the growth and yield of Chinese chive (Allium tuberosum Rottler), taro (Colocasia esculenta), and weed control. When the above 4 brans were examined 13, 27, 41 and 57 days respectively after application, the plant height of Chinese chive applied with burned barley bran was significantly higher than non-treated control, whereas the other brans did not have any distinct effect on the plant height or population number of Chinese chive. However, when examined 57 days after the application of the above 4 brans, all the plants applied with brans showed more than twice the improvement in shoot fresh weight compared with non-treated control. A chemical analysis of soil 57 days after the application of the above 4 brans showed that the soils were richer in available phosphate and organic matter. Shoot fresh weight of Chinese chive at 2 weeks after cutting was significantly higher in barely bran treated plot than in non-treated plot. In the case of taro, only taro plots transplanted when 10 cm tall and applied with barley bran showed an improvement in growth increment of both the underground and above parts. However, when sowed seeds after the application of the 4 brans, the yield of taro was reduced by the brans. Thus this research indicates that the effect of brans is differ based on the amount of bran application as well as crops. The effect of weed control on Echinochloa crus-galli, Digitaria clliaris, Chenopodium album, and Solanum nigrum as affected by brans was very low in pot conditions. Weed efficacy of the brans was also very low in field conditions. Growth of Chinese cabbage and garland chrysanthemum was inhibited 63% and 37% by rice bran at $4,000kg\;ha^{-1}$, respectively, but other crops such as maize, squash, cucumber, and Chinese chive were inhibited by 0-20%. These results were similar to that of barley bran except for Chinese cabbage.

• The Korean Journal of Pesticide Science
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• v.4 no.3
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• pp.82-88
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• 2000

The objective of this study was to determine if wood vinegar of Quercus mongolica Fisch has herbicidal activity. Growth of plants, such as barnyard grass (Echinochloa crus-gulli P. Beauv), quackgrass (Agropyron smithii RYDB), canola (Brassica napus L.), velvetleaf (Abutilon avicennae), indian jointvetch (Aeschynomene indica), and common sorghum (Sorghum bicolor) grown on agar batch treated with 0.01% wood vinegar were similar to that of plant without wood vinegar. The growth of such plants, however, reduced at $0.1{\sim}1%$ concentrations, and inhibited totally at >5% concentration. In greenhouse study, soil-applied wood vinegar did not inhibit tile growth of canola, barnyard grass, large crabgrass, and Abutilon avicennae even at the highest concentration, 80L $80L^{-1}\;10a^{-1}$, while foliar-applied wood vinegar did inhibit the growth of plants at higher than 40L $80L^{-1}\;10a^{-1}$. Growth of canola, barnyard grass, large crabgrass, and Abutilon avicennae treated with wood vinegar (80L $80L^{-1}\;10a^{-1}$) was reduced by 71, 46, 24, and 47%, respectively. In field experiment conducted at Chunchon and Taebeck, biomass of weeds treated with wood vinegar at less than 40L $80L^{-1}\;10a^{-1}$ were close to that of weeds treated without wood vinegar, while biomass of weeds at 80L $80L^{-1}\;10a^{-1}$ was reduced by 34-36%, compared to that of control, at both sites. However, the herbicidal activity of wood vinegar was much lower than that of glyphosate. Results in this study show that wood vinegar of Quercus mongolica Fisch has herbicidal activity, although the herbicidal activity was lower than that of glyphosate, a commercial herbicide.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.3
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• pp.121-133
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• 2023

The purpose of this study was to improve weed management systems under varying carbon dioxide concentrations and temperatures by evaluating the growth of Acalypha australis and observing the efficacy of four foliar and four soil herbicides, as well as measuring phytotoxicity in soybean crops treated with these herbicides. In both growth chamber and greenhouse conditions, plant height and shoot fresh weight of Acalypha australis increased as temperature increased. The variable to maximum fluorescence ratio (Fv/Fm), relative electron transport rate (ETR), plant height, leaf area, and shoot fresh weight of Acalypha australis were higher at carbon dioxide concentrations of 800 ppm than at 400 ppm. The efficacy of a foliar herbicide, glufosinate, on Acalypha australis was lower at 30℃ than at 20℃ and 25℃ in the growth chamber condition and was also lower at 29℃ than at 21℃ and 25℃ in greenhouse conditions. In contrast, mecoprop efficacy on Acalypha australis was lower at 20℃ and 25℃ than at 30℃ in growth chamber conditions and lower at 21℃ and 25℃ than at 29℃ in greenhouse conditions. Glyphosate efficacy was lower at 21℃ than at 25℃ and 29℃ under greenhouse conditions. With soil herbicides, metolachlor and ethalfluraline, efficacies were higher at relatively high temperatures under both growth chamber and greenhouse conditions. However, in the case of linuron, the difference in efficacy was not observed under varying temperatures in both growth chamber and greenhouse conditions. When ¼ of the recommended glyphosate rates were applied to Acalypha australis, efficacy was lower under 800 ppm carbon dioxide concentrations than under 400 ppm. In contrast, when ¼ of the recommended rate of bentazone was applied to Acalypha australis, efficacy was higher under 800 ppm carbon dioxide concentrations than under 400 ppm. Despite application rates, glufosinate efficacy differed insignificantly under different carbon dioxide concentrations. When applied at ¼ of the recommended rate, the efficacy of ethalfuralin was higher under 800 ppm carbon dioxide concentrations than under 400 ppm. However, efficacies of other herbicides were not different despite varying carbon dioxide concentrations. Soybean phytotoxicity in crops treated with the recommended rate and twice the recommended rate of soil herbicides was not significantly different regardless of temperature and carbon dioxide concentrations. Overall, weed efficacy of some herbicides decreased in response to different temperatures and carbon dioxide concentrations. Therefore, new weed management methods are required to ensure high rates of weed control in conditions affected by climate change.

• Journal of Bio-Environment Control
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• v.4 no.1
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• pp.50-58
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• 1995

These studies were carried out to develop a system for non -destructive and continuous measurement of fresh weight and to analyse the growth response of leaf lettuce under the different nutrient solution and light condition with this system. The developed measurement system was consisted of four load cells and a microcomputer. The output from the system was highly positive correlation with the plant fresh weight above the surface of the hydroponic solution. The top fresh weight of plant could be measured within the error $\pm$ 1.0g in the range of 0 - 2000g. The top fresh weight of leaf lettuce increased 44 times at 18th day after transferring to the nutrient solution, and the maximum growth rate was observed at 13th day after transferring. The growth rate was 10.7- 29.6% per day during 18 days. Optimum concentration of the nutrient solution for the growth of lettuce was 1.4 - 2.2 mS/cm of EC level. When the light condition was changed from dark to light, the fresh weight was temporarily decreased, but the fresh weight increased under the opposite condition. Top fresh weight of leaf lettuce in the darkness normally increased within 12 hours after darkness treatment, and then slowly increased until 78 hours under continuous dark condition. After that times, the fresh weight began to decrease.

• Korean Journal of Weed Science
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• v.31 no.2
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• pp.119-133
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• 2011

Sulfonylurea (SU)-resistant weeds include seven annual weeds such as Monochoria vaginalis, Scirpus juncoides and Cyperus difformis, etc., and three perennial weeds of Scirpus planiculmis, Sagittaria pigmaea and Eleocharis acicularis as of 2010 since identification Monochoria korsakowii in the reclaimed rice field in 1998. The Echinochloa oryzoides resistant to acetyl CoA carboxylase (ACCase) and acetolactate synthase (ALS) inhibitors has been confirmed in wet-direct seeding rice field of the southern province, Korea in 2009. In the beginning of occurrence of SU-resistant weeds the M. vaginalis, S. juncoides and C. difformis were rapidly and individually spreaded in different fields, however, theses resistant weeds have been occurring simultaneously in the same filed as time goes by. The resistant biotype by weed species demonstrated about 10- to 1,000-fold resistance, base on $GR_{50}$ (50% growth reduction) values of the SU herbicides tested. And the resistant biotype of E. oryzoides to cyhalofop-butyl, pyriminobac-methyl, and penoxsulam was about 14, 8, and 11 times more resistant than the susceptible biotype base on $GR_{50}$ values. In history of paddy herbicides in Korea, the introduction of SU herbicides including besulfuron-metyl and pyrazosulfuron-ethyl that control many troublesome weeds at low use rates and provide excellent crop safety gave farmers and many workers for herbicide business refreshing jolt. The products and applied area of SU-included herbicides have been rapidly increased, and have accounted for about 69% and 96%, respectively, in Korea. The top ten herbicides by applied area were composed of all SU-included herbicides by 2003. The concentrated and successive treatment of ACCase and ALS inhibitors for control of barnyardgrass in direct-seeded rice led up to the resistance of E. oryzoides. Also, SU-herbicides like pyrazosulfuron-ethyl and imazosulfuron which are effective to barnyardgrass can be bound up with the resistance of E. oryzoides. The ALS activity isolated from the resistant biotype of M. korsakowii to SU-herbicides tested was less sensitive than that of susceptible biotype. The concentration of herbicide required for 50% inhibition of ALS activity ($I_{50}$) of the SU-resistant M. korsakowii was 14- to 76-fold higher as compared to the susceptible biotype. No differences were observed in the rates of [$^{14}C$]bensulfuron uptake and translocation. ALS genes from M. vaginalis resistant and susceptible biotypes against SU-herbicides revealed a single amino acid substitution of proline (CCT), at 197th position based on the M. korsakowii ALS sequence numbering, to serin (TCT) in conserved domain A of the gene. Carfentrazone-ethyl and pyrazolate were used mainly to control SU-resistant M. vaginalis by 2006, the early period, in Korea. However, the alternative herbicides such as benzobicyclone, to be possible to control simultaneously the several resistant weeds, have been developing and using broadly because the several resistant weeds have been occurring simultaneously in the same filed. The top ten herbicides by applied area in Korea have been occupied by products of 3-way mixture type including herbicides with alternative mode of action for the herbicide resistant weeds. Mefenacet, fentrazamide and cafenstrole had excellent controlling effects on the ACCase and ALS inhibitors resistant when they were applied within 2 leaf stage.

• Korean Journal of Weed Science
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• v.16 no.3
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• pp.237-244
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• 1996

Propanil [N-(3,4-dichlorophenyl) propanamide] which was applied at 4,200g ai/hapostemergence 7 days after seeding or transplanting, completely reduced the growth of shoot and root of barnyardgrass at 100% under dry condition while plant height, root length and shoot fresh weight of barnyardgrass at 63, 40 and 78%, respectively under water condition. On the other hand, the herbicide did not affect the growth of shoot and root of rice grown under water condition and transplanting condition, but reduced the plant height, root length and shoot fresh weight of broadcast rice on soil at 24, 18 and 28%, respectively, under dry condition. Microscopically, the epidermal cells of treated-barnyardgrasses under both conditions were severely constricted, chloroplasts in the cells of vascular bunble sheath were partially lacked, and mesophyll cells were often ruptured, whereas those of treated-rice were not affected. Histological observations showed that propanil reduced the thickness of leaf blade of barnyardgrass under both conditions at 36-48% due to mainly reduction and constriction of mesophyll cell, while it did not affect or even increased the thickness of leaves of rice under all conditions compared to control. These results indicate that broadcast rice on soil were more injured than drilled rice in soil under dry condition, however, in the other tested conditions ricer were not affected.

• Korean Journal of Weed Science
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• v.2 no.2
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• pp.75-113
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• 1982

Studies were carried out 1) to define the shape and size of sampling quadrat and its number of observations for weed experiments, 2) to characterize the growth and community of major summer weeds under upland condition and 3) to investigate the factors influencing competition between weeds and soybeans under weed-free and weedy conditions in early and late season cultures. No significant difference was noted among different shapes of quadrat (regular, rectangular, band, and circular) in the sampling efficiency of weeds. The results also suggested that the minimum size of quadrat was 0.25$m^2$ and the minimum number of replication was 2 times per plot. The major dominant weeds were about 10 species in the experimental field and the total number of weeds was in the range of 70 - 1,600 plants per $m^2$. Among the weeds Digitaria sanguinalis and Portulaca oleracea were the most dominant species. Growth amount and reproduction capability were also measured by weed species. Five different weed communities were identified in the field. The degree of dispersion by weed species and association among weeds were investigated. Intra-(within soybeans) and inter-specific (between soybeans and weeds) competition were studied in early and late season cultures of soybeans. The average yield of soybeans per plant was significantly decreased in both season cultures due to intra-specific competition as the planting density of soybeans increased, On the other hand, the average yield of soybeans per l0a was proportionally increased to the increase of planting density and the rate of its increase was more significant under weedy than weed-free condition. Most of the agronomic characteristics of soybeans were affected by weeds and its degree was greater in sparse planting than in dense planting and in early season than in late-season culture. Digitaria sanguinalis was the most competitive to soybeans in early season and both of Digitaria sanguinalis and Portulaca oleracea affected primarily the growth of soybeans in late season with about the same competitiveness. The occurrence of weeds was significantly decreased in early season and slightly decreased in late-season by dense planting of soybeans. The total growth amount of weeds was also considerably decreased by increase of soybean planting density both in early- and late-season cultures. The occurrence of Digitaria sanguinalis which was the most dominant in both seasons, and its growth amount was significantly decreased as the planting density of soybean was increased. On the other hand, the occurrence of Portulaca oleracea which was only dominant in late-season culture did not show significant response to the planting density of soybeans.

• Weed & Turfgrass Science
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• v.7 no.2
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• pp.111-119
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• 2018

This study was carried out to investigate the differences in germination and growth of Quamoclit coccinea Moench under various temperatures, seeding depths, and levels of shading and soil moisture for effective weed management. Seed dormancy of Q. coccinea Moench was over 1 year; best results were obtained when seeds were soaked in sulfuric acid for 15 minutes in order to break the dormancy. Germination rates of Q. coccinea Moench ranged from 69 to 73% at $25-35^{\circ}C$ and 26% at $15^{\circ}C$. The germination rates ranged from 70-84% at 2, 3, 5, 7, and 8 cm of seeding depths. In addition, the germination rates were 7% and 13% at 12 cm and 15 cm of seeding depths, respectively, and showed normal growth at the both seeding depths. Q. coccinea Moench showed a high germination rate regardless of shading levels, but shoot fresh weight varied depending on the level of shading as follows: 20%>no shading=shading 35%>shading 50%>shading 75%=shading 90%. Q. coccinea Moench did not germinate when soil had a saturation rate of either 30% or 100%. However, 60-83% of seeds germinated with optimal growth when soil had saturation rates of 60% and 80%.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.1
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• pp.20-27
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• 1996

Greenhouse experiment was carried out to investigate the specifics in growth, weed competition, and herbicide response of soybean(Glycine max) under foggy condition. Plant height and leaf stage of soybean under foggy condition were greatly increased through all growing stage comparing with non-foggy condition. At 100 days after seeding, plant height of soybean also was increased by 14％ while number of pods, number of grains per pod were reduced by 16, 24 and 23％, respectively comparing with non-foggy condition. On the other hand, plant height of soybean under foggy condition was reduced with increasing the duration of competition and this tendency was similar to non-foggy condition. Plant height was reduced by above 50-day competition. Number of pods per plant of soybean was reduced regardless of foggy condition. Among the herbicides treated, quizalofop caused slightly crop injury under foggy condition, but the other herbicides did not affect growth of soybean. Number of pods and 100-grain weight of soybean by treatment of herbicides were similar to that of the untreated control but those of soybean under foggy condition were significantly reduced. At 40 days after herbicide application, weeding efficacy (based on shoot fresh weight) of herbicides treated under foggy and non-foggy condition, released exellent data(above than 97％) in all regardless foggy condition.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.112-112
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• 2022

외래잡초인 애기수영(Rumex acetosella)는 생태계 교란종으로 생물다양성을 감소시키고, 우리나라 목초지에 우점하고 있어 큰 문제를 야기한다. 애기수영의 경우, 살초효과 및 제초활성물질인 chrysophanic acid와 catechd이 밝혀져 있지만, 톨페스큐(Festuca arundinacea)에 대한 살초 효과 연구는 미비하다. 이에 본 연구는 톨페스큐 종자에 대해 애기수영 MeOH 추출물을 처리한 Seed bioassay를 진행해 IC₅₀ 값을 구하고, 톨페스큐에 애기수영 MeOH 추출물을 경엽처리를 진행한 후 생육조사를 진행했다. Seed bioassay의 경우, petri dish 위에 톨페스큐 종자 20개가 치상하고, 애기수영 지상부 추출물과 지하부 추출물을 각각 20,000 mg L^-1, 10,000 mg L^-1, 5,000 mg L^-1, 2,500 mg L^-1 농도로 serial dilution 하여 1mL씩 분주한 뒤, 일주일 뒤에 발아한 종자에 대해 생체중을 조사하고 Prizm 프로그램을 이용해 IC₅₀을 구하였다. 경엽처리의 경우, 톨페스큐 종자 파종4주 뒤에 IC₅₀값이 더 낮았던 지상부 추출물을 100,000 mg L^-1, 50,000 mg L^-1, 25,000 mg L^-1, 12,500 mg L^-1, 6,250 mg L^-1 농도로 serial dilution 한 뒤 5mL씩 일주일 간격으로 3회 경엽처리를 진행하였고, 마지막 처리 일주일 뒤 초장, 근장, 생체중, 건물중을 조사하였다. Seed bioassay 결과, 애기수영 지하부 추출물에 대한 톨페스큐의 IC₅₀값은 3274가 나왔고, 애기수영 지상부 추출물에 대한 톨페스큐의 IC₅₀값은 2728가 나왔다. Seed bioassay 결과를 바탕으로 효과적 이 었던 지상부 추출물을 이용해 톨페스큐 경엽처리를 진행하였다. 애기수영 지상부 추출물 경엽처리 결과, 톨페스큐 초장과 생체중이 추출물 처리량이 높아짐에 따라 낮아졌으며, 100,000 mg L^-1 처리구는 Control과 비교해 유의적으로 감소하였고, 처리량이 높아짐에 따라 근장이 감소했지만, 유의적인 차이는 없었다. 그리고 건물중은 100,000 mg L^-1 처리구가 Control, 12,500 mg L^-1, 6,250 mg L^-1 처리구와 비교해 유의적으로 낮았다.