Application Of Chlorimuron-ethyl Research Articles

Weed management options in drum seeded wetland rice

High labour requirement and cost for raising nursery and transplanting of the seedlings has necessitated the shift from transplanted rice to direct-seeded rice. To reduce the requirement of large quantity of seeds, incidence of pests and diseases in broadcasting and to ensure uniform seed distribution for consistent crop growth and easier maintenance, mechanization is needed in direct-seeded rice. The major constraint experienced in wet DSR is the occurrence of high weed infestation as emerging seedlings in direct-sown fields are less competitive with concurrently emerging weeds. An experiment was conducted at M. S. Swaminathan Rice Research Station, Moncompu, Kerala Agricultural University during kharif and rabi 2021-22, with eight treatments and three replications in randomised complete block design to identify suitable cost-effective agronomic management practices to enhance the productivity of drum seeded rice and to maximise its resource-use-efficiency. The results revealed wet DSR using drumseeder as a viable crop establishment method for reducing the seed requirement, cultivation time, energy, cost of cultivation, pest and disease infestation, minimise plant stress due to transplanting and sustaining yield. There was significant variation in the yield and yield attributes in drum seeding depending on the weed management strategies adopted viz., two conoweedings, post emergent herbicide application, pre followed by post emergent herbicide application, post emergent herbicide application followed by conoweeding. Post-emergence application of Chlorimuron ethyl + Metsulfuron methyl @ 0.004 kg/ha and Penoxsulam + Cyhalofop butyl @ 0.135 kg/ha as tank mix at 18 DAS followed by conoweeding at 30 DAS was found economical in drum seeding which was on par yield with broadcasted crop yield under post emergent herbicide application.

CHLORIMURON-ETHYL IN CONVENTIONAL AND TRANSGENIC SOYBEAN CULTIVARS UNDER WATER DEFICIT STRESS

ABSTRACT Water deficit is a limiting factor for the soybean yield; it triggers different physiological and anatomical adaptations that have deleterious effects on the plants and can affect the selectivity of herbicides, causing production losses. In this context, the objective of this work was to evaluate the action of the chlorimuron-ethyl herbicide when applied at different stages of soybean plants, using conventional and transgenic cultivars, and different soil water potentials. A rate of 20 g ha-1 of the chlorimuron-ethyl herbicide was applied to two soybean cultivars (MG/BR46-Conquista - conventional, and BRS-Valiosa-RR - transgenic) at two phenological stages (V2 - first fully expanded trifoliate leaves, and V4 - third fully expanded trifoliate leaves), using three soil water potentials (-0.03 MPa, -0.07 MPa, and -0.5 MPa). Phytotoxicity, and plant height were evaluated at 3, 7, 14, and 21 days after the herbicide application. The shoot dry weight, root dry weight, and root system nodulation were evaluated. The soybean plants had lower phytotoxicity when subjected to application of chlorimuron-ethyl under water deficit conditions. The use of chlorimuron-ethyl reduced the growth and biomass of soybean plants and affected the plants' root system nodulation. The transgenic cultivar (BRS-Valiosa-RR) presented better performance when subjected to a moderate water deficit (-0.07 MPa), which contributes to biological nitrogen fixation.

Seletividade de herbicidas aplicados em pré e pós-emergência da cultura do cártamo

O cultivo do cártamo tem aumentado nos últimos anos, principalmente para a produção de biodiesel. O controle de plantas daninhas a fim de evitar perdas na produtividade da cultura faz se necessário. Desta forma, uma alternativa que surge é o uso de herbicidas seletivos para a cultura. Objetivou-se verificar a seletividade de herbicidas em pré e pós-emergência para a cultura do cártamo. Foram conduzidos dois experimentos adotando-se delineamento em blocos casualizados com quatro repetições. Para o primeiro experimento com aplicações em pré-emergência os tratamentos foram arranjados em esquema fatorial 6 x 2 + 1, enquanto que para o segundo experimento, com as aplicações em pós-emergência os tratamentos foram dispostos em esquema fatorial 7 x 2 + 1. Em ambos experimentos, o fator A correspondeu aos diferentes herbicidas e o fator B às doses utilizadas, e o tratamento adicional consistiu de testemunha sem aplicação de herbicidas. Foram realizadas avaliações visuais de fitointoxicação nas plantas aos 7, 14 e 21 dias após a aplicação, altura de plantas, estande e produtividade. Os herbicidas chlorimuron-ethyl (20 e 40 g i.a. ha-1), flumioxazin (50 e 100 g i.a. ha-1), imazaquin (161 e 322 g i.a. ha-1), s-metolachlor (1440 e 24000 g i.a. ha-1) e sulfentrazone (300 g i.a. ha-1), aplicados em pré-emergência, e os herbicidas sethoxydim (184 g i.a. ha-1), fluazifop-p-butyl (375 e 750 g i.a. ha-1) haloxyfop-methyl (60 e 120 g i.a. ha-1) e clethodim (108 g i.a. ha-1), aplicados em pós-emergência foram seletivos para a cultura do cártamo.

Efficient degradation of chlorimuron-ethyl by a bacterial consortium and shifts in the aboriginal microorganism community during the bioremediation of contaminated-soil

Excessive application of chlorimuron-ethyl has led to soil contamination and limited crop rotation; therefore, tactics to decrease and eliminate residual chlorimuron-ethyl in the environment have attracted increasing attention. In this study, two chlorimuron-ethyl-degrading bacterial strains (Rhodococcus sp. D310-1; Enterobacter sp. D310-5) were used to ferment and prepare a chlorimuron-ethyl-degrading bacterial consortium. To improve the degradation efficiency of the bacterial consortium, the cultivation conditions were optimized using response surface methodology (RSM). The maximum biodegradation rate (87.42%) was obtained under optimal conditions (carbon concentration, 9.21gL−1; temperature, 26.15°C; pH, 6.95). The rate of chlorimuron-ethyl degradation by the bacterial consortium in the chlorimuron-ethyl-contaminated soil was monitored and reached 80.02% at the end of a 60-d incubation period. Illumina MiSeq sequencing results showed that microbial diversity was high, and 33 phyla were identified in the analyzed samples. Proteobacteria, Acidobacteria, Acidobacteria, Firmicutes and Bacteroidetes were present in relatively high abundances in the samples. The bacterial consortium made a positive impact on the remediation of chlorimuron-ethyl-contaminated soil and somewhat altered the composition of the bacterial community in the chlorimuron-ethyl-contaminated soil. These findings provide highly valuable information on the production of bacterial consortium for the remediation of chlorimuron-ethyl and other sulfonylurea-herbicide-contaminated soil.

Efficacy of chlorimuron for controlling weeds in soybean

The field was infested with monocot weeds like Echinochloa colona, Cyperus iria whereas dicot weeds Alternanthera philoxiroides, Eclipta alba, Commelina benghalensis and Phyllanthus niruri were less dominant in soybean. The application of Chlorimuron-ethyl 24 g/ha as early post-emergence along with mechanical weeding was most effective in paralyzing the weed growth to that of chlorimuron-ethyl (12, 24, 36, 48 and 72 g/ha) and mechanical weeding at 20 DAS. The application of chlorimuron-ethyl herbicide at 24 g/ha as early post-emergence along with mechanical weeding was significant superior for growth parameters, yield attributes and seed yield (1.61 t/ha) of soybean than rest of the treatments without any phytotoxicity on soybean plants and was found more remunerative in terms of NMR (`20023.8) and B-C ratio (2.06) than application of chlorimuron-ethyl herbicide at 12 g/ha to 72 g/ha, as early post-emergence. Two hand weedings (20 and 40 DAS) proved to be the best in terms of yield (1.69 t/ha grain, 3.49 t/ha stover); however, NMR (`20011.7/ha) was almost at par to chlorimuron 24 g along with mechanical weeding (`20023.8/ha).

Chemical weed management in castor

A field experiment was conducted to study the effect of early post-emergence herbicide namely chlorimuron-ethyl and quizalofop-ethyl on weeds in castor and also to evaluate its weed control efficiency over hand weeding and power operated weeding. It was revealed that pre-emergence application of pendimethalin at 1.0 kg/ha followed by mechanical weeding twice at 20 and 40 DAS has recorded lower weed density with higher weed control efficiency. Mechanical weeding twice, pre-emergence application of pendimethalin followed by chlorimuron-ethyl at 0.01 kg/ha or mechnical weeding twice on 20 and 40 DAS have recorded higher yield and economics. Mechanical weeding twice (2.58 kg/ha), pre emergence application of pendimethalin at 1.0 kg/ha followed by mechanical weeding twice at 20 and 40 DAS (2.57 kg/ha) or post-emergence application of chlorimuron-ethyl at 0.01 kg/ha (2.47 kg/ha) have recorded numerically higher yield and B: C ratio.

Microbial community dynamics during the bioremediation process of chlorimuron-ethyl-contaminated soil by Hansschlegelia sp. strain CHL1.

Long-term and excessive application of chlorimuron-ethyl has led to a series of environmental problems. Strain Hansschlegelia sp. CHL1, a highly efficient chlorimuron-ethyl degrading bacterium isolated in our previous study, was employed in the current soil bioremediation study. The residues of chlorimuron-ethyl in soils were detected, and the changes of soil microbial communities were investigated by phospholipid fatty acid (PLFA) analysis. The results showed that strain CHL1 exhibited significant chlorimuron-ethyl degradation ability at wide range of concentrations between 10μg kg-1 and 1000μg kg-1. High concentrations of chlorimuron-ethyl significantly decreased the total concentration of PLFAs and the Shannon-Wiener indices and increased the stress level of microbes in soils. The inoculation with strain CHL1, however, reduced the inhibition on soil microbes caused by chlorimuron-ethyl. The results demonstrated that strain CHL1 is effective in the remediation of chlorimuron-ethyl-contaminated soil, and has the potential to remediate chlorimuron-ethyl contaminated soils in situ.

Effects of chlorimuron-ethyl application with or without urea fertilization on soil ammonia-oxidizing bacteria and archaea

Chlorimuron-ethyl (CE) has been widely used in modern agriculture, but little is known regarding the influence of CE on ammonia-oxidizing bacteria (AOB) and archaea (AOA) populations in soils. In this study, microcosm incubation of aquic brown soil was conducted for 60 d. Associated changes in the population sizes of AOB and AOA in response to CE application with or without urea fertilization were examined via quantitative real-time PCR (qPCR) assays of the ammonia monooxygenase gene (amoA). The half-life of CE ranged from 11.80 d to 14.54 d in the tested soil. Compared to the untreated control, the application of CE alone had no strong effects on soil pH, and urea fertilization temporarily increased soil pH in the first 7 days. The abundance of the AOA amoA gene was greater than the abundance of the AOB amoA gene in all treatments, but both were significantly suppressed by CE application in a dose-dependent manner. Urea fertilization generally increased AOB and AOA amoA gene abundances, except that the AOA amoA gene level was slightly reduced at the early stage of the incubation period. AOB and AOA preferred different N levels for growth, with AOB only growing significantly at high NH4+ levels and AOA growing substantially at low NH4+ levels. The stimulation effects of urea fertilization on AOA and AOB amoA gene abundances were strongly suppressed by the CE application. This study indicated that the CE application substantially suppressed soil nitrification via inhibiting the AOB and AOA population regardless of urea fertilization, which resulted in significant changes in the soil NH4+-N and NO3−-N levels. Furthermore, AOB and AOA inhabiting separate ecological niches with different NH4+ levels played various roles in N cycling.

Responses of soil nitrogen-fixing, ammonia-oxidizing, and denitrifying bacterial communities to long-term chlorimuron-ethyl stress in a continuously cropped soybean field in Northeast China

Chlorimuron-ethyl is a type of long-residual herbicide applied widely to soybean fields in China, but little information is available about the long-term impact of this herbicide on soil nitrogen-transforming microbial communities. Soil samples (0–20 cm) were collected from three treatments (no, 5-year and 10-year application of chlorimuron-ethyl) in a continuously cropped soybean field. Plate count (CFU), most probable number (MPN) count, and clone library analyses were conducted to investigate the abundance and composition of nitrogen-fixing, ammonia-oxidizing, and denitrifying bacterial communities, and a chlorate inhibition method was adopted to measure the soil nitrification potential. Long-term chlorimuron-ethyl application reduced the abundance of soil culturable nitrogen-fixing, ammonia-oxidizing, and denitrifying bacteria. Moreover, chlorimuron-ethyl decreased the diversity of nitrogen-fixing and ammonia-oxidizing bacteria but promoted that of denitrifying bacteria. Chlorimuron-ethyl restrained some uncultured nitrogen-fixing bacteria, ammonia-oxidizing bacteria Nitrosospira sp. cluster 3a and 3d, and some novel or putative denitrifying bacteria. The nitrogen-fixing bacteria were closely related to Bradyrhizobium sp., ammonia-oxidizing bacteria Nitrosospira sp. cluster 3b and 3c, and most denitrifying bacteria were resistant to chlorimuron-ethyl. There was a negative correlation between the nitrification potential and the residual amount of soil chlorimuron-ethyl (R2 = 0.88, n = 3, P < 0.05). Therefore, long-term application of chlorimuron-ethyl in the continuously cropped soybean field could seriously disturb soil N-transforming communities, and might impact soybean soil biological quality and soybean growth. Further studies should address rational amendment models of this herbicide to reduce the possible ecological risks of long-term application of this herbicide to soybean fields.

Effects of long-term chlorimuron-ethyl application on the diversity and antifungal activity of soil Pseudomonas spp. in a soybean field in Northeast China

The herbicide chlorimuron-ethyl has been applied widely for weed control in farmland, especially in soybean fields in China over the past decade, but the chronic effects of this herbicide on soil microorganisms, particularly Pseudomonas spp., is not well understood. Taking a continuously cropped soybean field in the town of Fuyuan-a soybean production base of Heilongjiang Province in Northeast China-as a case study, soil samples were collected from plots having received 0-, 5-, and 10-year applications of chlorimuron-ethyl (30 g active component of chlorimuron-ethyl/ha/year) to study the abundance and diversity of Pseudomonas spp. Meanwhile, an in vitro assay was used to examine the antifungal activities of isolated Pseudomonas spp. against soil-borne pathogens (Fusarium graminearum, Fusarium oxysporum, and Rhizoctonia solani) causing soybean root rot disease. The production of siderophore, hydrogen cyanide (HCN), and lytic enzymes (cellulase, pectinase, and chitinase) by Pseudomonas spp. was also investigated. With 5- and 10- year chlorimuron-ethyl application, the numbers of soil Pseudomonas spp. decreased from 121 x 10(2) CFU/g dry soil in the control to 40 x 10(2) CFU/g dry soil and 13 x 10(2) CFU/g dry soil, and the Shannon index values decreased from 6.23 to 3.71 and 1.73, respectively. The numbers of antifungal Pseudomonas spp. also decreased, and the proportions of Pseudomonas spp. with antifungal activities against the different test pathogens altered. All the antifungal Pseudomonas spp. could produce siderophore and HCN but not lytic enzymes. The results suggest that long-term application of chlorimuron-ethyl in continuously cropped soybean field had negative effects on the abundance and diversity of soil Pseudomonas spp., including species with different antifungal activities against pathogens. Siderophore and HCN rather than lytic enzymes formed the antifungal metabolites of Pseudomonas spp., and the number of antifungal Pseudomonas that can produce siderophore and HCN decreased markedly under application of chlorimuron-ethyl, especially after 10-year application.

Potencial de uso dos herbicidas chlorimuron-ethyl, imazethapyr e cloransulam-methyl na cultura do feijão

O objetivo deste trabalho foi avaliar a seletividade dos herbicidas chlorimuron-ethyl, imazethapyr e cloransulam-methyl, aplicados em associação com o herbicida fomesafen, a dez cultivares de feijão. O experimento foi conduzido no município de Rio Verde-GO, no plantio das águas, na safra de 2005/2006. O delineamento experimental utilizado foi de blocos ao acaso, em parcelas subdivididas, com três repetições, sendo o fator da parcela principal os tratamentos com herbicidas [fomesafen (225 g ha-1 ); fomesafen (225 g ha-1 ) + chlorimuron-ethyl (7,5 g ha-1 ); fomesafen (225 g ha-1 ) + imazethapyr (50 g ha-1); fomesafen (225 g ha-1) + cloransulam-methyl (30,24 g ha-1); e testemunha sem herbicida]; e o da subparcela, os cultivares (BRS Grafite, BRS Horizonte, Pérola, BRS Pitanga, BRS Pontal, BRS Requinte, BRS Supremo, BRS Timbó, BRS Valente e BRS Vereda). As parcelas foram mantidas capinadas, para que não houvesse interferência das plantas daninhas. Os tratamentos com herbicidas foram fitotóxicos; todavia, de forma geral, os sintomas mais severos foram verificados no tratamento que continha chlorimuron-ethyl. A associação de fomesafen com chlorimuron-ethyl provocou as maiores reduções na altura das plantas e no acúmulo de massa da parte aérea das plantas secas, além de prolongar o ciclo de maturação de todos os cultivares. A aplicação isolada de fomesafen reduziu a produtividade de grãos dos cultivares BRS Timbó e BRS Vereda. Quando se adicionou o imazethapyr ao fomesafen, observou-se redução na produtividade dos cultivares BRS Supremo, BRS Timbó e BRS Vereda. A adição de cloransulam-methyl, além de reduzir a produtividade desses três cultivares, também diminuiu a produtividade do cultivar BRS Requinte. Os cultivares Pérola, BRS Pitanga, BRS Pontal e BRS Valente não tiveram suas produtividades reduzidas pela mistura chlorimuron-ethyl + fomesafen. O imazethapyr mostrou potencial para ser utilizado na cultura do feijão.

Soybean response to simulated dicamba/diflufenzopyr drift followed by postemergence herbicides

Five field experiments were conducted in 2007 to determine the effect of simulated dicamba/diflufenzopyr drift followed by postemergence applications of chlorimuron-ethyl, imazethapyr or bentazon on soybean ( Glycine max Merr.) crop injury, dry weight, height and yield. In the absence of a postemergence herbicide, as the dose of simulated dicamba/diflufenzopyr increased there was an increase in soybean injury and a decrease in dry weight, height and yield. The application of registered postemergence herbicides following simulated dicamba/diflufenzopyr drift resulted in a synergistic increase in crop injury in some environments. There was no synergistic response in respect to dry weight and height when simulated drift was followed by postemergence herbicides. A synergistic yield response was observed with yield being decreased 4–7% more than expected due to simulated dicamba/diflufenzopyr drift followed by the application of chlorimuron-ethyl. No synergistic yield response was observed for dicamba/diflufenzopyr drift followed by either imazethapyr or bentazon.

Bio-efficacy of post-emergence herbicides for control of complex weed flora in drum-seeded rice (Oryza sativa)

A field experiment was conducted during the rainy season of 2012 and 2013 at Gambharipali, Bargarh Odisha, to study the bio-efficacy of various herbicides on weeds, yield and economics of drum-seeded rice (Oryza sativa L.). Sole application of chlorimuron ethyl + metsulfuron methyl @ 4 g/ha, ethoxysulfuron @ 18 g/ha and 2, 4-D ethyl ester @ 400 g/ha showed selectivity towards broad-leaf weeds, whereas fenoxaprop-p-ethyl @ 60 g/ha showed selectivity towards grasses. Tank-mix application of chlorimuron ethyl + metsulfuron methyl with fenoxaprop-p-ethyl (4+60 g/ha) proved to be the most effective in minimizing the density (10.57/m2), biomass (4.07 g/m2) of weeds and enhancing the weed-control efficiency (95.7%), grain yield (5.68 t/ha), N, P and K uptake by crop, net returns ( 30,439/ha) and benefit: cost ratio (0.61).

QTLs associated with chlorimuron ethyl sensitivity in soybean: Effects on seed yield and related traits

Soybean, Glycine max (L.) Merr., genotypes are known to differ in chlorimuron ethyl sensitivity (CS). Earlier we have reported two putatively independent marker loci linked to two quantitative trait loci (QTLs) controlling CS in a soybean population derived from a cross of PI97100 (sensitive to chlorimuron ethyl) and ‘Coker 237’ (tolerant to chlorimuron ethyl). The objective of the present study was to quantify the association of the two marker loci with seed yield and related traits in this soybean population following application of chlorimuron ethyl. Phenotypic data were collected for 111 F2-derived lines of the cross grown in replicated plots at Athens, G.A., in 1994 and 1995, and at Blackville, S.C., in 1995. The two CS marker loci explained as much as 50% of the genetic variation in seed yield and seed number m-2, but had no association with seed weight, plant height, lodging, seed protein, and seed oil. There were no epistatic interactions between the two marker loci for any of the traits. The marker locus (cr168-1 on USDA linkage group E) linked to the major CS QTL explained between 13 and 23% of the variation in seed yield. The Coker 237 allele at this locus was associated with decreased CS and increased seed yield. The marker locus (Blt015-2 on an unknown linkage group) linked to the minor CS QTL accounted for a maximum of 11% of the variation in seed yield. The Coker 237 allele at this locus was associated with an increase in CS and a decrease in seed yield. The association of the two marker loci with seed number m-2 strongly resembled their association with seed yield. Seed yield had a strong positive correlation (r=0.74 – 0.94) with seed number m-2, and the effect of chlorimuron ethyl on seed yield was due mainly to its effect on seed number m-2 rather than seed weight.