Herbicide and Cover Crop Residue Integration forAmaranthusControl in Conservation Agriculture Cotton and Implications for Resistance Management

Conservation agriculture (CA) practices are threatened by glyphosate-resistant Palmer amaranth. Integrated control practices including PRE herbicides and high-residue CA systems can decreaseAmaranthusemergence. Field experiments were conducted from autumn 2006 through crop harvest in 2009 at two sites in Alabama to evaluate the effect of integrated weed management practices onAmaranthuspopulation density and biomass, cotton yield, and economics in glyphosate-resistant cotton. Horizontal strips included four CA systems with three cereal rye cover crop seeding dates and a winter fallow (WF) CA system compared to a conventional tillage (CT) system. Additionally, vertical strips of four herbicide regimes consisted of: broadcast, banded, or no PRE applications ofS-metolachlor (1.12 kg ai ha−1) followed by (fb) glyphosate (1.12 kg ae ha−1) applied POST fb layby applications of diuron (1.12 kg ai ha−1) plus MSMA (2.24 kg ai ha−1) or the LAYBY application alone. Early-seasonAmaranthusdensity was reduced in high-residue CA in comparison to the CA WF systems in 2 of 3 yr.Amaranthusdensities in herbicide treatments that included a broadcast PRE application were lower at three of five sampling dates compared to banding early-season PRE applications; however, the differences were not significant during the late season and cotton yields were not affected by PRE placement. High-residue conservation tillage yields were 577 to 899 kg ha−1more than CT, except at one site in 1 yr when CT treatment yields were higher. CA utilizing high-residue cover crops increased net returns over CT by $100 ha−1or more 2 out of 3 yr at both locations. High-residue cover crop integration into a CA system reducedAmaranthusdensity and increased yield over WF systems; the inclusion of a broadcast PRE application can increase early-seasonAmaranthuscontrol and might provide additional control when glyphosate-resistantAmaranthuspopulations are present.

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Horseweed (Conyza canadensis) Suppression from Cover Crop Mixtures and Fall-Applied Residual Herbicides

Weed Technology ◽

10.1017/wet.2018.111 ◽

2019 ◽

Vol 33 (2) ◽

pp. 303-311 ◽

Cited By ~ 4

Author(s):

Kara B. Pittman ◽

Jacob N. Barney ◽

Michael L. Flessner

Keyword(s):

Cover Crops ◽

Weed Management ◽

Cover Crop ◽

Field Experiments ◽

Late Spring ◽

Integrated Weed Management ◽

Management Approach ◽

Late Winter ◽

Cereal Rye ◽

Crimson Clover

AbstractHorseweed is a problematic weed to control, especially in no-tillage production. Increasing cases of herbicide resistance have exacerbated the problem, necessitating alternative control options and an integrated weed management approach. Field experiments were conducted to evaluate horseweed suppression from fall-planted cover crop monocultures and mixtures as well as two fall-applied residual herbicide treatments. Prior to cover crop termination, horseweed density was reduced by 88% to 96% from cover crops. At cover crop termination in late spring, cereal rye biomass was 7,671 kg ha–1, which was similar to cereal rye–containing mixtures (7,720 kg ha–1) but greater than legumes in monoculture (3,335 kg ha–1). After cover crops were terminated in late spring using a roller crimper, corn and soybeans were planted and horseweed was evaluated using density counts, visible ratings, and biomass collection until harvest. Forage radish winterkilled, offering no competition in late winter or biomass to contribute to horseweed suppression after termination. Excluding forage radish in monoculture, no difference in horseweed suppression was detected between cereal rye–containing cover crops and legumes (crimson clover and hairy vetch) in monoculture. Likewise, horseweed suppression was similar between monocultures and mixtures, with the exception of one site-year in which mixtures provided better suppression. In this experiment, the cover crop treatments performed as well as or better than the fall-applied residual herbicides, flumioxazin+paraquat and metribuzin+chlorimuron-ethyl. These results indicate that fall-planted cover crops are a viable option to suppress horseweed and can be an effective part of an integrated weed management program. Furthermore, cover crop mixtures can be used to gain the benefits of legume or brassica cover crop species without sacrificing horseweed suppression.

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Influence of Weed Management Practices and Crop Rotation on Glyphosate-Resistant Horseweed Population Dynamics and Crop Yield

Weed Science ◽

10.1614/ws-06-187.1 ◽

2007 ◽

Vol 55 (5) ◽

pp. 508-516 ◽

Cited By ~ 31

Author(s):

Vince M. Davis ◽

Kevin D. Gibson ◽

Thomas T. Bauman ◽

Stephen C. Weller ◽

William G. Johnson

Keyword(s):

Population Dynamics ◽

Crop Rotation ◽

Crop Yield ◽

Cover Crops ◽

Weed Management ◽

Management Practices ◽

Plant Density ◽

Management Systems ◽

Integrated Weed Management ◽

Rapid Decline

Horseweed is an increasingly problematic weed in soybean because of the frequent occurrence of glyphosate-resistant (GR) biotypes. The objective of this study was to determine the influence of crop rotation, winter wheat cover crops (WWCC), residual nonglyphosate herbicides, and preplant herbicide application timing on the population dynamics of GR horseweed and crop yield. A field study was conducted at a site with a moderate infestation of GR horseweed (approximately 1 plant m−2) with crop rotation (soybean–corn or soybean–soybean) as main plots and management systems as subplots. Management systems were evaluated by quantifying horseweed plant density, seedbank density, and crop yield. Crop rotation did not influence in-field horseweed or seedbank densities at any data census timing. Preplant herbicides applied in the spring were more effective at reducing horseweed plant densities than when applied in the previous fall. Spring-applied, residual herbicide systems were the most effective at reducing season long horseweed densities and protecting crop yield because horseweed in this region behaves primarily as a summer annual weed. Horseweed seedbank densities declined rapidly in the soil by an average of 76% for all systems over the first 10 mo before new seed rain. Despite rapid decline in total seedbank density, seed for GR biotypes remained in the seedbank for at least 2 yr. Therefore, to reduce the presence of GR horseweed biotypes in a local no-till weed flora, integrated weed management (IWM) systems should be developed to reduce total horseweed populations based on the knowledge that seed for GR biotypes are as persistent in the seed bank as glyphosate-sensitive (GS) biotypes.

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Suppression of Glyphosate-resistant Canada Fleabane (Conyza canadensis) in Corn with Cover Crops Seeded after Wheat Harvest the Previous Year

Weed Technology ◽

10.1017/wet.2018.19 ◽

2018 ◽

Vol 32 (3) ◽

pp. 244-250 ◽

Cited By ~ 7

Author(s):

Taïga B. Cholette ◽

Nader Soltani ◽

David C. Hooker ◽

Darren E. Robinson ◽

Peter H. Sikkema

Keyword(s):

Cover Crops ◽

Weed Management ◽

Cover Crop ◽

Management Strategies ◽

Late Summer ◽

Growing Season ◽

Integrated Weed Management ◽

Crop Species ◽

Herbicide Resistant ◽

Crimson Clover

AbstractGlyphosate-resistant (GR) and multiple herbicide–resistant (groups 2 and 9) Canada fleabane have been confirmed in 30 and 23 counties in Ontario, respectively. The widespread incidence of herbicide-resistant Canada fleabane highlights the importance of developing integrated weed management strategies. One strategy is to suppress Canada fleabane using cover crops. Seventeen different cover crop monocultures or polycultures were seeded after winter wheat harvest in late summer to determine GR Canada fleabane suppression in corn grown the following growing season. All cover crop treatments seeded after wheat harvest suppressed GR Canada fleabane in corn the following year. At 4 wk after cover crop emergence (WAE), estimated cover crop ground cover ranged from 31% to 68%, a density of 124 to 638 plants m–2, and a range of biomass from 29 to 109 g m–2, depending on cover crop species. All of the cover crop treatments suppressed GR Canada fleabane in corn grown the following growing season from May to September compared to the no cover crop control. Among treatments evaluated, annual ryegrass (ARG), crimson clover (CC)/ARG, oilseed radish (OSR)/CC/ARG, and OSR/CC/cereal rye (CR) were the best treatments for the suppression of GR Canada fleabane in corn. ARG alone or in combination with CC provided the most consistent GR Canada fleabane suppression, density reduction, and biomass reduction in corn. Grain corn yields were not affected by the use of the cover crops evaluated for Canada fleabane suppression.

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Evaluation of Herbicide Programs for Use in a 2,4-D–Resistant Soybean Technology for Control of Glyphosate-Resistant Palmer Amaranth (Amaranthus palmeri)

Weed Technology ◽

10.1614/wt-d-15-00129.1 ◽

2016 ◽

Vol 30 (2) ◽

pp. 366-376 ◽

Cited By ~ 11

Author(s):

M. Ryan Miller ◽

Jason K. Norsworthy

Keyword(s):

Weed Management ◽

Field Experiments ◽

Palmer Amaranth ◽

Integrated Weed Management ◽

Amaranthus Palmeri ◽

Early Season ◽

Fully Integrated ◽

Soil Seedbank ◽

High Level ◽

Herbicide Programs

Two separate field experiments were conducted over a 2-yr period in Fayetteville, AR, during 2012 and 2013 to (1) evaluate POST herbicide programs utilizing a premixture of dimethylamine (DMA) salt of glyphosate + choline salt of 2,4-D in a soybean line resistant to 2,4-D, glyphosate, and glufosinate and (2) determine efficacy of herbicide programs that begin with PRE residual herbicides followed by POST applications of 2,4-D choline + glyphosate DMA on glyphosate-resistant Palmer amaranth. In the first experiment, POST applications alone that incorporated the use of residual herbicides with the glyphosate + 2,4-D premixture provided 93 to 99% control of Palmer amaranth at the end of the season. In the second experiment, the use of flumioxazin, flumioxazin + chlorimuron methyl, S-metolachlor + fomesafen, or sulfentrazone + chloransulam applied PRE provided 94 to 98% early-season Palmer amaranth control. Early-season control helped maintain a high level of Palmer amaranth control throughout the growing season, in turn resulting in fewer reproductive Palmer amaranth plants present at soybean harvest compared to most other treatments. Although no differences in soybean yield were observed among treated plots, it was evident that herbicide programs should begin with PRE residual herbicides followed by POST applications of glyphosate + 2,4-D mixed with residual herbicides to minimize late-season escapes and reduce the likelihood of contributions to the soil seedbank. Dependent upon management decisions, the best stewardship of this technology will likely rely on the use multiple effective mechanisms of action incorporated into a fully integrated weed management system.

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Evaluation of Cereal and Brassicaceae Cover Crops in Conservation-Tillage, Enhanced, Glyphosate-Resistant Cotton

Weed Technology ◽

10.1614/wt-d-10-00040.1 ◽

2011 ◽

Vol 25 (1) ◽

pp. 6-13 ◽

Cited By ~ 37

Author(s):

Jason K. Norsworthy ◽

Marilyn McClelland ◽

Griff Griffith ◽

Sanjeev K. Bangarwa ◽

Joshua Still

Keyword(s):

Herbicide Resistance ◽

Cover Crops ◽

Weed Management ◽

Conservation Tillage ◽

White Mustard ◽

Early Season ◽

Pitted Morningglory ◽

Second Year ◽

Herbicide Programs ◽

Selection Of

Research was conducted for 2 yr at Marianna, AR, to determine whether the fall-planted cover crops rye, wheat, turnip, and a blend of brown and white mustard (Caliente) would aid weed management programs in conservation-tilled, enhanced, glyphosate-resistant cotton. Wheat and rye easily were established both years and turnip and mustard blend stands were better in the second year. The cover crops alone were more suppressive of Palmer amaranth, pitted morningglory, and goosegrass in 2007 than in 2008. Rye was generally superior to wheat in suppressing the three evaluated weeds. Once herbicides were applied, there were seldom differences among cover crops for a particular herbicide program as a result of the highly efficacious herbicide programs. Cotton yields were not affected by wheat, rye, or the mustard blend, but yields were lowest in plots that followed turnip both years, possibly because of allelopathy. Integration of cover crops, especially cereals, into conservation-tilled, glyphosate-resistant cotton aided early-season weed management and could reduce the selection of glyphosate for herbicide resistance.

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Cover Crop and Postemergence Herbicide Integration for Palmer amaranth Control in Cotton

Weed Technology ◽

10.1017/wet.2017.10 ◽

2017 ◽

Vol 31 (3) ◽

pp. 348-355 ◽

Cited By ~ 3

Author(s):

Matthew S. Wiggins ◽

Robert M. Hayes ◽

Robert L. Nichols ◽

Lawrence E. Steckel

Keyword(s):

Cover Crops ◽

Weed Management ◽

Cover Crop ◽

Field Experiments ◽

Palmer Amaranth ◽

Cereal Rye ◽

Crimson Clover ◽

Annual Grasses ◽

Winter Annual ◽

Hand Weeding

Field experiments were conducted to evaluate the integration of cover crops and POST herbicides to control glyphosate-resistant Palmer amaranth in cotton. The winter-annual grasses accumulated the greatest amount of biomass and provided the most Palmer amaranth control. The estimates for the logistic regression would indicate that 1540 kg ha−1would delay Palmer amaranth emerging and growing to 10 cm by an estimated 16.5 days. The Palmer amaranth that emerged in the cereal rye and wheat cover crop treatments took a longer time to reach 10 cm compared to the hairy vetch and crimson clover treatments. POST herbicides were needed for adequate control of Palmer amaranth. The glufosinate-based weed control system provided greater control (75% vs 31%) of Palmer amaranth than did the glyphosate system. These results indicate that a POST only herbicide weed management system did not provide sufficient control of Palmer amaranth, even when used in conjunction with cover crops that produced a moderate level of biomass. Therefore, future recommendations for GR Palmer amaranth control will include integrating cover crops with PRE herbicides, overlaying residual herbicides in-season, timely POST herbicide applications, and hand weeding in order to achieve season-long control of this pest.

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Influence of Integrated Weed Management and Tillage Methods on Soil Physical and Chemical Properties in Maize Production

International Journal of Plant & Soil Science ◽

10.9734/ijpss/2020/v32i1530373 ◽

2020 ◽

pp. 43-64

Author(s):

G. C. Michael ◽

S. A. Gisilanbe ◽

S. O. Dania ◽

A. D. Manthy ◽

O. Fagbola

Keyword(s):

Soil Properties ◽

Cover Crops ◽

Weed Management ◽

Field Experiments ◽

Block Design ◽

Chemical Properties ◽

Experimental Period ◽

Integrated Weed Management ◽

Small Scale ◽

Maize Production

A two year field experiments were conducted at the College of Agriculture Teaching and Research Farm, Jalingo, Taraba State, Nigeria, to evaluate the integrated use of 25% rates of selected herbicides mixtures (atrazine-pendimethalin (AP1) or primextra (PX1) and cover crops (a vegetable cowpea, "Akidi" (A), Melon (M) and Sweet potato (S) planted sole or mixed at 20,000 stands/ha (1) or 40,000 stands/ha (3) under manual (MT) and tractor tillage (TT) methods used primarily for weed control on soil properties and maize production. The experimental design was a split plot arrangement in a randomized complete block design replicated three times. Tractor Tillage (TT) and Manual Tillage (MT) were the main treatments. The sub treatments included ten integrated weed management (IWM), AP1AI, AP1AS1, AP1S3, AP1MS3, AP1AMS3, PX1A1, PX1AS1, PX1S3, PX1MS3, PX1AMS3 in addition to Weeded 3+6 Weeks After Planting (WAP) (C1) and unweeded(C2) as controls. Descriptive statistics and Analysis of Variance were used to analyze data and the treatment means were compared using standard error at 5%. The level of Na, organic carbon, TN, %clay and %fine sand were higher in MT than TT during the experimental period while Mg, pH, %silt and clay were higher in TT than in MT. Herbicide groups did not significantly influenced soil properties in this study. The Ca2+, K+ and A-VP in all IWM treated plots were higher than the value in C2 . Treatments having Akidi (A1, AS1, AMS3) recorded higher OC than those without (S3, MS3). Therefore, MT improves soil condition and should be used in small scale farming and where TT is used, special consideration of soil type and frequency of use should be moderated. Use of IWM ameliorates fertility losses observed, with preference for mixture with at least a leguminous component.

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Evaluation of Three Winter Cereals for Weed Control in Conservation-Tillage Nontransgenic Cotton

Weed Technology ◽

10.1614/wt-04-245r1.1 ◽

2005 ◽

Vol 19 (3) ◽

pp. 731-736 ◽

Cited By ~ 46

Author(s):

D. Wayne Reeves ◽

Andrew J. Price ◽

Michael G. Patterson

Keyword(s):

Weed Control ◽

Cover Crops ◽

Cover Crop ◽

Field Experiments ◽

Conservation Tillage ◽

Cotton Production ◽

Winter Cereal ◽

Winter Cereals ◽

Fallow System ◽

Winter Fallow

The increased use of conservation tillage in cotton production requires that information be developed on the role of cover crops in weed control. Field experiments were conducted from fall 1994 through fall 1997 in Alabama to evaluate three winter cereal cover crops in a high-residue, conservation-tillage, nontransgenic cotton production system. Black oat, rye, and wheat were evaluated for their weed-suppressive characteristics compared to a winter fallow system. Three herbicide systems were used: no herbicide, preemergence (PRE) herbicides alone, and PRE plus postemergence (POST) herbicides. The PRE system consisted of pendimethalin at 1.12 kg ai/ha plus fluometuron at 1.7 kg ai/ha. The PRE plus POST system contained an additional application of fluometuron at 1.12 kg/ha plus DSMA at 1.7 kg ai/ha early POST directed (PDS) and lactofen at 0.2 kg ai/ha plus cyanazine at 0.84 kg ai/ha late PDS. No cover crop was effective in controlling weeds without a herbicide. However, when black oat or rye was used with PRE herbicides, weed control was similar to the PRE plus POST system. Rye and black oat provided more effective weed control than wheat in conservation-tillage cotton. The winter fallow, PRE plus POST input system yielded significantly less cotton in 2 of 3 yr compared to systems that included a winter cover crop. Use of black oat or rye cover crops has the potential to increase cotton productivity and reduce herbicide inputs for nontransgenic cotton grown in the Southeast.

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Cover Crop Termination Treatment Impacts Weed Suppression Potential

Weed Science ◽

10.1017/wsc.2018.75 ◽

2019 ◽

Vol 67 (1) ◽

pp. 91-102 ◽

Cited By ~ 2

Author(s):

Erin R. Haramoto ◽

Robert Pearce

Keyword(s):

Weed Management ◽

Cover Crop ◽

Management Practices ◽

Weed Suppression ◽

Species Selection ◽

Weed Biomass ◽

Weed Density ◽

Crimson Clover ◽

Trade Offs ◽

Density And Biomass

AbstractWeed management in tobacco (Nicotiana tabacumL.) is accomplished primarily with soil-residual herbicides, cultivation, and hand removal. Management practices that reduce weed emergence, like reduced tillage and cover crop mulches, may improve weed management efficacy. Depending on cover-cropping goals, growers face trade-offs in species selection and management priorities—producing weed-suppressive mulches may lead to transplanting difficulties and soil-residual herbicide interception. Managing more complex cover crop mixtures may result in different challenges. We established on-farm trials across 4 site-years to study impacts of cover crop composition [wheat (Triticum aestivumL.) monoculture or mixture], termination treatment (early or late chemical termination or removing aboveground biomass), and soil-residual herbicides on weed density and biomass. The cover crop mixture contained cereal rye (Secale cerealeL.), crimson clover (Trifolium incarnatumL.), and hairy vetch (Vicia villosaRoth.), with canola (Brassica napusL.) at 1 site-year. The mixture typically produced more biomass than monoculture wheat, although composition had few impacts on weed density or biomass. With residual herbicides, termination treatment had few impacts on weed density, suggesting that residues did not adversely affect herbicide efficacy. Without residual herbicides, early-season weed density was often higher following the late-terminated cover crop compared with other termination treatments, though midseason weed density was typically lower. When termination treatment affected final weed biomass, it was lower following late termination, with one exception—crop establishment was reduced at 1 site-year, leading to reduced weed–crop competition and greater weed biomass. Our results suggest that growers can use mixtures and, if well-timed to a rainfall event for incorporation, still effectively use soil-residual herbicides to maintain adequate weed control in tobacco regardless of how the cover crop is managed. Later termination, resulting in more residue, may lead to less weed biomass accumulation in the absence of herbicide use.

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Efficacy and economics of integrated weed management in groundnut (Arachis hypogea L.)

Acta agriculturae Slovenica ◽

10.14720/aas.2020.116.1.1602 ◽

2020 ◽

Vol 116 (1) ◽

pp. 137

Author(s):

Oludamilola ADEMABAYOJE ◽

Joseph ADIGUN ◽

Olusegun ADEYEMI ◽

Olumide DARAMOLA ◽

Godwin AJIBOYE

Keyword(s):

Weed Management ◽

Field Experiments ◽

Cost Benefit ◽

Integrated Weed Management ◽

Gross Margin ◽

Subsequent Increase ◽

Early Season ◽

Arachis Hypogea ◽

Pod Yield ◽

Cost Benefit Ratio

Weed management is an important and expensive step in groundnut production. Field experiments were conducted in the early and late wet seasons of 2017 to evaluate the effectiveness and profitability of weed management using hoe weeding, herbicides or their combination in groundnut production. Butachlor and propaben at 2.0 kg a.i (active ingredient) ha-1 each followed by (fb) supplementary hoe-weeding (shw) at 6 weeks after sowing (WAS) significantly reduced weed cover and biomass with subsequent increase in groundnut pod yield similar to hoe-weeding treatments and better than either herbicide applied alone. The highest groundnut pod yield (1485.7 kg ha-1) and revenue ($1639.2) in the early season was obtained with three hoe weeding passes. However, in the late season, the highest groundnut pod yield (1146.3 kg ha-1) was obtained with propaben plus hoe-weeding and the highest revenue ($1264.8) obtained with butachlor plus hoe-weeding. Although three hoe-weedings gave the highest revenue in the early season, the gross margin and cost-benefit ratio obtained with hoe weeding treatments was lower than those of herbicides fb shw. This study showed that integrated weed management with butachlor or propaben and fb shw will improve weed control, productivity and profitability of groundnut production. Multiple hoe weeding, however, did not guarantee the highest profit but rather increased the cost of production.

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