Herbicide selection to terminate grass, legume, and brassica cover crop species

AbstractCover crops provide a number of agronomic benefits, including weed suppression, which is important as cases of herbicide resistance continue to rise. To effectively suppress weeds, high cover crop biomass is needed, which necessitates later termination timing. Cover crop termination is important to mitigate potential planting issues and prevent surviving cover crop competition with cash crops. Field studies were conducted in Virginia to determine the most effective herbicide options alone or combined with glyphosate or paraquat to terminate a range of cover crop species. Results revealed that grass cover crop species were controlled (94% to 98%) by glyphosate alone 4 wk after application (WAA). Overall, legume species varied in response to the single active-ingredient treatments, and control increased with the addition of glyphosate or paraquat. Mixes with glyphosate provided better control of crimson clover and hairy vetch by 7% to 8% compared with mixes containing paraquat 4 WAA. Mix partner did not influence control of Austrian winter pea. No treatment adequately controlled rapeseed in this study, with a maximum of 58% control observed with single active-ingredient treatments and 62% control with mixes. Height reduction for all cover crop species supports visible rating data. Rapeseed should be terminated when smaller, which could negate weed suppressive benefits from this cover crop species. Growers should consider herbicide selection and termination timing in their cover crop plan to ensure effective termination.

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A method for mechanically killing cover crops to optimize weed suppression

American Journal of Alternative Agriculture ◽

10.1017/s0889189300006408 ◽

1995 ◽

Vol 10 (4) ◽

pp. 157-162 ◽

Cited By ~ 27

Author(s):

N.G. Creamer ◽

B. Plassman ◽

M.A. Bennett ◽

R.K. Wood ◽

B.R. Stinner ◽

...

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Crop Residues ◽

Subterranean Clover ◽

Soil Surface ◽

Weed Suppression ◽

Hairy Vetch ◽

Mechanical Method ◽

Crop Species ◽

Crimson Clover

AbstractResidues of dead cover crops can suppress weeds by providing a mulch on the soil surface. The cover crop usually is killed with herbicides, but a mechanical method is desirable in systems intended to reduce chemical use. We designed and built an undercutter to kill cover crops by severing their roots while flattening the intact aboveground biomass on the surface of raised beds. We studied which cover crop species could be killed with the undercutter and compared the weed control potential of cover crop residues after flail mowing, sicklebar mowing, and undercutting.Whether a species was killed by the undercutter depended primarily on growth stage. Species that were in mid- to late bloom or beyond, including rye, hairy vetch, bigflower vetch, crimson clover, barley, and subterranean clover, were easily killed by undercutting. There were no differences in dry weights of broadleaf weeds between the undercut and simulated sicklebar mowed treatments, both of which had less weed biomass than the clean-tilled or flail-mowed plots.

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Influence of legume cover crops and conservation tillage on soil populations of selected fungal genera

Canadian Journal of Microbiology ◽

10.1139/m88-038 ◽

1988 ◽

Vol 34 (3) ◽

pp. 201-206 ◽

Cited By ~ 9

Author(s):

C. S. Rothrock ◽

W. L. Hargrove

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Conservation Tillage ◽

Field Studies ◽

Macrophomina Phaseolina ◽

Hairy Vetch ◽

Fusarium Spp ◽

Crimson Clover ◽

Legume Cover Crops ◽

Legume Cover Crop

The influence of winter legume cover crops and of tillage on soil populations of fungal genera containing plant pathogenic species in the subsequent summer sorghum crop were examined in field studies. Legume cover crops significantly increased populations of Pythium spp. throughout the sorghum crop compared with a rye cover crop or no cover crop. This stimulation of the populations of Pythium spp. was not solely due to colonization of cover-crop residue, as populations were significantly greater at the time the legume cover crop was desiccated. Removal of aboveground residue generally decreased populations of Pythium spp. in soil. Incorporation of residue by tillage increased populations of Pythium spp. at some sampling dates. Legumes differed in the magnitude of stimulation, with hairy vetch stimulating Pythium spp. more than crimson clover. Cover crop treatments did not consistently influence soil populations of Fusarium spp., Rhizoctonia solani, Rhizoctonia-like binucleate fungi, or Macrophomina phaseolina. Macrophomina phaseolina populations were significantly greater under no tillage.

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Carryover of Common Corn and Soybean Herbicides to Various Cover Crop Species

Weed Technology ◽

10.1614/wt-d-16-00062.1 ◽

2017 ◽

Vol 31 (1) ◽

pp. 21-31 ◽

Cited By ~ 19

Author(s):

Cody D. Cornelius ◽

Kevin W. Bradley

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Production Systems ◽

Italian Ryegrass ◽

Hairy Vetch ◽

Crop Species ◽

Cereal Rye ◽

Crimson Clover ◽

Crop Establishment ◽

Biomass Reduction

The recent interest in cover crops as component of Midwest corn and soybean production systems has led to the need for additional research, including the effects of residual corn and soybean herbicide treatments on fall cover crop establishment. Field studies were conducted in 2013, 2014, and 2015 in Columbia, Missouri to investigate the effects of common residual herbicides applied in corn and soybean on establishment of winter wheat, tillage radish, cereal rye, crimson clover, winter oat, Austrian winter pea, Italian ryegrass, and hairy vetch. Cover crops were evaluated for stand and biomass reduction 28 d after emergence (DAE). Rainfall from herbicide application to cover crop seeding date was much greater in 2014 and 2015, which resulted in less carryover in these years compared to 2013. When averaged across all herbicides evaluated in these experiments, the general order of sensitivity of cover crops to herbicide carryover, from greatest to least was Austrian winter pea=crimson clover>oilseed radish>Italian ryegrass>hairy vetch>wheat >winter oat>cereal rye. Cereal rye had the fewest instances of biomass or stand reduction with only four out of the 27 herbicides adversely effecting establishment. Pyroxasulfone consistently reduced Italian ryegrass and winter oat biomass at least 67% in both the corn and soybean experiments. In the soybean experiment, imazethapyr- and fomesafen-containing products resulted in severe stand and biomass reduction in both years while flumetsulam-containing products resulted in the greatest carryover symptoms in the corn experiment. Results from these experiments suggest that several commonly used corn and soybean herbicides have the potential to hinder cover crop establishment, but the severity of damage will depend on weather, cover crop species, and the specific herbicide combination.

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Comparison of Mixtures vs. Monocultures of Cover Crops for Fresh-market Tomato Production With and Without Herbicide

HortScience ◽

10.21273/hortsci.33.7.1163 ◽

1998 ◽

Vol 33 (7) ◽

pp. 1163-1166 ◽

Cited By ~ 43

Author(s):

John R. Teasdale ◽

Aref A. Abdul-Baki

Keyword(s):

Cover Crops ◽

Cover Crop ◽

C:N Ratio ◽

Weed Suppression ◽

Hairy Vetch ◽

Fresh Market ◽

Vicia Villosa ◽

Tomato Production ◽

Crimson Clover ◽

Marketable Fruit

Hairy vetch (Vicia villosa Roth), crimson clover (Trifolium incarnatum L.), and rye (Secale cereale L.) and mixtures of rye with hairy vetch and/or crimson clover were compared for no-tillage production of staked, fresh-market tomatoes (Lycopersicon esculentum Mill.) on raised beds. All cover crops were evaluated both with or without a postemergence application of metribuzin for weed control. Biomass of cover crop mixtures were higher than that of the hairy vetch monocrop. Cover crop nitrogen content varied little among legume monocrops and all mixtures but was lower in the rye monocrop. The C:N ratio of legume monocrops and all mixtures was <30 but that of the rye monocrop was >50, suggesting that nitrogen immobilization probably occurred only in the rye monocrop. Marketable fruit yield was similar in the legume monocrops and all mixtures but was lower in the rye monocrop when weeds were controlled by metribuzin. When no herbicide was applied, cover crop mixtures reduced weed emergence and biomass compared to the legume monocrops. Despite weed suppression by cover crop mixtures, tomatoes grown in the mixtures without herbicide yielded lower than the corresponding treatments with herbicide in 2 of 3 years. Chemical name used: [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one](metribuzin).

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Weed Control and Sweet Corn (Zea maysvar.rugosa) Response in a No-till System with Cover Crops

Weed Science ◽

10.1017/s0043174500094005 ◽

1996 ◽

Vol 44 (2) ◽

pp. 355-361 ◽

Cited By ~ 50

Author(s):

Nilda R. Burgos ◽

Ronald E. Talbert

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Sweet Corn ◽

Weed Suppression ◽

Growth And Yield ◽

Hairy Vetch ◽

Yellow Nutsedge ◽

No Till ◽

Agricultural Experiment ◽

And Control

Studies were conducted at the Main Agricultural Experiment Station in Fayetteville and the Vegetable Substation in Kibler, Arkansas, in 1992 and 1993 on the same plots to evaluate weed suppression by winter cover crops alone or in combination with reduced herbicide rates in no-till sweet corn and to evaluate cover crop effects on growth and yield of sweet corn. Plots seeded to rye plus hairy vetch, rye, or wheat had at least 50% fewer early season weeds than hairy vetch alone or no cover crop. None of the cover crops reduced population of yellow nutsedge. Without herbicides, hairy vetch did not suppress weeds 8 wk after cover crop desiccation. Half rates of atrazine and metolachlor (1.1 + 1.1 kg ai ha−1) reduced total weed density more effectively in no cover crop than in hairy vetch. Half rates of atrazine and metolachlor controlled redroot pigweed, Palmer amaranth, and goosegrass regardless of cover crop. Full rates of atrazine and metolachlor (2.2 + 2.2 kg ai ha−1) were needed to control large crabgrass in hairy vetch. Control of yellow nutsedge in hairy vetch was marginal even with full herbicide rates. Yellow nutsedge population increased and control with herbicides declined the second year, particularly with half rates of atrazine and metolachlor. All cover crops except hairy vetch alone reduced emergence, height, and yield of sweet corn. Sweet corn yields from half rates of atrazine and metolachlor equalled the full rates regardless of cover crops.

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Preplant-Postemergence Herbicides for Legume Cover-Crop Control in Minimum Tillage Systems

Weed Technology ◽

10.1017/s0890037x00025495 ◽

1990 ◽

Vol 4 (2) ◽

pp. 332-336 ◽

Cited By ~ 13

Author(s):

James L. Griffin ◽

Seth M. Dabney

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Subterranean Clover ◽

Field Studies ◽

Application Time ◽

Hairy Vetch ◽

Crimson Clover ◽

Legume Cover Crops ◽

Legume Cover Crop ◽

Postemergence Herbicides

Field studies were conducted to compare preplant-postemergence-applied paraquat, glyphosate, SC-0224, and HOE-39866 on subterranean clover, crimson clover, and hairy vetch cover crops. Subterranean clover control with paraquat at 1.1 kg ai/ha was about 80 and 100% when applied in early April and early May, respectively, regardless of spray volume (190 vs. 370 L/ha). Glyphosate and SC-0224 at 1.7 and 2.8 kg ai/ha applied in April controlled about 53% of subterranean clover. Subterranean clover control with HOE-39866 at 0.8 kg ai/ha applied in April was excellent. Paraquat at 0.6 kg ai/ha and HOE-39866 at 0.8 kg/ha regardless of application time controlled both crimson clover and hairy vetch. Grain sorghum and soybean yields following the legume cover crops generally were similar for the herbicide treatments.

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Cultivation and Interseeding for Weed Control in Transplanted Cabbage

Weed Technology ◽

10.1614/wt-03-157r ◽

2004 ◽

Vol 18 (3) ◽

pp. 704-710 ◽

Cited By ~ 11

Author(s):

Daniel C. Brainard ◽

Robin R. Bellinder ◽

Andrew J. Miller

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Field Trials ◽

Integrated System ◽

Weed Suppression ◽

Yield Losses ◽

Hairy Vetch ◽

Crop Species ◽

Yield Penalty ◽

Additional Nitrogen

Multiple means of overcoming interspecific competition between transplanted cabbage and interseeded cover crops were studied in field trials conducted from 1995 to 2001. Cover crop species and time of seeding (1995 and 1996), use of supplemental nitrogen (1997 and 1998), and herbicide regulation (1999 and 2001) were evaluated with the objective of integrating soil-improving cover crops into cabbage production while facilitating weed suppression with minimal use of herbicides. Cabbage was cultivated at 10, 10 + 20, or 10 + 20 + 30 d after transplanting (DAT) with or without cover crops (hairy vetch, lana vetch, or oats) sown at the time of the last cultivation. Early interseeding (10 DAT) of all species significantly reduced cabbage yields. Both vetches could be sown 20 or 30 DAT without a yield penalty. However, weed suppression was not consistently greater than cultivation without cover crops. Spring oats were unacceptably competitive, even when sown 30 DAT in some years. With additional nitrogen, cabbage yields were consistently increased, but the increases were not directly related to decreased competition from either weeds or cover crops. The potential for herbicide regulation of cover crops to prevent cabbage yield losses could not be evaluated because cabbage yields were not reduced by cover crops in 1999 and 2001. Although interseeded crops did not generally provide significant in-season weed suppression compared with cultivation alone, the lack of yield penalty and the potential soil-improving qualities of legumes may justify interseeding hairy vetch at 20 DAT in an integrated system.

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Allelopathic Impact of Cover Crop Species on Soybean and Goosegrass Seedling Germination and Early Growth

Agriculture ◽

10.3390/agriculture11100965 ◽

2021 ◽

Vol 11 (10) ◽

pp. 965

Author(s):

Kendall Sheldon ◽

Sam Purdom ◽

Avat Shekoofa ◽

Larry Steckel ◽

Virginia Sykes

Keyword(s):

Cover Crops ◽

Root Length ◽

Cover Crop ◽

Deionized Water ◽

Weed Suppression ◽

Crop Species ◽

Allelopathic Potential ◽

Row Crops ◽

Crimson Clover ◽

Seedling Root

Cover crops can provide a variety of benefits to an agricultural system: weed suppression, soil quality improvement, and soil water infiltration. Although there is ample research documenting weed suppression from cover crops, the mechanics of the suppression are not implicitly understood. Along with the aforementioned positive attributes, negative allelopathic effects on row crops planted into cover crop systems have been documented. The objective of this study was to evaluate the allelopathic potential of certain cover crop species on soybean (Glycine max L.) and goosegrass (Eleusine indica L.) germination and early seedling growth under controlled environments in petri dish and pot experiments. Leachates from above-ground biomass of five cover crop species, wheat (Triticum aestivum L.), cereal rye (Secale cereale), hairy vetch (Vicia villosa), crimson clover (Trifolium incarnatum L.), and canola (Brassica napus L.), from two locations (East and Middle Tennessee) were extracted and applied at 0 (water) and 50 v/v. In experiment I, both soybean and goosegrass seeds were examined, and, in experiment II, only soybean seeds were examined under the application of cover crop leachates. Most cover crop leachates from both locations significantly reduced the soybean seedling root length (p < 0.01). Overall, the application of canola extract (East Tennessee) suppressed soybean seed germination the most (28%) compared to deionized water. For goosegrass, the wheat cover crop leachate significantly reduced seedling root length (p < 0.01). In experiment II, the soybean root nodulation was significantly increased with the wheat extract treatment compared to deionized water. While the results indicate that the location and environment may change cover crop species allelopathic potential, the wheat cover crop leachate had the most potent allelopathic impact on goosegrass germination and growth; however, had the lowest observed adverse effect on our tested row crop, soybean.

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Response of broadleaf and grass cover crop species to soil residues of glyphosate and aminomethylphosphonic acid (AMPA)

Weed Technology ◽

10.1017/wet.2021.77 ◽

2021 ◽

pp. 1-25

Author(s):

Zahoor A. Ganie ◽

Amit J. Jhala

Keyword(s):

Seed Germination ◽

Cover Crops ◽

Cover Crop ◽

Hairy Vetch ◽

Crop Species ◽

Cereal Rye ◽

Crimson Clover ◽

Aminomethylphosphonic Acid ◽

Loam Soil ◽

The Impact

Abstract Glyphosate is the most widely used herbicide in the United States; however, concern about increasing residues of glyphosate and its metabolite aminomethylphosphonic acid (AMPA) in soil is escalating. There is a lack of scientific literature examining the response of cover crops to soil residues of glyphosate or AMPA. The objectives of this study were to evaluate the impact of glyphosate or AMPA residues in silty clay loam soil on emergence, growth, and biomass of cover crops, including cereal rye, crimson clover, field pea, hairy vetch, and winter wheat, as well as their germination in a 0.07% (0.7 g/L) solution of AMPA or glyphosate. Greenhouse studies were conducted at the University of Nebraska-Lincoln to determine the dose response of broadleaf and grass cover crops to soil-applied glyphosate or AMPA. The results indicated that soil treated with glyphosate or AMPA up to 105 mg ae kg–1 of soil had no effect on the emergence, growth, above-ground biomass, and root biomass of any of the cover crop species tested. To evaluate the impact of AMPA or glyphosate on the seed germination of cover crop species, seeds were soaked in petri plates filled with a 0.7 g L−1 solution of AMPA or glyphosate. There was no effect of AMPA on seed germination of any of the cover crop species tested. Seed germination of crimson clover and field pea in a 0.7 g L−1 solution of glyphosate was comparable to the nontreated control; however, the germination of cereal rye, hairy vetch, and winter wheat was reduced by 48%, 75%, and 66%, respectively, compared to the nontreated control. The results suggested that glyphosate or AMPA up to 105 mg ae kg–1 in silt clay loam soil is unlikely to cause any negative effect on the evaluated cover crop species.

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Herbicide carryover to various fall-planted cover crop species

Weed Technology ◽

10.1017/wet.2019.79 ◽

2019 ◽

Vol 34 (1) ◽

pp. 25-34

Author(s):

Lucas S. Rector ◽

Kara B. Pittman ◽

Shawn C. Beam ◽

Kevin W. Bamber ◽

Charles W. Cahoon ◽

...

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Field Studies ◽

Grass Cover ◽

Crop Species ◽

Visible Injury ◽

Cereal Rye ◽

Crimson Clover ◽

Crop Planting ◽

Crop Biomass

AbstractResidual herbicides applied to summer cash crops have the potential to injure subsequent winter annual cover crops, yet little information is available to guide growers’ choices. Field studies were conducted in 2016 and 2017 in Blacksburg and Suffolk, Virginia, to determine carryover of 30 herbicides commonly used in corn, soybean, or cotton on wheat, barley, cereal rye, oats, annual ryegrass, forage radish, Austrian winter pea, crimson clover, hairy vetch, and rapeseed cover crops. Herbicides were applied to bare ground either 14 wk before cover crop planting for a PRE timing or 10 wk for a POST timing. Visible injury was recorded 3 and 6 wk after planting (WAP), and cover crop biomass was collected 6 WAP. There were no differences observed in cover crop biomass among herbicide treatments, despite visible injury that suggested some residual herbicides have the potential to effect cover crop establishment. Visible injury on grass cover crop species did not exceed 20% from any herbicide. Fomesafen resulted in the greatest injury recorded on forage radish, with greater than 50% injury in 1 site-year. Trifloxysulfuron and atrazine resulted in greater than 20% visible injury on forage radish. Trifloxysulfuron resulted in the greatest injury (30%) observed on crimson clover in 1 site-year. Prosulfuron and isoxaflutole significantly injured rapeseed (17% to 21%). Results indicate that commonly used residual herbicides applied in the previous cash crop growing season result in little injury on grass cover crop species, and only a few residual herbicides could potentially affect the establishment of a forage radish, crimson clover, or rapeseed cover crop.

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