Crop Species Diversity Affects Productivity and Weed Suppression in Perennial Polycultures under Two Management Strategies

Adoption of cover crops has the potential to increase agricultural sustainability in the US and beyond. In 2017, a survey was conducted with Nebraska stakeholders in an attempt to evaluate current cover crop management strategies adopted in soybean (Glycine max [L.] Merr.), field corn (Zea mays L.), and seed corn production. Eighty-two Nebraska stakeholders answered the survey, of which 80% identified themselves as growers. Eighty-seven percent of respondents manage cover crops, and the average cover crop ha planted on a per farm basis is 32%. The primary method of establishing cover crops following soybeans and field corn is drilling. In seed corn, interseeding is the main seeding strategy for cover crop establishment. Cereal rye (Secale cereale L.) appeared as the most adopted cover crop species (either alone or in mixtures with radish [Raphanus sativus L.] or hairy vetch [Vicia villosa Roth]). Over 95% of respondents utilize herbicides for cover crop termination in the spring before crop planting. Glyphosate is used by 100% of survey respondents that use herbicides for cover crop termination. The major observed impacts of incorporating cover crops into a production system according to survey respondents are reduced soil erosion and weed suppression. According to 93% of respondents, cover crops improve weed control by suppressing winter and/or summer annual weed species. The biggest challenge reported by cover crop adopters is planting and establishing a decent stand before winter. According to the results of this survey, there are different management strategies, positive outcomes, and challenges that accompany cover crop adoption in Nebraska. These results will help growers, agronomists, and researchers better guide cover crop adoption, management, and future research and education needs in Nebraska and beyond.

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Spring-planted cover crops for weed control in soybean

Renewable Agriculture and Food Systems ◽

10.1017/s1742170521000107 ◽

2021 ◽

pp. 1-8

Author(s):

Katja Koehler-Cole ◽

Christopher A. Proctor ◽

Roger W. Elmore ◽

David A. Wedin

Keyword(s):

Weed Control ◽

Biomass Production ◽

Cover Crops ◽

Weed Management ◽

Block Design ◽

Weed Suppression ◽

Crop Species ◽

Cold Temperatures ◽

Weed Biomass ◽

Small Grains

Abstract Replacing tillage with cover crops (CC) for weed management in corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] systems with mechanical weed control has many soil health benefits but in the western Corn Belt, CC establishment after harvest is hampered by cold temperatures, limited labor and few compatible CC species. Spring-planted CC may be an alternative, but information is lacking on suitable CC species. Our objective was to evaluate four spring-planted CC with respect to biomass production and weed suppression, concurrent with CC growth and post-termination. Cover crop species tested were oat (Avena sativa L.), barley (Hordeum vulgare L.), brown mustard [Brassica juncea (L.) Czern.] and yellow mustard (Brassica hirta Moench). They were compared to no-CC treatments that were either tilled pre- and post-planting of soybean (no-CC tilled) or not tilled at all (no-CC weedy). CC were planted in late March to early April, terminated 52–59 days later using an undercutter, and soybean was planted within a week. The experiment had a randomized complete block design with four replications and was repeated for 3 years. Mustards and small grains produced similar amounts of biomass (1.54 Mg ha−1) but mustard biomass production was more consistent (0.85–2.72 Mg ha−1) than that of the small grains (0.35–3.81 Mg ha−1). Relative to the no-CC weedy treatment, mustards suppressed concurrent weed biomass in two out of 3 years, by 31–97%, and small grains suppressed concurrent weed biomass in only 1 year, by 98%. Six weeks after soybean planting, small grains suppressed weed biomass in one out of 3 years, by 79% relative to the no-CC weedy treatment, but mustards did not provide significant weed suppression. The no-CC tilled treatment suppressed weeds each year relative to the no-CC weedy treatment, on average 87%. The ineffective weed control by CC reduced soybean biomass by about 50% six weeks after planting. While spring-planted CC have the potential for pre-plant weed control, they do not provide adequate early season weed suppression for soybean.

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Functional Diversity: An Epistemic Roadmap

BioScience ◽

10.1093/biosci/biz089 ◽

2019 ◽

Vol 69 (10) ◽

pp. 800-811 ◽

Cited By ~ 3

Author(s):

Christophe Malaterre ◽

Antoine C Dussault ◽

Sophia Rousseau-Mermans ◽

Gillian Barker ◽

Beatrix E Beisner ◽

...

Keyword(s):

Species Diversity ◽

Functional Diversity ◽

Functional Traits ◽

Management Strategies ◽

Taxonomic Diversity ◽

Ecological Management ◽

Diversity Studies

Abstract Functional diversity holds the promise of understanding ecosystems in ways unattainable by taxonomic diversity studies. Underlying this promise is the intuition that investigating the diversity of what organisms actually do (i.e., their functional traits) within ecosystems will generate more reliable insights into the ways these ecosystems behave, compared to considering only species diversity. But this promise also rests on several conceptual and methodological (i.e., epistemic) assumptions that cut across various theories and domains of ecology. These assumptions should be clearly addressed, notably for the sake of an effective comparison and integration across domains, and for assessing whether or not to use functional diversity approaches for developing ecological management strategies. The objective of this contribution is to identify and critically analyze the most salient of these assumptions. To this aim, we provide an epistemic roadmap that pinpoints these assumptions along a set of historical, conceptual, empirical, theoretical, and normative dimensions.

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Comparison of Conventional and Alternative Nursery Weed Management Strategies

Weed Technology ◽

10.1017/s0890037x00024179 ◽

1995 ◽

Vol 9 (4) ◽

pp. 761-767 ◽

Cited By ~ 2

Author(s):

James B. Calkins ◽

Bert T. Swanson

Keyword(s):

Weed Management ◽

Cover Crop ◽

Production Systems ◽

Management Strategies ◽

Life Cycles ◽

Weed Suppression ◽

Winter Rye ◽

Field Management ◽

Companion Crop ◽

Herbicide Management

Soil cultivation (3 to 5 times/yr) and herbicide management (oxadiazon, 3.92 kg ai/ha), agricultural standards for reducing weed competition, were compared to three alternative nursery field management systems regarding weed suppression: ‘Norcen’ bird's-foot trefoil companion crop, ‘Wheeler’ winter rye cover crop/mulch, and grass sod (80% ‘Eton’ perennial ryegrass and 20% ‘Ruby’ red fescue). Field management treatment had a significant effect on observed weed populations. Weed densities were also subject to yearly variations caused by climate and endogenous weed life cycles. Herbicide management (oxadiazon) consistently provided the best control of undesired vegetation (0.3 weeds/m2) followed by the grass sod (0.7 weeds/m2), Wheeler rye cover crop/mulch (1.7 weeds/m2), Norcen bird's-foot trefoil companion crop (8.6 weeds/m2), and cultivated (55.7 weeds/m2) treatments, respectively. Although the grass sod treatment provided excellent control of undesired vegetation, as an alternative to cultivation and herbicide use, it proved to be excessively competitive with the nursery crop. The bird's-foot trefoil treatment quickly became infested with broadleaf weeds the eradication of which proved difficult. The Wheeler winter rye cover crop/mulch field management system provided acceptable weed control combined with other beneficial effects on the plant/soil environment. Results support the effectiveness of Wheeler winter rye and perhaps other allelopathic cover crop/mulch systems in controlling undesired vegetation in horticultural field production systems.

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

Weed Technology ◽

10.1017/wet.2019.107 ◽

2019 ◽

Vol 34 (1) ◽

pp. 48-54

Author(s):

Kara B. Pittman ◽

Charles W. Cahoon ◽

Kevin W. Bamber ◽

Lucas S. Rector ◽

Michael L. Flessner

Keyword(s):

Active Ingredient ◽

Cover Crops ◽

Cover Crop ◽

Field Studies ◽

Weed Suppression ◽

Hairy Vetch ◽

Crop Species ◽

Rating Data ◽

Crimson Clover ◽

And Control

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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Food Security: Crop Species Diversity

Science ◽

10.1126/science.328.5975.169-e ◽

2010 ◽

Vol 328 (5975) ◽

pp. 169-170 ◽

Cited By ~ 11

Author(s):

H. Dempewolf ◽

P. Bordoni ◽

L. H. Rieseberg ◽

J. M. M. Engels

Keyword(s):

Food Security ◽

Species Diversity ◽

Crop Species

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Correlations of phytoplankton standing crop, species diversity and dominance with physical-chemical data in a coastal salt pond

Hydrobiologia ◽

10.1007/bf00020524 ◽

1979 ◽

Vol 64 (3) ◽

pp. 233-237 ◽

Cited By ~ 4

Author(s):

William B. Samuels ◽

Anthony Uzzo ◽

Robert Nuzzi

Keyword(s):

Species Diversity ◽

Standing Crop ◽

Chemical Data ◽

Crop Species ◽

Salt Pond ◽

Physical Chemical

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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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Does Crop Species Diversity Influence Soil Carbon and Nitrogen Pools?

Agronomy Journal ◽

10.2134/agronj2015.0316 ◽

2016 ◽

Vol 108 (1) ◽

pp. 427-432 ◽

Cited By ~ 5

Author(s):

Amitava Chatterjee ◽

Kelly Cooper ◽

Aaron Klaustermeier ◽

R. Awale ◽

Larry J. Cihacek

Keyword(s):

Species Diversity ◽

Soil Carbon ◽

Crop Species ◽

Carbon And Nitrogen ◽

Soil Carbon And Nitrogen ◽

Nitrogen Pools

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Weed Suppression in Cover Crop Monocultures and Mixtures

Weed Science ◽

10.1017/wsc.2017.59 ◽

2017 ◽

Vol 66 (1) ◽

pp. 121-133 ◽

Cited By ~ 36

Author(s):

Barbara Baraibar ◽

Mitchell C. Hunter ◽

Meagan E. Schipanski ◽

Abbe Hamilton ◽

David A. Mortensen

Keyword(s):

Ecosystem Services ◽

Cover Crops ◽

Cover Crop ◽

Biomass Accumulation ◽

Weed Suppression ◽

Species Selection ◽

Grass Species ◽

Weed Seed ◽

Crop Species ◽

Cereal Rye

Interest in planting mixtures of cover crop species has grown in recent years as farmers seek to increase the breadth of ecosystem services cover crops provide. As part of a multidisciplinary project, we quantified the degree to which monocultures and mixtures of cover crops suppress weeds during the fall-to-spring cover crop growing period. Weed-suppressive cover crop stands can limit weed seed rain from summer- and winter-annual species, reducing weed population growth and ultimately weed pressure in future cash crop stands. We established monocultures and mixtures of two legumes (medium red clover and Austrian winter pea), two grasses (cereal rye and oats), and two brassicas (forage radish and canola) in a long fall growing window following winter wheat harvest and in a shorter window following silage corn harvest. In fall of the long window, grass cover crops and mixtures were the most weed suppressive, whereas legume cover crops were the least weed suppressive. All mixtures also effectively suppressed weeds. This was likely primarily due to the presence of fast-growing grass species, which were effective even when they were seeded at only 20% of their monoculture rate. In spring, weed biomass was low in all treatments due to winter kill of summer-annual weeds and low germination of winter annuals. In the short window following silage corn, biomass accumulation by cover crops and weeds in the fall was more than an order of magnitude lower than in the longer window. However, there was substantial weed seed production in the spring in all treatments not containing cereal rye (monoculture or mixture). Our results suggest that cover crop mixtures require only low seeding rates of aggressive grass species to provide weed suppression. This creates an opportunity for other species to deliver additional ecosystem services, though careful species selection may be required to maintain mixture diversity and avoid dominance of winter-hardy cover crop grasses in the spring.

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