Weeds in Cover Crops: Context and Management Considerations

Cover crops are increasingly being adopted to provide multiple ecosystem services such as improving soil health, managing nutrients, and decreasing soil erosion. It is not uncommon for weeds to emerge in and become a part of a cover crop plant community. Since the role of cover cropping is to supplement ecosystem service provisioning, we were interested in assessing the impacts of weeds on such provisioning. To our knowledge, no research has examined how weeds in cover crops may impact the provision of ecosystem services and disservices. Here, we review services and disservices associated with weeds in annual agroecosystems and present two case studies from the United States to illustrate how weeds growing in fall-planted cover crops can provide ground cover, decrease potential soil losses, and effectively manage nitrogen. We argue that in certain circumstances, weeds in cover crops can enhance ecosystem service provisioning. In other circumstances, such as in the case of herbicide-resistant weeds, cover crops should be managed to limit weed biomass and fecundity. Based on our case studies and review of the current literature, we conclude that the extent to which weeds should be allowed to grow in a cover crop is largely context-dependent.

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Economic Impacts of Cover Crops for a Missouri Wheat–Corn–Soybean Rotation

Agriculture ◽

10.3390/agriculture9040083 ◽

2019 ◽

Vol 9 (4) ◽

pp. 83 ◽

Cited By ~ 1

Author(s):

Zhen Cai ◽

Ranjith P. Udawatta ◽

Clark J. Gantzer ◽

Shibu Jose ◽

Larry Godsey ◽

...

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Ground Cover ◽

The United States ◽

Biological Properties ◽

Control Group ◽

Soil Productivity ◽

Cost Share ◽

Cash Crop ◽

The Cost

In the United States, agricultural production using row-crop farming has reduced crop diversity. Repeated growing of the same crop in a field reduces soil productivity and increases pests, disease infestations, and weed growth. These negative effects can be mitigated by rotating cash crops with cover crops. Cover crops can improve soil’s physical, chemical, and biological properties, provide ground cover, and sequester soil carbon. This study examines the economic profitability for a four-year wheat–corn–soybean study with cover crops by conducting a field experiment involving a control (without cover crops) at the Soil Health Farm in Chariton County, MO, USA. Our findings suggested that economic profitability of the cash crop is negatively affected by the cover crop during the first two years but were positive in the fourth year. The rotation with cover crops obtained the same profit as in the control group if revenue from the cash crop increased by 35% or the cost of the cover crop decreased by 26% in the first year, depending on the cost of seeding the cover crop and terminating it. This study provides insights for policymakers on ways to improve the economic efficiency of cost-share conservation programs.

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Cover Cropping: A Malleable Solution for Sustainable Agriculture? Meta-Analysis of Ecosystem Service Frameworks in Perennial Systems

Agronomy ◽

10.3390/agronomy11050862 ◽

2021 ◽

Vol 11 (5) ◽

pp. 862

Author(s):

Cynthia M. Crézé ◽

William R. Horwath

Keyword(s):

Ecosystem Services ◽

Sustainable Agriculture ◽

Cover Crops ◽

Ecosystem Service ◽

Cover Crop ◽

Meta Analysis ◽

Value Systems ◽

Perennial Crop ◽

Cover Cropping ◽

Crop Types

Cover crops have been touted for their capacity to enhance multifunctionality and ecosystem services (ESs). Ecosystem services are benefits which people obtain from ecosystems. Despite nearly a century of cover crop research, there has been low adoption of the practice in perennial systems of many parts of the world. Emphasis on the multi-functional dimension of cover crop outcomes may misrepresent the practice as a panacea for sustainable agriculture and distract from the need to tailor the practice to specific contexts and differing value systems. In this study, we explore how cover crop ecosystem service (ES) frameworks reflect the distinct environmental realities of perennial agriculture. We considered that ES value systems are manifested through the non-randomization of research coverage. Therefore, value systems can be elucidated through evidence-based systematic mapping. Our analysis revealed differential systems of ES valuation specific to perennial crop types. While ES frameworks are heavily contextualized, the design of seed mixes is not. We suggest that cover crop adoption could be enhanced by clearly acknowledging the different conceptualizations of agricultural sustainability addressed by various cover crops. Furthermore, explicitly delineating the competing desires of stakeholders is a crucial step in rationally selecting between various cover crop seed mix options.

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Exploring the Use of Ecosystem Services Conceptual Models to Account for the Benefits of Public Lands: An Example from National Forest Planning in the United States

Forests ◽

10.3390/f12030267 ◽

2021 ◽

Vol 12 (3) ◽

pp. 267

Author(s):

Lydia Olander ◽

Katie Warnell ◽

Travis Warziniack ◽

Zoe Ghali ◽

Chris Miller ◽

...

Keyword(s):

Ecosystem Services ◽

Ecosystem Service ◽

Management Strategies ◽

Public Lands ◽

The United States ◽

Forest Planning ◽

National Forest ◽

Planning Team ◽

National Forest Planning

A shared understanding of the benefits and tradeoffs to people from alternative land management strategies is critical to successful decision-making for managing public lands and fostering shared stewardship. This study describes an approach for identifying and monitoring the types of resource benefits and tradeoffs considered in National Forest planning in the United States under the 2012 Planning Rule and demonstrates the use of tools for conceptualizing the production of ecosystem services and benefits from alternative land management strategies. Efforts to apply these tools through workshops and engagement exercises provide opportunities to explore and highlight measures, indicators, and data sources for characterizing benefits and tradeoffs in collaborative environments involving interdisciplinary planning teams. Conceptual modeling tools are applied to a case study examining the social and economic benefits of recreation on the Ashley National Forest. The case study illustrates how these types of tools facilitate dialog for planning teams to discuss alternatives and key ecosystem service outcomes, create easy to interpret visuals that map details in plans, and provide a basis for selecting ecosystem service (socio-economic) metrics. These metrics can be used to enhance environmental impact analysis, and help satisfy the goals of the National Environmental Policy Act (NEPA), the 2012 Planning Rule, and shared stewardship initiatives. The systematic consideration of ecosystem services outcomes and metrics supported by this approach enhanced dialog between members of the Forest planning team, allowed for a more transparent process in identification of key linkages and outcomes, and identified impacts and outcomes that may not have been apparent to the sociologist who is lacking the resource specific expertise of these participants. As a result, the use of the Ecosystem Service Conceptual Model (ESCM) process may result in reduced time for internal reviews and greater comprehension of anticipated outcomes and impacts of proposed management in the plan revision Environmental Impact Statement amongst the planning team.

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Cover crop effects on horseweed (Erigeron canadensis) density and size inequality at the time of herbicide exposure

Weed Science ◽

10.1017/wsc.2019.3 ◽

2019 ◽

Vol 67 (3) ◽

pp. 327-338 ◽

Cited By ~ 9

Author(s):

John M. Wallace ◽

William S. Curran ◽

David A. Mortensen

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Integrated Weed Management ◽

Crop Response ◽

Herbicide Resistant ◽

No Till ◽

Erigeron Canadensis ◽

Size Inequality ◽

Herbicide Exposure ◽

Response Traits

AbstractProactive integrated weed management (IWM) is critically needed in no-till production to reduce the intensity of selection pressure for herbicide-resistant weeds. Reducing the density of emerged weed populations and the number of larger individuals within the population at the time of herbicide application are two practical management objectives when integrating cover crops as a complementary tactic in herbicide-based production systems. We examined the following demographic questions related to the effects of alternative cover-cropping tactics following small grain harvest on preplant, burndown management of horseweed (Erigeron canadensis L.) in no-till commodity-grain production: (1) Do cover crops differentially affect E. canadensis density and size inequality at the time of herbicide exposure? (2) Which cover crop response traits are drivers of E. canadensis suppression at time of herbicide exposure? Interannual variation in growing conditions (study year) and intra-annual variation in soil fertility (low vs. high nitrogen) were the primary drivers of cover crop response traits and significantly affected E. canadensis density at the time of herbicide exposure. In comparison to the fallow control, cover crop treatments reduced E. canadensis density 52% to 86% at the time of a preplant, burndown application. Cereal rye (Secale cereale L.) alone or in combination with forage radish (Raphanus sativus L.) provided the most consistent E. canadensis suppression. Fall and spring cover crop biomass production was negatively correlated with E. canadensis density at the preplant burndown application timing. Our results also show that winter-hardy cover crops reduce the size inequality of E. canadensis populations at the time of herbicide exposure by reducing the number of large individuals within the population. Finally, we advocate for advancement in our understanding of complementarity between cover crop– and herbicide-based management tactics in no-till systems to facilitate development of proactive, herbicide-resistant management strategies.

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The Perceived Benefits, Challenges, and Environmental Effects of Cover Crop Implementation in South Carolina

Agriculture ◽

10.3390/agriculture10090372 ◽

2020 ◽

Vol 10 (9) ◽

pp. 372

Author(s):

Lucas Clay ◽

Katharine Perkins ◽

Marzieh Motallebi ◽

Alejandro Plastina ◽

Bhupinder Singh Farmaha

Keyword(s):

South Carolina ◽

Cover Crops ◽

Cover Crop ◽

Management Practice ◽

Soil Health ◽

Education Level ◽

Limited Information ◽

Best Management ◽

Row Crop ◽

The Impact

Cover crops are becoming more accepted as a viable best management practice because of their ability to provide important environmental and soil health benefits. Because of these benefits, many land managers are strongly encouraging the use of cover crops. Additionally, there is limited information on farmers′ perceptions of the benefits and challenges of implementing cover crops. Many farmers state that they do not have enough money or time to implement cover crops. In an attempt to gather more data about the adoption rate and perceptions of cover crops in South Carolina, a survey was sent to 3000 row crop farmers across the state. Farmers were asked whether they implement cover crops and their perceptions of the benefits and challenges associated with implementation. Furthermore, questions were asked regarding the impact of row cropping on their environment to gauge farmer′s education level on environmental impacts. Responses showed many people are implementing cover crops; however, there are still differences in perceptions about benefits and challenges between those who are adopting cover crops and those who are not. This research assesses these differences and aims to provide a baseline for focusing cover crop programs to tackle these certain challenges and promote the benefits.

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Do diverse mixtures of cover crop residues alter the soil microbial community and increase soil function?

10.5194/egusphere-egu2020-1499 ◽

2020 ◽

Author(s):

Xin Shu ◽

Yiran Zou ◽

Liz Shaw ◽

Lindsay Todman ◽

Mark Tibbett ◽

...

Keyword(s):

Microbial Community ◽

Soil Respiration ◽

Cover Crops ◽

Soil Microbial Community ◽

Cover Crop ◽

Crop Residues ◽

Soil Health ◽

Soil Function ◽

Soil Microbial ◽

Quaternary Mixture

Cover crops are a contemporary tool to sustainably manage agricultural soils by boosting fertility, suppressing weeds and disease, and benefiting cash crop yields, thus securing future food supply. Due to the different chemical composition of crop residues from different plant families, we hypothesised that a mixture of cover crop residues may have a greater potential to improve soil health than the sum of the parts. Our experiment focused on the impact of four cover crops (clover, sunflower, radish and buckwheat) and their quaternary mixture on soil respiration and the soil microbial community in an 84-day microcosm experiment. On average adding cover crop residues significantly (P < 0.001) increased soil respiration from 29 to 343 &#181;g C g-1 h-1 and microbial biomass from 18 to 60 &#181;g C g-1, compared to the unamended control during 84 days&#8217; incubation. Cover crop addition resulted in a significant (P < 0.001) alteration of the soil microbial community structure compared to that of the control. The quaternary mixture of cover crop residues significantly (P = 0.011) increased soil respiration rate by 23.79 &#181;g C g-1 h-1 during the period 30 to 84 days after residue incorporation, compared to the average of the four individual residues. However, no significant difference in the size of the microbial biomass was found between the mixture and the average of the four individuals, indicating the mixture may invest resources which transit dormant microbial species into a metabolically active state and thus boost microbial respiration. Analysis of similarity of microbial community composition (ANOSIM) demonstrated the mixture significantly (P = 0.001) shifted microbial community structure away from buckwheat (R = 0.847), clover (R = 0.688), radish (R = 0.285) and sunflower (R = 0.785), respectively. This implies cover crop residues provide a niche specialization and differentiation on a selection of microbial communities that favour certain plant compounds. While applying cover crop residues has positive impacts on soil function, we found that applying a mixture of cover crop residues may provide greater potential to select for microorganisms or activate dormant microbial species which result in higher soil function. The outcome of this study will help seed suppliers to design, and farmers to select, novel cover crop mixtures which enhance soil function synergistically, leading to a greater potential to sustainably improve soil health.

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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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Evaluating Cover Crops and Herbicides for Glyphosate-Resistant Palmer Amaranth (Amaranthus palmeri) Control in Cotton

Weed Technology ◽

10.1614/wt-d-15-00113.1 ◽

2016 ◽

Vol 30 (2) ◽

pp. 415-422 ◽

Cited By ~ 18

Author(s):

Matthew S. Wiggins ◽

Robert M. Hayes ◽

Lawrence E. Steckel

Keyword(s):

Cover Crops ◽

Cover Crop ◽

The United States ◽

Palmer Amaranth ◽

Amaranthus Palmeri ◽

Hairy Vetch ◽

Cereal Rye ◽

Crimson Clover ◽

Legume Cover Crops ◽

Herbicide Programs

Glyphosate-resistant (GR) weeds, especially GR Palmer amaranth, are very problematic in cotton-producing areas of the midsouthern region of the United States. Growers rely heavily on PRE residual herbicides to control Palmer amaranth since few effective POST options exist. Interest in integrating high-residue cover crops with existing herbicide programs to combat GR weeds has increased. Research was conducted in 2013 and 2014 in Tennessee to evaluate GR Palmer amaranth control when integrating cover crops and PRE residual herbicides. Cereal rye, crimson clover, hairy vetch, winter wheat, and combinations of one grass plus one legume were compared with winter weeds without a cover crop followed by fluometuron or acetochlor applied PRE. Biomass of cover crops was determined prior to termination 3 wk before planting. Combinations of grass and legume cover crops accumulated the most biomass (> 3,500 kg ha−1) but by 28 d after application (DAA) the cereal rye and wheat provided the best Palmer amaranth control. Crimson clover and hairy vetch treatments had the greatest number of Palmer amaranth. These cereal and legume blends reduced Palmer amaranth emergence by half compared to non–cover-treated areas. Fluometuron and acetochlor controlled Palmer amaranth 95 and 89%, respectively, at 14 DAA and 54 and 62%, respectively, at 28 DAA. Cover crops in combination with a PRE herbicide did not adequately control Palmer amaranth.

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Effects of Organic Fertilization and Cover Crops on an Organic Pepper System

HortTechnology ◽

10.21273/horttech.18.2.215 ◽

2008 ◽

Vol 18 (2) ◽

pp. 215-226 ◽

Cited By ~ 15

Author(s):

K. Delate ◽

C. Cambardella ◽

A. McKern

Keyword(s):

Soil Fertility ◽

Cover Crops ◽

Cover Crop ◽

Crop Production ◽

Large Scale ◽

Soil Analysis ◽

Organic Fertilizer ◽

The United States ◽

Organic Fertilizers ◽

Organic Farm

With the continuing 20% growth rate in the organic industry, organic vegetable crop production has increased to 98,525 acres in the United States. The requirement for certified organic vegetable producers to implement a soil-building plan has led to the development of soil fertility systems based on combinations of organic fertilizers and cover crops. To determine optimal soil fertility combinations, conventional and organic bell pepper (Capsicum annuum) production was evaluated from 2001 to 2003 in Iowa, comparing combinations of two synthetic fertilizers and three compost-based organic fertilizers, and a cover crop treatment of hairy vetch (Vicia villosa) and rye (Secale cereale) in a strip-tilled or fully incorporated cover crop system. Organic pepper growth and yields equaled or surpassed conventional production when nitrogen (N) was provided at 56 or 112 kg·ha−1 from compost-based organic fertilizer. Soil analysis revealed higher N in plots where cover crops were tilled compared with strip-tilled plots, leading to recommendations for sidedressing N in strip-tilled organic pepper production. Increased incidence of disease was also detected in strip-tilled plots. Postharvest weight loss after 6 weeks in storage was similar in organic and conventional peppers. The addition of calcium and sulfur products in conventional or organic fertilizer regimes did not increase pepper production or postharvest storage potential. Despite application challenges, cover crops will remain as critical components of the organic farm plan for their soil-building benefits, but supplementation with approved N sources may be required for optimal pepper production. Organic growers should conduct their own tests of organic-compliant soil amendments to determine cost effectiveness and value for their site before large-scale application.

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Benefits of Cover Crops for Soil Health

EDIS ◽

10.32473/edis-ag277-2007 ◽

2007 ◽

Vol 2007 (20) ◽

Author(s):

Yoana C. Newman ◽

David L. Wright ◽

Cheryl Mackowiak ◽

J.M.S. Scholberg ◽

C. M. Cherr

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Weed Control ◽

Cover Crops ◽

Agricultural Production ◽

Cover Crop ◽

Soil Health ◽

Nutrient Release ◽

Fact Sheet ◽

Residue Incorporation

SS-AGR-272, a 4-page fact sheet by Y.C. Newman, D.W. Wright, C. Mackowiak, J.M.S. Scholberg and C.M. Cherr, discusses the benefits of cover crops in agricultural production, the benefits of soil organic matter; how to match cover crop nutrient release with future crop demand; timing and depth of residue incorporation; and erosion, pest and weed control. Includes references. Published by the UF Department of Agronomy, November 2007. SS AGR 272/AG277: Benefits of Cover Crops for Soil Health (ufl.edu)

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