Sharing the Wealth of Cover Crops: Improved cover crop and soil health knowledge sharing and networking

Final report for ES18-144

Project Type: Professional Development Program
Funds awarded in 2018: $79,091.00
Projected End Date: 09/30/2021
Grant Recipient: Virginia Tech
Region: Southern
State: Virginia
Principal Investigator:
Wade Thomason
Virginia Tech
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Project Information



Virginia is home to a strong cadre of influencers who are very enthusiastic about cover crops.  These “cover crop champions” conduct outreach throughout the state and include leading farmers as well as personnel from VA Cooperative Extension (VCE), NRCS, and other agencies and agribusinesses.  Some of our most influential cover crop champions serve dual roles as agency personnel and farmers.  We see significant opportunity for improving coordination, communication and connectivity between our cover crop champions across Virginia.  Most champions operate as individuals, conducting outreach activities and field demonstrations without much coordination with peers, especially those from other agencies or regions.  These Virginia cover crop champions are a prime example of a SARE PDP train-the-trainer audience; they are the first-tier target audience for this project.  We propose to establish an advanced train-the-trainer program and communication network that will (a) enhance the connectivity and effectiveness of our existing cover crop champions/trainers; (b) help recruit additional cover crop champions/trainers; and (c) accelerate the transfer of cover crop information and inspiration from our trainer cadre to Virginia farmers, who are the ultimate target audience for this project.  Outcomes will be continually evaluated and tactics adjusted based on feedback from participants as well as from farmer focus groups assembled specifically for that purpose.  Pre- and post-project participant surveys will be an essential component of our project; survey results will be used to assess our success in achieving the project’s ultimate goal – positive behavior change among both trainers and farmers with respect to cover crops.

Project Objectives:
  • Establishment of Virginia Cover Crop Education and Information-Sharing Network through SARE PDP
  • Creation of networked on-farm cover crop trials and educational venues for PDP trainings
  • Documentation, videoing, and curating of farmer testimonials and observations of networked cover cropping systems
  • Systematic training, sharing and networking of cover crop knowledge and practice

Integrating cover crops into agricultural systems can be one of the most important drivers of improved soil health and function.  As early as 3,000 years ago, growers were using green manure cover crops to improve soil fertility.  However, the steady increase of inorganic fertilizer use over the past 60 years and development of modern farming techniques have resulted in less diversified cropping systems.  Increasing environmental concerns associated with nutrient losses from agricultural systems, soil erosion, and high production costs coupled with low commodity prices have led many growers to reexamine cover cropping as a method of increasing soil productivity and function.  Noted effects on soil characteristics as a result of cover crops include increased organic matter (Wander et al., 1994), greater water- and nutrient-holding capacity (Weinert et al., 2002), N contribution from legumes (Vaughan and Evanylo, 1998), improved tilth and aggregate stability (Clark, 2008), and reduced erosion (Pimental et al., 1995).

Soil health management strategies, including cover crops, are known to increase hydraulic conductivity and infiltration rates (Franzluebbers, 2002; Nissen and Wander, 2003), decrease bulk density and compaction (Celik et al., 2004; Evanylo et al., 2008; Khaleel et al., 1981), enhance the size and number of water stable aggregates (Kay and Angers, 1999), lower nutrient losses (Drury et al., 2014), and improve crop yields (Munkholm et al., 2013; Schomberg et al., 2011).

Soil organic matter (SOM) content directly influences many biological, chemical, and physical properties that affect productivity.  The greatest contributor to SOM is crop/cover crop residue.  One of the many benefits of higher organic matter content in soils is improved water-holding capacity.  Soil organic matter can hold up to 20 times its weight in water (Stevenson, 1982), significantly increasing the amount of plant-available water, particularly in sandy soils.  Even in high-rainfall regions, moisture is often a limiting factor in crop production, therefore, greater plant-available water, due to higher SOM content, can increase yield by improving the overall water use efficiency (crop yield per unit of water) of the crop. 

The crumbly, friable, well-aerated soil structure associated with good tilth contributes to improved drainage, reduced crusting and ponding, and ease of seedbed preparation.  Crop rotation and use of cover crops improves soil structure by reducing the impact of compaction by increasing aggregate stability, the measure of the resistance of soil aggregates to being broken down when subjected to disruptive forces.  As early as 1967, researchers noted that aggregate stability increased from 67 to 76% when alfalfa was added to a corn-barley-sugarbeet rotation (Schumaker et al., 1967).  More recent results document that aggregate stability is consistently higher under legume (alfalfa or red clover)-corn rotations compared with continuous corn (Raimbault and Vyn, 1991).  Increased aggregate stability also reduces erosion by making the soil less vulnerable to the destructive forces of wind and rain.

Research cited by Peel (1998) found greater than 50% reduction in soil erosion when corn, barley, and hay were rotated compared with soil erosion from land in continuous corn.  The decrease in soil loss when crop rotation and cover crops are employed is due to several factors including dense canopy cover, reduced cultivation, extensive root systems, and the increased amount of residue returned to the soil. 

Improved water quality, and the role of agriculture in maintaining water quality, in the Chesapeake Bay is a long-term concern in Virginia and other Mid-Atlantic states.  In 2010, President Obama issued Executive Order 13508 that outlines strategies for reaching water quality goals in the Chesapeake Bay (Obama, 2009).  In section 202(b) of the Executive Order, agriculture is credited with reaching 50% of its targeted pollution (N, P, and sediment) reduction goal, but broader and more cohesive efforts, including accelerating conservation adoption and new technologies are needed.  Virginia has identified winter cover crops as one of five agricultural best management practices that will enable the state to reach the necessary pollution reductions.  The Commonwealth currently estimates that cover crops are planted on 100,000-120,000 acres annually (Virginia Department of Conservation and Recreation, personal communication).  However the number of acres planted to N scavenging cover crops will need to more than double to meet environmental targets.  A dramatic increase in acreage will require adaptation and innovation of the current cover crop systems so that they offer greater flexibility and greater appeal and can adapt to specific local conditions and needs.

While there are many successful cover crop “champions” and associated programs in Virginia, there is significant opportunity for improving and coordinating programming.  Too often, our current champions operate in silos without coordinating activities.  This is especially true across agencies and regions of the state.  This lack of coordination has many disadvantages, most significantly duplicative projects and the distribution of inconsistent or contradictory information to end-users by different trainers/influencers.  The sum of impacts by individuals working in isolation can be meaningful, but teamwork offers the much greater rewards of coordinated and collective impact. 


Disorder  --> Individual Impact --> Coordinated Impact --> Collective Impact

(Confusion)       (Isolation)                     (Aligned)                   (Synergistic)


The key objective of this project is to develop a core educational and information-sharing network of individuals and organizations who will: 1) Serve as a focused group and network for guiding cover crop educational programming, outreach and additional research and demonstration; and 2) Participate as the core group of cover crop “expert” trainees and mentors over the two years of this project.  We will conduct numerous in-person trainings with this group throughout Virginia showcasing diverse cropping systems.  This focused group of trainers will be the major hosts and leaders of on-farm cover crop field research and demonstration plots, a key component for information exchange with farmers.  The outcome of these efforts will be a networked group of key influencers who have cutting edge and in-depth knowledge and experience with cover crops in various cropping systems and who then serve as local/regional experts, trainers and mentors.  In addition, we will expand the VCE Cover Crop web page and Blog to be the repository for cover crop information and updates in Virginia.


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Education & Outreach Initiatives

Virginia Cover Crop College, Session101

Purposeful Cover Crop Planning


Guiding Principles

  • A cover crop for every farmer & every purpose (on flyer)
    • Cover crops fit somewhere on every farm, even if it is an unusual fit on a small % of ground
  • Relevant to every sector, size, and style of ag (on flyer)

Teaching Strategy

  • Practical & interactive (on flyer)
  • Core principles relevant to every farm & client (on flyer)
  • Case studies adapted to local area & audience (on flyer)
  • Prepping participants for problem-solving
    • “We don’t give answers, we provide tools and inspiration to help you come up with your own”
  • Networking between participants as important as teacher-to-student info transfer

Tools & resources

  • AV Tools
    • Multiple laptops and projectors (teaching projector, references projector to search internet, etc.) (Chris brings 2 projectors, 1 non-networked laptop)
    • Flipcharts or adequate white boards for small groups to make diagrams; pens
    • Overhead projector for group diagramming with larger audience (Chris provides projector)
  • Handouts (provided by Chris)
    • Packet approx. 40 pages long of key points/diagrams/tools from VA NRCS Cover Crop Planning Manual, 2nd Edition (Draft)
    • Agenda for day, Crop rotation diagraming worksheets

Excel file – Planting Date Calendars & Mix Seeding Rate Formulation Worksheets (basic version)

Outcomes and impacts:
  1. Inspire participants to analyze farming systems – their own, their clients’, etc. – and look for opportunities to insert new cover crops. Many of the obvious gaps in Virginia crop rotations are already filled with cover crops.  Therefore, taking the next step for many will require creative adjustments to crop rotations that will provide new or enhanced gaps in which to fit cover crops.
  2. Provide information, tools, and strategies to help participants better understand the full range of cover cropping options available (i.e., 30+ species, 6 seasonal niches, etc.) and come up with action plans that are both purposeful (rational, realistic) and innovative. Information and tools are designed to be applicable to wide range of clients (sector-, size-, and style-neutral).
  3. Kick off networking and partnership between participants that will extend beyond the class sessions, stimulate creativity, and help get experiments, demonstrations, and other activities on the ground.
  4. Offer resources – including funds or seed for demonstration plantings, advice, instructors, etc. – for participants to use in implementing their new ideas when they return home. Projects can include demonstration plantings, on-farm experiments, classroom education, etc. – whatever they think will benefit their local audiences and efforts.
Virginia Cover Crop College calendar and calculator

Provide users with calculations to facilitate appropriate cover crop planting dates.
Calculate seed rate for cover crop mixtures to ensure proper species composition.


Virginia Cover Crop College cover crop planting date and mixture calculator

Outcomes and impacts:

Users are better informed on planting date and cover crop seeding rates.  The tool also allows comparison of multiple scenarios for evaluation and planning.

Educational & Outreach Activities

8 On-farm demonstrations
9 Webinars / talks / presentations
7 Workshop field days

Participation Summary:

188 Extension
11 Researchers
14 Nonprofit
88 Agency
34 Ag service providers (other or unspecified)
64 Farmers/ranchers
2 Others

Learning Outcomes

325 Participants gained or increased knowledge, skills and/or attitudes about sustainable agriculture topics, practices, strategies, approaches
266 Ag professionals intend to use knowledge, attitudes, skills and/or awareness learned

Project Outcomes

2 Grants received that built upon this project
2 New working collaborations
Project outcomes:

Virginia Cooperative Extension agents, agency personnel, farmers and agribusiness now have common training on using cover crops intentionally.  They have resources for information and online calculators for seeding rates and seed mixtures.  Eight farmers have adapted their cover cropping systems to capture more biomass, improving soil health and weed suppression.  

266 Agricultural service provider participants who used knowledge and skills learned through this project (or incorporated project materials) in their educational activities, services, information products and/or tools for farmers
256 Farmers reached through participant's programs
Additional Outcomes:

Covid-19 prevented the hands-on, small group trainings that were a core part of this project.  We have used webinars and distanced field days to continue the effort, but it has limited our overall impact in 2020-21.

Information Products

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.