Corn after a Cereal Rye Cover Crop in 2021

Original Post: Mark Licht , April 2021; Integrated Crop Management News, and Iowa State University Extension and Outreach

With cool weather conditions potentially causing delays in cover crop termination, what options are available? 

Cereal rye ahead of soybean is not nearly as problematic. While planting green may not be advised for beginning cover crop users, more experienced cover crop users have planted soybean into green cereal rye.

There are two main considerations. First, make sure the planter is setup properly for the seedbed conditions. This means making sure row unit down pressure is adequate to ensure proper seed placement depth, and the closing wheels are fully closing the seed furrow. Second, is to terminate the cereal rye soon after soybean planting. I am recommending cereal rye be terminated soon after soybean planting this year because, at present, dry conditions are prevailing across much of the state.

For cereal rye ahead of corn, terminating more than 10 to 14 days ahead of corn planting is preferable. There are reports ‘yellow’ cereal rye can cause wrapping in the residue cleaners. Whatever the termination timing, there will likely be increased implications associated with seedling disease, allelopathy, and nitrogen cycling.

Two recent blogs (blog 1blog 2) from Alison Robertson’s lab tell that temporal and spatial distancing of cereal rye and corn reduced the severity of Pythium seedling infection and mitigated yield loss. Lab studies have also demonstrated that allelochemicals may interact with Pythium to cause more severe seedling disease (Acharya et al. 2021). However, we have a poor understanding of the allelopathic affect in the field. It almost certainly can reduce corn seedling vigor and can be minimized by with more time between cereal rye termination and corn planting. There are also several potential impacts involving nitrogen availability for the corn seedling. We know that cereal rye will take up soil nitrate, and recycle soil nitrogen at some time throughout the growing season. The decomposition of cereal rye immobilizes soil nitrogen in the short-term, and more nitrogen is immobilized if the cereal rye had begun jointing at or before termination.

This year it is likely that corn will be planted green or the termination to planting timeframe will be narrow. Based on our experience, the amount of cereal rye biomass may make a difference. More biomass relates to more severe disease, allelopathy, and nitrogen implications. If the cereal rye is less than 8 inches the risk of nitrogen immobilization and disease infection should be minimal. If the cereal rye is greater than 12 inches consider increasing the corn seeding rate 5 to 10 percent to counteract potential stand loss due to Pythium seedling mortality. All corn seed is treated with fungicides; check your seed label to see what fungicides are on your seed. Mefenoxam, metalaxyl and ethaboxam are fungicides that have excellent efficacy against Pythium. Pyraclostrobin, azoxystrobin and trifloxystrobin also have some activity. Using Priaxor in-furrow could help minimize seedling disease. While Priaxor is labeled for in-furrow applications, there is no public research that we know of that has tested Priaxor under this type of situation. And finally, consider using starter nitrogen and/or applying the remainder of your nitrogen program at an early vegetative stage to ensure sufficient nitrogen supply. Keep in mind that John Sawyer and others have found that corn following cereal rye does not justify a higher nitrogen rate.

Spring Cover Crop Termination Tips & More!

Last spring the Whole Farm Conservation Best Practices Manual was released and offers some great tips for spring management of cover crops – from termination to planter settings and more!

Cover crops that survive the winter, like cereal rye, must be terminated in the spring ahead of planting, to avoid affecting corn and soybean crop yields. There are four methods of termination approved by RMA to fully insure the upcoming corn and soybeans. Their success rate and the confidence in that success is illustrated in the graphic below.

Timing is also an important factor in successful termination.

  • With corn, terminate the cover crop before it is 8 inches tall, and 10 to 14 days before planting corn.
  • With soybean, terminate the cover crop before it is 12 inches tall, and 3 to 7 days before planting soybean.
  • If spring weather conditions are abnormally dry, terminate cover crops earlier than otherwise recommended.

Planting corn or soybean after a cover crop requires minimal change. Follow best management practices for the corn or soybean crop, and the fundamental principles that maximize production efficiency:

  • Plant based on soil conditions, but realize that suitable soil conditions may be a day or two later than without cover crops.
  • Wait for conducive field conditions with a soil temperature at 50ºF and rising. At a soil temperature of 50ºF or warmer, there is robust seed germination, and vigorous seedling emergence, growth, and establishment.

Nitrogen management is also important to consider when corn is following cereal rye.

  • Move nitrogen application to the spring close to the time of corn planting.
  • Starter fertilizers may be beneficial to minimize impact of nitrogen immobilization due to cover crop root and residue decomposition.
  • There is no need to adjust nitrogen rates following winter cereal grain cover crops.

Four more tips for managing cover crops successfully.

Be sure to subscribe to our blog to keep up to date on the latest Cover Crop Corner posts and more great content.

Liz Ripley

Economic Considerations on Cover Crop Adoption

Alejandro Plastina, associate professor and extension economist at Iowa State University, addressed the profitability of winter cover crops in Iowa from the producer’s perspective, based on agronomic experiments and surveys of farmers, during the Iowa Learning Farms webinar on Wednesday.

There are several reasons to use cover crops, including improved soil health and reduced soil erosion, water quality benefits, and pest management. Despite these benefits, the adoption rate of cover crops in Iowa is low, only growing from 1% in 2012 to 4% in 2017. Plastina hypothesized why the adoption rate is so low and shared four analyses that he used to support his claims about why the cover crop adoption rate in Iowa is low.

Research started with several focus groups, during which experienced cover crop users were asked about their motivations for cover crop use, and partial budgets were used to put numbers behind the perceived returns and costs of cover crops. To get a larger sample size, they then conducted a regional online survey across several midwestern states. A state-wide mailed survey was also sent to producers in Iowa who indicated they planted at least 10 acres of cover crops in the 2012 Census of Agriculture. In response to criticism of the state-wide survey results, Plastina conducted surveys in other states and a study in Iowa that assessed net returns based on experimental data.

Plastina encouraged webinar attendees to use two tools to create their own partial budgets and see the expected economic benefits and costs of cover crops in their operations:

To learn more about the economics of cover crops, watch the full webinar!

Join us on Wednesday, March 31 at noon, for the webinar, “When, Where and Why Soil Erosion Occurs and When, Where and How Do We Control It” with Rick Cruse, professor at Iowa State University and director of the Iowa Water Center.

Hilary Pierce

March 24 Webinar: Economic Considerations on Cover Crop Adoption

Learn about the economics of cover crops during the Iowa Learning Farms webinar on Wednesday, March 24 at noon.

Alejandro Plastina, associate professor and extension economist at Iowa State University, will address the profitability of winter cover crops in Iowa from the producer’s perspective, based on agronomic experiments and surveys of farmers. Plastina will also present two decision tools that can be used to calculate farmers’ own expected net returns on cover crops.

The presentation will conclude with a discussion of the relative costs of nitrate leaching abatement through cover crops borne by farmers and taxpayers, and a brief discussion on why it is too early to think about monetizing soil health improvements.

“Cover crops are a good farming practice, but they are only profitable for a small percentage of farms,” said Plastina. “Webinar participants will learn how they are able to use a decision tool to calculate their expected net returns on cover crops.”

Dr. Plastina’s research and extension program focuses on farm business and financial management, with a particular emphasis on the economics of conservation practices.

Webinar Access Instructions

To participate in the live webinar, shortly before 12 pm CDT on March 24:

Click this URL, or type this web address into your internet browser:

    Or, go to and enter meeting ID: 364 284 172 

Or, join from a dial-in phone line:

    Dial: +1 312 626 6799 or +1 646 876 9923

    Meeting ID: 364 284 172

The webinar will also be recorded and archived on the ILF website, so that it can be watched at any time. Archived webinars are available at

A Certified Crop Adviser board-approved continuing education unit (CEU) has been applied for, for those who are able to participate in the live webinar. Information about how to apply to receive the credit will be provided at the end of the live webinar.

Hilary Pierce

Conservation Learning Lab: Implementation of Cover Crops at Small Watershed Scale

Matt Helmers, director, Iowa Nutrient Research Center, shared the results of three years of water quality monitoring data after cover crop implementation during the Iowa Learning Farms webinar on Wednesday. The Conservation Learning Lab (CLL) project, started in 2016, posed the question, “Can high levels of cover crop implementation and reduced tillage be obtained on a small watershed scale, and water quality improvement documented accordingly?” The project focused on small watersheds—between 500 and 1,300 total acres in size.

Two pilot watersheds were chosen in Floyd County and Story County. These watersheds were chosen based on their size and that they had existing Conservation Reserve Enhancement Program (CREP) wetlands that provided baseline water quality monitoring data. This allowed for the comparison of water quality before and after conservation practice implementation and to a similarly sized control watershed that did not implement conservation practices. The figures above show the adoption of cover crops and strip-tillage in the two pilot watersheds for the CLL project.

The results of the study indicated that, to date, there has not been a noticeable reduction in nutrient loss at the small watershed scale due to the implementation of cover crops within the watershed. This may be because the entire watershed area was not treated with cover crops and a higher rate of adoption may yield noticeable water quality benefits. There may also be some lag time between implementation and noticeable results, which emphasizes the importance of continuing to monitor the results over several years. Growth of the cover crops is another factor that may impact the water quality benefits, as shown in other research, and may be the critical factor in this study. Some fields in the study were seeded with rye, while others were seeded with oats and it expected that oats will have less of an impact on water quality.

To learn more about this project, watch the full webinar!

Join us next week, on Wednesday, March 10 at noon, for the webinar, “Cropping System Diversification is a Path to Greater Sustainability,” presented by Dr. Matt Liebman, professor of agronomy and H. A. Wallace Chair for Sustainable Agriculture at Iowa State University (ISU).

Hilary Pierce

A Cover Crop Conference For Everyone

The countdown is on to the Midwest Cover Crops Council Conference!

Organized by OMAFRA, the Ridgetown Business Development Centre, and SOILS AT GUELPH, this virtual conference running February 23-25 will have something for everyone! This year’s theme is Making Connections: Soil Health, Cover Crops, and People.

For only $35, attendees get access to 10 incredible live discussions, plus the ability re-watch the sessions for one month following the conference.

The annual business meeting will be held on February 23 and will include updates from Ontario and each of twelve Midwestern states. Several MCCC partners will also share updates. This is a great opportunity to learn about cover crop research and programs across the Midwest.

Kickstarting the conference on the evening of February 23, Jenn Doelman, Odette Ménard, Greg Hannam, and Philip Shaw will discuss “Finding Common Ground on Cover Crops”. Moderated by Lauren Van Ewyck, this panel will home in on where cover crops can meet everyone’s shared goals.

February 24 is packed with amazing content! We have three of the world’s leading soil biologists ready to share how science’s latest achievements can improve our management of the living soil. And don’t miss our Keynote Conversation featuring Roger L. Martin – the world’s #1 management thinker! Roger joins Mel Luymes to lay out the principles for achieving a balance of efficiency with resilience in agriculture; and Crystal Mackay (Loft32), Dan Petker (CCA-ON), Dr. Alfons Weersink (University of Guelph), and Cher Mereweather (Provision Coalition) will further unpack what these principles mean for the agri-food industry.

February 25 rounds out the conference offering system-specific sessions for grain and oilseed producers, vegetable growers, and livestock farmers. Catch Dr. David Hooker, Rodney Rulon, Dr. Julie Grossman, Ried Allaway, Marie Shea, Dr. Melissa Wilson, and more during Thursday’s sessions.

And when you’ve poured your afternoon hot beverage, join us on our Cover Crop Coffee Breaks at 3pm, February 24 and 25, to chat with more cover crop experts!

Finally, we want to properly recognize a few key conference sponsors: the Ontario Agricultural College, Syngenta, the Grain Farmers of Ontario, the Mosaic Company, and Cribit Seeds. Bringing together this stellar speaker lineup on a high-quality virtual platform would not be possible without their support.

Visit to register and view the full conference lineup, or contact us for information. We can’t wait to see you there!

Cameron Ogilvie, SOILS AT GUELPH
Conference Coordinator

Loree Elgie, Ridgetown BDC
Conference Sponsorship Lead

Crop Insurance Discounts for Cover Crop Use in High Demand

Modeled after the Cover Crop Crop Insurance Project led by the Iowa Department of Agriculture and Land Stewardship, the Illinois Fall Covers for Spring Savings Program has encouraged more farmers to plant cover crops in the 2020-2021 crop year.

This year, the Illinois program filled up in less than 24 hours and Kris Reynolds, Midwest Director of the American Farmland Trust, hopes that the Illinois Department of Agriculture will consider including more money for cover crop programs in the future. Through success first shown in Iowa and now Illinois, other states considering adopting a similar program include Indiana, Wisconsin and Minnesota.

Be sure to check out the full story published by Harvest Public Media on January 29, 2021, here.

Liz Ripley

Perennial Groundcovers for Achieving Soil & Water Conservation with Large-Scale, High-Yield, Row Crop Production

During the Iowa Learning Farms webinar on Wednesday, Cynthia Bartel, research scientist at the Iowa State University Biomass Cropping Systems Lab, discussed research studies that explore how to integrate perennial groundcover into row crop systems.

Perennial groundcovers (PGC) are crops that cover the soil, such as living mulches, perennial cover crops, and self-reseeding annuals, and are sometimes also referred to as intercrops. Using PGC has natural resources benefits, including reduced soil erosion, reduced nitrate leaching, enhanced organic matter, weed control, and carbon sequestration. The use of groundcover makes the coverall system more resilient in a cost-effective manner.

Bartel shared information about a three year study that looked at corn yield where fescue or bluegrass was used as PGC. During the first year, there was lost yield under the PGC systems, but as the system was adapted and best management practices were developed, the PGC systems matched the yield of the control acres. There are also on-farm trials being done in Iowa with corn and soybean, which have recently been expanded into states to the south after positive results in Iowa. As the result of these studies, desirable traits of PGC and best practices for systems management have been identified.

To learn more about PGC systems, management, current field research, stakeholders, and economics, watch the full webinar here!

The Iowa Learning Farms webinar series will continue in 2021! Join us on Wednesday, January 6 at noon for our next webinar, “Turning Red Acres Green,” with Josh Divan, precision ag and conservation specialist at Iowa Pheasants Forever.

Hilary Pierce

Virtual Field Day November 24: Making Cover Crops and Strip-Tillage Work in the Des Moines Lobe

Iowa Learning Farms, in partnership with the Iowa Nutrient Research Center, and Conservation Learning Group (CLG), is hosting a free virtual field day with Mark Thompson, Webster County farmer who is making cover crops and strip-tillage work in the Des Moines Lobe on Tuesday, November 24th at 1 p.m. CST.

Located in the heart of the Des Moines Lobe, known for the rich, dark soil, Thompson has been utilizing no-till on all soybean acres and strip-till on his corn acres since 2002. During the virtual field day, Thompson will share his experiences figuring out which strip-till tools and timing of operations work best for his system.

“At first, it was an economics thing, then I found out that conservation, nutrient management and erosion control came along with it,” said Thompson. “If you have never tried no-till, try some no-till beans. You will be shocked how well it works and how easy it is – just hesitate to do any tillage in the fall and plant right into the corn stalks.”

Thompson first started using cover crops as a prevented planting measure in 2013. Observing the benefits to the land and reduction in soil erosion, he has continued to increase his use of cover crops acres and now raises cereal rye to provide cover crop seed to the rest of his farm. Thompson also takes a conservation approach as a professional farm manager and encourages the increased adoption of practices like cover crops and strip-till across the state.

To participate in the live virtual field day at 1:00 pm CDT on November 24th, click HERE: or visit and click “Join Live Virtual Field Day”. 

Or, join from a dial-in phone line:

    Dial: +1 312 626 6799 or +1 646 876 9923

    Meeting ID: 914 1198 4892

The field day will be recorded and archived on the ILF website so that it can be watched at any time. The archive will be available at

Participants may be eligible for a Certified Crop Adviser board-approved continuing education unit (CEU). Information about how to apply to receive the credit (if approved) will be provided at the end of the live field day.

Liz Ripley

Midwest Cover Crop Council Launches Updated Cover Crop Selector Tools

The Midwest Cover Crop Council (MCCC) Cover Crop Decision Tools are web-based systems to assist farmers in selecting cover crops to include in field crop and vegetable rotations.

The Cover Crop Decision Tools are an initiative by the MCCC to consolidate cover crop information by state to help farmers make cover crop selections at the county level. Information for each state/province is developed by a team of cover crop experts including university researchers, Extension educators, NRCS personnel, agriculture department personnel, crop advisors, seed suppliers and farmers. The team reviewed and refined information from the Sustainable Agriculture Research and Education (SARE)  publication Managing Cover Crops Profitably, 3rd edition to refine application within their state/province. The information and ratings contained in the Cover Crop Decision Tool is the team consensus based on literature, research results, on-farm experience and practical knowledge.

Decision Tool Q&A Webinar

Wednesday, September 23rd at Noon Eastern / 11:00 am Central

Join MCCC for an in-depth look at the revised decision tool with Babak Saravi, Ian Kropp with the Decision Support and Informatics Lab of Michigan State University and Dean Baas and Anna Morrow with the Midwest Cover Crops Council.

This webinar will be recorded and posted here for later viewing.

Register Here

Liz Ripley