Looking for tips for managing your cover crops this spring?
Check out this throwback Thursday video from 2011 featuring Sarah Carlson with Practical Farmers of Iowa with recommendations for terminating an overwintering cover crop like cereal rye.
For more cover crop and other conservation practice-related videos, visit our YouTube channel and subscribe to stay updated on virtual field days.
For many livestock producers, cover crops and winter grazing go hand-in-hand; however, perhaps the most valuable time for grazing cover crops is in the spring. Winter annual cereal grains such as rye, wheat, and triticale grow fastest and provide the most tonnage in the early spring, before cool-season grasses start to grow. With proper management, soil compaction from grazing cover crops can be minimized as demonstrated in two case studies evaluating impacts of grazing corn stalk residue with and without cover crops.
Check out these infographics for tips for spring grazing cover crops and avoiding compaction:
The Whole Farm Conservation Best Practices Manual offers 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.
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:
Nitrogen management is also important to consider when corn is following cereal rye.
Four more tips for managing cover crops successfully.
Wishing everyone a safe and successful planting season!
Have you enrolled in the Crop Insurance Discount Program jointly administered by the Iowa Department of Agriculture and Land Stewardship and United States Department of Agriculture (USDA) Risk Management Agency (RMA)?
If not, there is still time to sign up today before the applications close tomorrow, Friday, January 26th.
The program provides farmers and landowners who plant fall cover crops the opportunity to apply for a $5 per acre discount on their spring crop insurance premiums. To sign up to participate, visit Apply.CleanWaterIowa.org.
To qualify for the Crop Insurance Discount Program, the cover crop acres cannot be enrolled in other state or federal cost share programs. Farmers should visit their local USDA Service Center to learn about other cost share funding available to support the implementation of conservation practices. Some insurance policies, such as Whole-Farm Revenue Protection or those covered through written agreements, may be excluded. Participants must follow all existing farming practices required by their respective policy and work with their insurance agencies to maintain eligibility.
Registration is now open for the 2024 Midwest Cover Crop Council Annual Meeting and Conference. Held in Indianapolis, Indiana, on February 13-14, the annual meeting is an opportunity for farmers, landowners, researchers, and agency partners to gather to share ideas and learn about recent cover crop research.
Register today and receive an early registration discount through December 15th. Student registration is free, and students are invited to submit an entry for the poster competition.
Learn more about the Midwest Cover Crop Council and the cover crop selector tools by visiting https://www.midwestcovercrops.org/
Sharing this 2020 Practical Farmers of Iowa post sharing results from Iowa Learning Farms farmer partner Wade Dooley‘s trial with seeding cereal rye each month of the year as part of an informal trial.
Starting in the fall of 2018, and into the spring of 2019, Wade began drilling rye into an 80-acre field in quarter-mile-long strips at 1 bushel an acre. He tried to complete as many passes as possible with rye in the drill before it got too muddy for the equipment. Wade made these passes every few weeks after the frost softened in the mornings.
By November 2019, Wade had drilled rye every month of the year – in the process, had pushed the envelope on seeding.
Observation 1: Rye can be planted all the way till spring of a following year, but don’t expect a good stand come corn and soybean planting time.
In mid-May, when Wade went to plant soybeans, he found – as he expected – that stands of cereal rye seeded at different dates resulted in differing spring performance. The rye drilled during the early fall of 2018 had the best stand, unsurprisingly, as indicated by the number of shoots (known as tillers) on the plants. The cover crop seeded closer to March had germinated but not tillered, which created a thin stand when the soybeans were planted.
Observation 2: Seeding cover crops past March 20, 2019 conditions did not allow for vernalization.
Wade wondered if the March planted rye would stay vegetative or produce flowers. Because rye needs exposure to prolonged cold weather to trigger flowering, a process called vernalization, most often any rye seeded after March 20 will fail to flower and will remain supple and grass-like. All rye planted before March 20, 2019 initiated flowering. The rye seeded March 20 rye did not.
Observation 3: If your goal is weed control plant in October or November. Don’t wait!
As for weed control, Wade found that the mid-fall seeding worked best – another result he anticipated. If you have high weed pressure plan to seed cover crops before ground freezes. If your fields have mid to low weed pressure, you can seed into February, but Wade does not recommend seeding into March.
Wade observed that the non-vernalized rye performed the worst at weed control. Wade also reported that all of the stands were easy to terminate with Roundup, which he did after no-till planting soybeans directly into the cover crop.
Observation 4: Keep your end goal in mind, and be willing to adjust practices
No matter when you seed cover crops, it is important to determine your goals for seeding cover crops. Your goals will guide what would be best practices, even if you seed cover crops late. If you are aiming for the best weed control in the spring, your seeding rates will need to be increased substantially if you seed the rye in the dormant timeframe. Wade recommends at least doubling the amount you normally seed if not triple the amount in order to obtain the best weed control.
If your goal is to improve the soil quality, then simply getting the seed in the ground is the most important factor to consider. With this in mind, drilling is going to work better than broadcasting with incorporation – which is going to work better than just broadcasting. But Wade quips: “Broadcasting the seed is still better than just leaving the seed in the shed.”
Last fall, Wade provided some rough guidelines on how you might adjust seeding rate based on seeding timing and your goals:
| Goal | Before Nov. 3 seeding rate | After Nov. 3 seeding rate |
| Erosion control, soil health, water quality improvement | 1 bu/ac drilled | 1.5 bu/ac |
| Weed control, harvesting ryelage, spring grazing | 2 bu/ac drilled | 3 bu/ac* |
| *Wade has observed a rye cover crop typically won’t provide enough biomass for ryelage or grazing in the spring if planted after mid-November. | ||
As you consider the possibility of seeding cover crops late in the year, it is also important to keep cost in mind. While Wade’s research has shown it’s possible to seed rye later in the year, you may not get the economic value that you would have gotten if you had seeded earlier.
Because weather is so variable from one year to the next, Wade doesn’t try to seed his cover crops by a hard-and-fast date. However, he does generally aim to finish seeding cereal rye by Thanksgiving, but in ideal conditions the earlier the better for him personally.
Registration is now open for the 34th Integrated Crop Management Conference. The ICM Conference brings together a diverse range of topics, slate of expert presenters and results of the latest University research. Drawing crop production professionals from across Iowa and the Midwest together for two days to learn, listen and share this is an event you won’t want to miss.
A 2023 guest speaker is Iowa Learning Farms farmer partner Kellie Blair, as a member of the panel discussing the impacts of the Endangered Species Act for Midwestern agriculture. Additionally, there are multiple speakers discussing cover crops on both days of the conference.
Check out the whole program for additional details on speakers and topics and note the change of venue this year to The Meadows Events Center at Prairie Meadows Racetrack, Casino and Hotel in Altoona, Iowa. The new location offers on-site hotel accommodations, ample free parking, and a wide range of nearby dining and entertainment options. Pre-registration is required to attend the conference. Registrations must be received prior to midnight, November 27, 2023.
Practical Farmers of Iowa recently released the results from the 2023 Cereal Rye and Triticale Variety Trial conducted at four Iowa State University Research Farms.
Funded by USDA-NIFA, Walton Family Foundation, Albert Lea Seed House, Green Cover, North Dakota State University and KWS, the project is in it’s fifth year and will expand with the establishment of the recent National Conservation Innovation Grant project involving relay intercropping.
Key Findings:
Be sure to check out the full report on the rye and triticale variety trial and look for the oat variety trial results to be available soon.
For many parts of Iowa, 2023 is the third consecutive year of drought conditions. This has made establishing cover crops challenging. Drought conditions make overseeding cover crops into standing corn and soybean less successful because of a lack of rainfall to get seeds to germinate. Advice to this point in the growing season has been to postpone overseeding of cover crops (or if you were lucky, overseed ahead of the past weekend’s rain).
Instead of overseeding, the best chance of getting adequate cover crop establishment this fall is to drill seed following soybean or corn harvest. This will provide the best seed to soil contact and therefore best chance of the seed absorbing moisture to initiate germination. In the driest areas that missed last weekend’s rain, it will still take some rain. However, drill seeding will protect more of the seed from scavenging birds and rodents.
A second best practice for planting cover crops in a drought year is to switch to winter small grains like cereal rye, winter wheat, or winter triticale. These species are fast to germinate and can tolerate cooler temperatures than brassica and legume species. Additionally, in the spring, they will get off to an early start and have the potential to produce large amounts of biomass.
Oats would be another alternative if you are able to drill seed before October 1. In most cases, this will be fields that have been harvested for silage corn, high moisture corn, or early maturing soybean. The oats will winter kill. To get the most out of oats, consider seeding at greater than 60 pounds/acre.
Regardless of the timing of cover crop seeding, consider doing a bioassay to determine if there are residual herbicides that would impact the germination and growth of a cover crop this fall.
Spring considerations:
Cover crops are a great non-herbicide tool for suppression of problematic weeds. One attribute of cover crops that help control weeds is having the ability to produce large amount of biomass. If weed suppression is your cover crop goal, make sure to seed at a higher seeding rate (greater than 70 pounds/acre for most small grains).
Keep an eye on the U.S. Drought Monitor and how much rainfall and snowfall you have received. Factor in how much water is infiltrating (aka soil moisture recharge) versus running off from high intensity storms or as snow melt on frozen soils. If soil moisture reserves have not been filled and precipitation patterns indicate a dry spring, consider terminating overwintering cover crops early to avoid early and shallow soil moisture deficits for the 2024 corn and soybean crop.
Additional resources:
Whole Farm Conservation Best Practices Manual
The Time for Seeding Cover Crops is Upon Us
Tips and Considerations For Getting Started With Cover Crops
–Liz Ripley and Mark Licht
While the registration of 2,4-D and dicamba products for over-the-top use in resistant-varieties has improved waterhemp control for many farmers, weed scientists warned that these herbicides would eventually select for resistant waterhemp populations. Bayer recently reported the discovery of two likely dicamba-resistant waterhemp populations in Iowa, which warrants a discussion on best management practices to slow the evolution of resistant waterhemp populations.
On Friday, September 1, Bayer released an external communication reporting that suspected dicamba-resistant waterhemp populations were sampled in Scott County in 2021 and Marshall County in 2022. After extensive screening the company states they are likely resistant to dicamba but will continue testing to positively confirm the resistance. This is the first case of plant growth regulator (HG 4) resistant waterhemp in Iowa, though other states have already documented HG 4 resistance in their own waterhemp populations. HG 4-resistant waterhemp were documented by university researchers in Nebraska in 2009, Illinois in 2016, and Missouri in 2018.
This discovery is not a cause for panic, but it is an important reality check for farmers who rely heavily on HG 4 herbicides or any other individual herbicide group for waterhemp control. Waterhemp is known for its ability to quickly adapt to herbicide management tactics; Iowa State University has already officially documented resistance to five HGs in Iowa waterhemp populations (Table 1).
| Herbicide Group (HG) Number | Herbicide Trade Name Example | Resistance First Officially Documented |
|---|---|---|
| 2 | Pursuit, FirstRate | 1993 |
| 5 | Atrazine, metribuzin | 1996 |
| 9 | Roundup | 2009 |
| 14 | Flexstar, Valor | 2009 |
| 27 | Armezon, Callisto | 2011 |
While herbicides remain a primary tactic to manage many weed species, farmers can implement several best management practices to slow resistance development and better control weeds like waterhemp.
While many waterhemp have seed at this point in the growing season, farmers still can reduce the spread of any waterhemp seed yet this fall. Specifically, consider these management recommendations:
Please report incidences of non-performance of products to their respective manufacturers. While Iowa State University doesn’t currently have capability to test resistant populations, please report suspected HG 4-resistant waterhemp populations to Meaghan Anderson, Iowa State University Extension and Outreach field agronomist.
Original post by Meaghan Anderson, Iowa State University Extension and Outreach Field Agronomist, on September 5 via Integrated Crop Management News.
Iowa Learning Farms 