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Serving: IA
Timely tips for managing cover crops this spring

Timely tips for managing cover crops this spring

Iowa specialists share spring management tips for farmers new to growing cover crops.

As the number of Iowa farmers using cover crops continues to grow, it's important to help make sure these farmers have a successful experience. The Iowa Cover Crop Working Group has released timely information and is sharing these spring management tips with farmers to ensure continued success.

The Iowa Cover Crop Working Group is made up of specialists and representatives of agencies and organizations and who are knowledgeable about them. This includes Iowa State University specialists, farm organization representatives and representatives of agencies involved with cover crops and soil and water conservation.

Related: University study: Use cover crops to lure deer from livestock feed

HELPFUL INFO: Iowa's "Cover Crop Working Group" is made up of various sources of information on cover crop management. They are making a special effort this spring to help farmers new to using cover crops have a successful experience.

"We have seen tremendous growth in the number of farmers using cover crops on their farms, as they seek to reduce soil erosion, protect water quality and improve soil health," observes Iowa Secretary of Agriculture Bill Northey.  "As with any new practice there can be a significant learning curve. These tips can hopefully help farmers have a successful experience which encourages them to grow cover crops again in the future."

Sharing information on managing cover crops this spring
The following information was put together with the help of the Iowa Cover Crop Working Group, which includes representatives from the Iowa Department of Agriculture & Land Stewardship, Practical Farmers of Iowa, Iowa State University, Iowa Learning Farms, and USDA Agriculture Research Service.  More information about incorporating them into your farming operation can be found at  or at

Evaluate for winterkill – If the above ground portion of the cover crop is brown and near the soil surface there is no green plant material present, then it has winterkilled. Cover crops such as tillage radishes and oats typically winterkill and in that case no additional spring management is needed. Other cover crops, such as winter rye or cereal rye, winter wheat, triticale, and barley, consistently over-winter in Iowa. In late March and in early April,

Thinking About A Cover Crop? Start With Developing A Plan
Taking time to design your cover crop plan will increase the successful establishment of the crop and potentially allow for improved staggering of fall harvest.

Termination options – What's the best way to kill a cover crop in the spring? Herbicides, tillage or a combination of the two can be used to effectively manage cover crops in the spring. Keep in mind any tillage will reduce the effectiveness of the residue to protect against erosion and suppress weeds. Here are some additional considerations for both methods of termination:


Herbicide: For successful termination of a cover crop by spraying it with an herbicide, make sure the plant has "greened-up" and has enough living surface area for the herbicide to work. Experienced farmers suggest spraying during the middle of the day and, if possible, spray when air temperature is at least 45 or 50 degrees F. Unless you have experience using both at the same time, you should separate the nitrogen application from a "burndown" herbicide application.

Related: Extensive body of cover crop science available online

Tillage: Terminating cover crops with tillage can be effective, but may take more than one tillage pass. Wet weather periods can delay tillage to terminate cover crops and wet conditions following tillage can allow cover crop plants to survive tillage operations.  Also, tilling a cover crop to terminate it eliminates the erosion prevention benefit that the cover crop would usually provide in the early part of the growing season.

Consider nitrogen needs – Cover crops effectively sequester nitrogen and as the plant residue breaks down it will release its nutrients, making them available for the cash crop (such as corn or soybeans) later in the season when that crop needs the nutrients the most. However, there is the potential for lower amounts of available nitrogen to be present early in the growing season, especially following an overwintering grass cover crop like cereal rye. To protect their corn yield, farmers growing corn after a cereal rye cover crop may want to apply 30 to 50 lbs. of nitrogen per acre at or near corn planting. This is not additional nitrogen, but within the farmer's total fertilizer program.

Know your crop insurance requirements – Crop insurance rules state that a cover crop in Zone 3 (western third of Iowa) must be terminated by the day of cash crop planting. A cover crop in Zone 4 (eastern two-thirds of Iowa) must be terminated within 5 days of cash crop planting. If using no-till add 7 days to either scenario. More information about crop insurance requirements can be found at

Start planning now for cover crop needs this fall – Determine what cover crop or mixture of cover crop species work with your current or planned crop protection program. Some residual herbicides have carryover restrictions for certain species. Consult with your agronomist and/or cover crop seed representative to look at your specific management system with the integration of cover crops. Additional information can be found at

Thinking About A Cover Crop? Start With Developing A Plan
Taking time to design your cover crop plan will increase the successful establishment of the crop and potentially allow for improved staggering of fall harvest.

More than 1,600 farmers statewide in Iowa have volunteered to invest $4.2 million to try a new practice on their farm to better protect water quality over the past two years through the Iowa Water Quality Initiative. Thousands of other Iowa farmers are using cost-share funding through other state and federal programs, or are growing cover crops on their own with no government financial assistance.

The state also currently has 16 Iowa Water Quality Initiative demonstration projects on-going in targeted watersheds that are focused on helping farmers implement and demonstrate water quality practices. The state has provided $7.4 million in funding to support these projects and has leveraged an additional $11.7 million in additional funding from partners and landowners. More than 95 organizations are participating in these projects.

Related: Extensive body of cover crop science available online

Visit to learn more about voluntary, science-based practices that can be used on farms and in cities to improve water quality. Iowans can also follow @CleanWaterIowa on twitter or "like" the page on Facebook to receive updates and other information about the ongoing Iowa water quality initiative. The Midwest Cover Crops Council also has information available about cover crop studies. For this free information visit

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