Why Barley Might Beat Cereal Rye Ahead of Corn

Cover crops ahead of soybeans get a lot of attention and cereal rye is often the first recommendation. But planting cover crops ahead of corn takes more planning and management. Illinois Soil Health Specialist Jim Isermann breaks down the key considerations for planting cover crops ahead of corn in the video to the right. Or, keep reading for the highlights.

Why Cereal Rye Can Be Challenging Ahead of Corn

Cereal rye can work before corn, but it requires careful management.

Here's why:

• Both are grasses.
• Because cereal rye and corn are in the same plant family, the risk of pests and diseases can increase.
• It can tie up nitrogen.
• If cereal rye isn't terminated early enough, it can temporarily reduce nitrogen availability for the corn crop.
• It may affect germination.
• Cereal rye can have an allelopathic effect, meaning it releases compounds that may suppress corn seed germination.

This means cereal rye ahead of corn should only be used by experienced producers with knowledge and ability to manage it.

Barley: A Simpler Option

Many farmers choose barley as a lower-risk alternative ahead of corn.

Benefits include:

• Shorter growth, typically 2 to 3 feet tall (compared to cereal rye, which can reach 6 feet).
• Slower spring growth, giving you a larger window for termination.
• Easier overall management.

Keep in mind:

• Barley isn't as winter-hardy as cereal rye.
• It needs to be planted earlier for the best chance of surviving the winter.

Timing Is Everything

For most cereal cover crops (including cereal rye, barley, wheat and triticale) a good rule of thumb is to terminate 10 days before planting corn when the cover crop is 8 to 12 inches tall. Keeping growth in that range generally makes termination easier and helps reduce potential challenges for the following corn crop.

Don't Overlook Other Cover Crop Options

Cereal cover crops aren't the only choice.

Other options include:

• Legumes
• Brassicas
• Annual ryegrass

These species can:

• Improve soil health.
• Help build nitrogen for the following corn crop.

However, they also require:

• Earlier planting dates.
• More management.
• Establishment before harvest in many cases, since planting after harvest is often too late.

Lessons from Two Very Different Years from Isermann Farm

2012: When Cover Crops Paid Off

Wet weather from hurricane remnants allowed many farmers to aerial seed cover crops before harvest. Annual ryegrass and radishes established well, and when a drought later limited forage production, those cover crops became valuable winter grazing for livestock.

The result? What started as a challenging year turned into an opportunity for Isermann Farms.

2019: When Timing Worked Against Farmers

Persistent wet weather delayed termination, leaving many fields with 5- to 6-foot cereal rye ahead of soybeans.

While most farmers avoided major disasters, many experienced yield reductions, a reminder that even good cover crop systems depend on timely management.

Bottom Line

There isn't a one-size-fits-all approach to planting cover crops ahead of corn.

Success depends on:

• Choosing the right species.
• Planting at the right time.
• Terminating on time.
• Adjusting to weather conditions.

With good planning and management, cover crops can be a valuable tool but as many Illinois farmers know, timing often makes all the difference. Watch full video of Jim Isermann explaining more.