Incorporating cover crops into corn systems

Cover crops can be successfully incorporated into various corn rotation systems. The Michigan State University Extension cover crop program has researched cultivars, timing and economics for seeding cover crops in corn.

Cultivars and timing

Cover crops can be seeded into corn at any of the three different corn growth stages. In the chart below, “A” represents overseeding when the corn is at stage V4 to V8 immediately before or after your last cultivation. The cultivars we have had the most success with are crimson clover, mammoth red clover, medium red clover, red/sweet clover mix and annual ryegrass.

Cover crop options

 

Legumes

 

Non-legumes

A

Berseem clover

A1, B1

Annual ryegrass

A, B

Crimson clover

C

Barley

A, B

Mammoth red clover

A, B

Buckwheat

A, B

Medium red clover

B

Oats

A, B

Sweet clover

B

Oilseed radish

A, B

White clover

B

Rape/turnip

A, B

60/40 mix

B, C

Rye

A1, B1

Hairy vetch

C

Triticale

A

Medic annual

C

Wheat*

A = Overseed corn at vegetative stages V4-V8
B = Overseed corn by air or highboy
C = Overseed corn by air or highboy, seeded as a cover crop
1
= Not recommended if being planted to wheat
* = After Hessian fly-free-date

“B” on the chart represents a seeding that requires special equipment, such as a highboy or an airplane. This seeding is most successful when the corn crop just begins drying down. At this time, sunlight begins breaking through the canopy, allowing cover crop growth. The cultivars that have been most successful for seeding at this time are oilseed radish, oats, rape/turnip, crimson clover, hairy vetch and red/sweet clover mix. Cereal rye can be seeded into standing corn successfully from the middle to late August.

Another window for seeding cover crops into corn occurs when the corn plants are drying down or harvested for silage (see “C” in the chart). For shelled corn, use a highboy or aerial seeding. Silage corn fields can be seeded with a bulk spreader followed by shallow tillage. The cover crops that have worked best at this corn stage are cereal rye, wheat (after Hessian fly-free date) and triticale.

Researchers’ success incorporating cover crops into corn can be directly correlated to environmental conditions. Adequate moisture and light are critical in establishing cover crops. The Michigan State University Extension cover crops team continues research on manipulating corn systems to provide a better habitat for cover crops. These projects include determining the best corn plant population, corn hybrid characteristics and development, and cover crop tolerance to herbicides.

Related resources

Related Events

Related Articles

Related Resources