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Develop a cover cropping plan

Taking time this winter to design your cover crop plan will increase the successful establishment of the crop and potentially allow for improved staggering of fall harvest. Fall is a busy time even in a normal year. Harvesting, handling grain, fall fertility and tillage concerns are priorities. Cover crops rank about fifth. It is tough to get a cover crop established in the fall with a tight schedule for the timing.

Most farmers harvested their corn and soybeans unusually late in 2009. The opportunity to plant a fall cover crop following corn grain harvest was next to impossible. If you did not get something planted and your head hurts when you see uncovered soil all winter long, then maybe your cover crop planning needs to start earlier.

Key Points

• The best cover crop stands are planted early into a nice seedbed.

• High-clearance equipment, aerial applicators used to plant cover crops.

• Planting cover crops offers numerous advantages.

The best cover crop stands in the fall and spring are planted early, by mid-September, into a nice seedbed either tilled or no-tilled, and coinciding with rainfall. Corn silage, corn or soybean seed acres following a small grain are great options to take advantage of that perfect, early, nice seedbed planting opportunity.

If the majority of your acres are in one of these “early” production systems, you are lucky you have a larger window for planting. Most farmers, in fact, on 23 million acres in Iowa, harvest corn and soybeans for grain, which occurs late in the fall and is almost immediately followed by winter.

Cover crop plan needed

Although winter rye has been characterized as having the best “anti-freeze” of all the winter cover crops, it still needs some heat units and sunlight to grow in the fall. “Managing Cover Crops Profitably,” the encyclopedia of cover crops, reports that rye’s minimum germination temperature is 34 degrees F.

You need to answer these questions:

• Could a percentage of your land be planted to a shorter season corn hybrid or soybean variety?

• Could a percentage of your land be overseeded into standing corn or soybeans?

• Could a percentage of your land not have a cover crop?

• How can the percentages you plant be shifted to include more cover crops each year?

In 2009 several farmers worked with aerial applicators to plant cover crops by aerial seeding. The planes were loaded up with cover crop seed, and they flew the seed into standing corn or soybean acres in early to mid-September. Tillage radish, winter rye, winter wheat and mixes of cover crop species were all tested using airplanes this past fall. Some stands established well.

Other farmers used high-clearance equipment like Practical Farmers of Iowa’s Hagie Highboy or modified detasseling machines to overseed. These preharvest planting methods work well but aren’t perfect. The seed can fall onto the soil surface and germinate under the canopy given the proper moisture, but the crop canopy shades the cover crop.

Sort out your options

Weighing your options and deciding on a cover crop plan will improve your chances of a well-established, nutrient-holding, soil-improving fall cover crop.

Steve Groff from Cedar Meadow Farm in Pennsylvania talks widely about the value of cover crops especially the famous tillage radish. He says working some shorter-season varieties into the farming system will help increase cover crop establishment in the fall. Improved soil-to-seed contact and no competition for light from the standing corn or soybeans will improve the establishment of cover crops like tillage radish.

A farmer in northeast Nebraska planted 2 pounds of radish seed with German millet for a hay crop July 15 following winter wheat harvest. This tuber was harvested in November.

Planting earlier-maturing soybeans hasn’t yielded much differently. Corn is more worrisome. If you are interested in testing shorter-season corn hybrids, plus cover crop combinations, contact PFI to plan a 2010 Cooperators Project. Also, look for results from cover crop projects on the PFI Web site at

Carlson is a program specialist with Practical Farmers of Iowa in Ames. She can be contacted at 515-232-5661, ext. 305, or

Top 6 reasons for cover crops

1 They are an “in-field” practice, an investment account for the farmer, as opposed to “out-of-field” practices such as wetlands, buffers, etc., which require a subsidy from the farmer.

2 They are possible in any farming system (horticulture crops, seed beans or seed corn, silage, corn or soybeans for grain).

3 They suck up precious N before it leaches from the field.

4 They hold soil in place through winter and keep phosphorus on the farm, which would have left with the eroding soil.

5 They are precision nutrient place- ment vehicles and allow crop roots to go deeper.

6 They need to be managed. Don’t let small grains grow taller than the top of your work boot.


COVER IT: This cover crop of winter rye was planted following corn silage harvest next to a field with no cover crop in northeast Iowa.

This article published in the February, 2010 edition of WALLACES FARMER.

All rights reserved. Copyright Farm Progress Cos. 2010.