By Steve Groff

Maximizing cover crop benefits is a slam dunk when you plant them after wheat (or barley). Plenty of time and long days are available for them to grow to their full potential — and make them pay! Plus, dozens of species are available to include in a mix. 

But cover crops aren’t your only option. And you need to weigh them against alternatives such as soybeans or even silage corn. Then there’s the timing issue — when you can plant.

Double-crop soybeans vs. cover crops
The corridor between I-70 and I-80 is a transition zone when choosing between planting double-crop soybeans or a cover crop mix after wheat harvest. Your decision may be influenced by the date when that wheat and/or straw is removed. You also need to weigh expected soybean prices after harvest later in the fall.

Recent evidence seems to indicate more overall value to planting a cover crop compared to planting double-crop beans. Five different trials on my own farm in southeastern Pennsylvania concluded that planting a cover crop instead of double-crop beans increased corn yields the following year between 5 to 18 bushels per acre.

That yield may not make up the potential profit from double-crop beans. But the added cover crop benefits do indeed bring the use of cover crops into consideration.

Then there’s this: A small but growing number of farmers who have historically double-cropped beans after wheat now are planting cover crops instead. They’re realizing long-term benefits that cover crops can bring to regenerating their soil’s health, by making it more resilient to future stress, such as drought and poorly drained conditions.

Plant cover crops how soon?
I usually recommend planting cover crops as soon as possible after the combine leaves or the straw is baled. There are a couple big “howevers.”

If significant weeds are present, it’s advisable to wait a few days. Terminate the weeds, then plant the cover crop.

Volunteer wheat may also compete with your cover crop, especially if the straw was windrowed for baling and wheat kernels that passed through the combine are concentrated in a narrow strip. If a shower of rain happens to occur, those wheat seeds may germinate and be easy to control in two weeks or so.

Or, if it’s dry and no rain is in sight, it may be best to go ahead and plant your cover crop. That’s particularly true if there’s still enough moisture at planting depth for your cover crop to begin growing.

Which covers to plant?
Some of the most popular cover crops are sorghum sudangrass, sunn hemp, radishes, cowpeas, buckwheat, millet and oats. There are many more. But it comes down to what you’re trying to accomplish in the next season.

If corn is planned to be your next crop, you’ll want to lean more to legume cover crops. For soybeans, a majority of grass species is desired. If you have cattle, you may want to plant an appropriate grazing mix.

This is also an opportunity to grow a cover crop for September forage harvest. If there’s enough time in the growing season, a subsequent winter cover crop could be planted to cover the fields for the winter.

For this coming season, I plan to test a strategy of sowing sorghum sudangrass, sunn hemp, triticale, hairy vetch and radish immediately after wheat harvest. The warm-season cover crops in this mix will clearly dominate and be harvested as wet baleage in early September. Then, cool-season cover crops will be positioned to grow over winter. That assumes they’ll survive under the sorghum sudangrass/sunn hemp canopy during late summer.

The coach’s closer
I can assure remaining skeptics that cover crops will pay when planted after wheat. A strategically crafted cover crop mix may indeed provide a competitive value, or even greater value, than double-crop beans, especially the farther north you are. Why not try it in a field or two this year!

Groff, who farms on the Chesapeake Bay watershed, is a cover crop pioneer and innovator. Check out his website, CoverCropCoaching.