Tools Suited to the Task

December 13, 2013 06:14 PM
Tools Suited to the Task

Cover crop interseeders help hurdle the time crunch

Cover crops are gaining ground in the U.S., but their adoption has not been without a number of bumps. Planting the crops on a timely basis is a top challenge farmers have wrangled with along the way.

New machinery options are looking to solve the time crunch in getting cover crops off to a strong start.

"Often, grain harvests are so late, there’s little to no opportunity to no-till drill cover crops here," explains Ron Hoover, Pennsylvania State University (PSU) coordinator of on-farm research. "Farmers could go to shorter season corn, but there is concern they’ll give up some yield if they do, so interseeding is a good option."

To maximize corn yields and cover crop success, farmers are eyeing interseeders that will plant the cover crop beneath the canopy of the standing crop. For example, researchers at PSU have developed an interseeder implement and the team at Hagie Manufacturing has developed two seeding attachments for its high-clearance, self-propelled machines.

Multiple methods.  Hoover says PSU  researchers developed an interseeder that can perform up to three jobs at one time. This interseeder is designed for use in crops planted on 30" rows and features double-disk drill openers spaced 7.5" apart. As farmers plant, they can also broadcast postemergence herbicides beneath the corn canopy and apply sidedress nitrogen in a high-pressure stream about 4" off the row.

PSU researchers estimate that farmers can save between $20 and $30 an acre in labor, machinery and fuel costs by performing the three tasks at one time versus doing them individually.

Two common threads in interseeding cover crops are eliminating the challenge of planting into heavy corn residue and trying to be more efficient with each machinery pass.

Since 2012, Hagie Manufacturing has been working to develop a way to maximize its high-clearance machine with an interseeder attachment. So far, the company has come up with two types of systems. With the air boom version, the solution tank is replaced with an 80 cu. ft. dry box and the boom is rigged with the necessary tubing to broadcast below the crop canopy. The second system uses the Hagie nitrogen toolbar but replaces the coulters with seeding attachments and rolling baskets to incorporate the seed.

The company has worked with trials using ryegrass, radishes, sudangrass and several mixes.

"Interseeding machines provide farmers with a solution beyond aerial application," says Rachel Halbach, agronomist with Hagie Manufacturing. "In our small-scale trials we’ve seen greater stand establishment, even at lower seeding rates, when using an on-ground interseeder compared with an airplane."

The air boom broadcast system fits on a 60' or 90' boom. The retrofitted toolbar for interseeding is 40' wide.

"We are able to run 8 mph to 10 mph in standing crop," Halbach says. "So far, we think the more ground our operators can cover in less time, the more successful they will be using their machines for this operation."

In fact, she envisions cover crop seeding being another custom service Hagie operators can provide with their machines.

The timing of seeding cover crops is a balancing act—early enough for the cover crop to get established before winter but not too early that it impacts the corn crop.

One significant factor PSU researchers are still trying to establish is when to use the interseeder. So far, on-farm and experiment station tests conducted during the past three years indicate the ideal timing is just as corn reaches the V5 growth stage.

"The idea is to get the cover crop established, but not so early that it becomes competitive with the corn or other row crop," Hoover says. "On the other hand, the cover crop has to be able to survive two to three months of shade prior to corn leaves senescing and corn harvest."

Hoover says one thing that farmers will need to consider if they want to try interseeding is what cover crop species to select. The ideal crops can esta­blish quickly and then tolerate heat and shade under the corn or other row crop, followed with good fall growth and winter cover. Annual ryegrass, red clover, crimson clover, and clover/ryegrass mixtures have worked the best so far in PSU trials.

In Hagie Manufacturing’s research in Illinois, Indiana and Iowa, Halbach says they’ve interseeded as late as mid-September.

"There are a lot of variables that we know farmers need to factor in, including hybrid, weather and environment," she says. "Right now, my best recommendation for the Corn Belt is to be seeding by Aug. 15."

Hoover says PSU researchers are analyzing its interseeder’s ability to plant cover crops in soybeans but have limited experience with the crop so far.

"While many of our trials are conducted in no-till situations, interseeding could be a greater help to conventional or minimum tillage farmers, where the potential for erosion is likely greater," Hoover says.

To date, the PSU team has built several units up to six rows that employ the double-disk drill opener design. The team is now working with a manufacturer to produce units for commercial use. Hagie Manufacturing will have limited availability of its systems in the coming year. 

You can e-mail Rhonda Brooks at

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