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Seeding Cover Crops

By Jessie Scott

Seeding is one of the most important aspects of cover crops, says Jason Webster, Beck’s Hybrids Practical Farm research director in Downs, Illinois. “I have to get the cover crop established and get it growing,” he says.

Beck’s Hybrids is in its fourth year of researching cover crops. The seed company isn’t alone. The USDA, universities, farmers, and additional ag companies are testing cover crops to discover the economic benefit, the impact on soil health, and the best way to incorporate cover crops into different crop rotations. The latter depends primarily on seed selection and seeding methods.

Ten years ago, the seeding options for cover crops were limited primarily to a drill. The recent explosion in cover crops has led to myriad seeding innovations, each with its own advantages and challenges.  

Drill
If you’re going in after wheat harvest to seed cover crops, a drill is a great option. You can get the seed established early enough so it has time for sufficient growth before winter sets in. For best growth, most seeds should have at least four weeks to grow before the first frost.

Drilling also tends to be a low-cost option. A no-till drill will cost about $7.80 an acre to run, according to Iowa State University. Recent auctions with 6- to 8-year-old 30-foot drills have brought between $26,600 and $30,500. Going back further in model year brings better deals. The price range for 12- to 16-year-old drills is $17,000 to $21,500.   

Joe Breker from Havana, North Dakota, has taken drilling one step further by doing what he calls bio strip-till. With an Amity single-disk drill, he plants peas on 30-inch centers and turnips and radishes on 30-inch centers, where he’ll come back and plant his corn. Breker plants the bio strip-till combination after he harvests winter wheat.

Unfortunately, using a drill doesn’t work nearly as well in a corn-soybean or corn-after-corn rotation. “When we drill in the fall, we have to wait until we get the crop off,” explains Webster. “We just have too short of a growing season.”

The exception to this is southern regions with warmer falls and springs, like Vincennes, Indiana, where Ray McCormick farms.

McCormick started using cover crops in the 1980s, stopped after a few years, and then jumped back on the cover crop bandwagon about eight years ago. “When I got back into cover crops, we were using a 30-foot drill,” says McCormick. “It was really effective and got great stands. But my son had to drill every acre as we were harvesting. It was a lot of sacrifice to have somebody drilling.

“I kept thinking,” he adds, “if we could do it with a combine, how would we do it?”

Air seeder
McCormick, like other inventive farmers, found the solution in an air seeder.

He mounted the air system to his combine head and installed hoses below the head right at the snapping rollers. “We are blowing the seed forward, so it’s ahead of the mulch coming through the head,” explains McCormick. “The combine head is laying a protective mulch on top of the cover crop seed. This helps the seeds germinate and establish a great stand.”

McCormick is using a Gandy Orbit-Air 62DS on his corn head and a low-profile Gandy Orbit-Air 62DS 1018 on his grain platform. Both run off a 12-volt drive. Each air seeder has a 10-cubic-foot capacity, allowing him to seed about 15 acres at a time.

To harvest more acres between refills, upgrade to a larger air seeder or install two on your combine head. McCormick recommends using a smaller-seed cover crop to increase acres per fill.

Gandy now makes air seeders specifically to install on combine heads or on tillage equipment, so you can seed while you perform fall tillage. Air seeders range in price from about $7,000 up to $21,000, depending how the unit is driven and the capacity.

High-clearance sprayer
Throughout most of the Corn Belt, seeding cover crops in the fall can be too late. If this is the case in your area, your best bet is to establish cover crops before harvest. One option is to use a high-clearance sprayer with an air seeder.

For the past two years, Beck’s Hybrids Practical Farm has tested a prototype system from Hagie Manufacturing. The liquid tank was removed from a high-clearance Hagie STS10 sprayer. A Gandy dry box was put on to hold cover crop seed and to move seed through the boom system where it drops through hoses that hang in between 30-inch rows.

“All I need is one rain to get the cover crop to germinate and to start growing,” says Webster. “Then, we remove the crop at harvest and let a lot of sunlight and air in so the cover crop can take off.”

Webster recommends seeding cover crops after pollination and when the corn starts to go through the senescence process.

The amount of acres you can cover in a day will vary depending on boom size, how much seed you can hold, and your seeding rate. A sprayer with a 60-foot boom, running at 8 to 10 mph, applying a smaller seed mix applied at about 25 pounds per acre can cover hundreds of acres in a day, says Webster.

Hagie’s Cover Crop Interseeder can be retrofitted to 2007 and newer STS sprayers. The seeding system includes an 80-cubic-foot Gandy dry box and works with 60-, 80-, and 90-foot booms. Base price for the system is $50,000.

Airplane
An aerial application is a low-maintenance option for applying cover crops. A local applicator can seed cover crops in late summer or early fall when you’re busy preparing for harvest.

Jamie Scott from Warsaw, Indiana, started using cover crops on his farm about 10 years ago.

“I am far enough north that I can’t wait until after harvest to get the cover crop started,” he says. “I started looking at other ways to seed, and that’s when I found airplanes. For me, it’s the cheapest, most effective way to put it on.”

In the beginning, Scott worked with a local applicator to seed cover crops on his farm, then on his neighbors’, eventually growing to a full-scale business. Last year, Scott coordinated the seeding of 50,000 acres. The cost of the airplane and seed is about $30 per acre.

“I fly-on cover crops in southern Michigan and northern Indiana the last week in August through mid-September,” Scott explains. “Seeding varies a little from year to year. It doesn’t matter as much about leaf stage as you often hear. It is more about moisture – planting the cover crop, getting a rain, and getting the cover crop to start growing.”

Smaller seeds need less moisture to germinate and may be a better option for aerial applications, advises Shannon Osborne, USDA-ARS research agronomist in Brookings, South Dakota.

“Mother Nature has to cooperate,” says Scott. “You have to catch a rain. If you drill, apply with a high-boy sprayer, or apply with an airplane, you will have that issue.”

Researchers tired of depending on unreliable Mother Nature created a new seeding method that helps seeds germinate by achieving better seed-to-soil contact.

Interseeding
Agronomists at Penn State University developed the Interseeder to encourage more farmers in the Chesapeake Bay watershed to plant cover crops.

The Interseeder can plant cover crops between rows of corn and, at the same time, spray a postemergent herbicide and apply fertilizer to help establish the cover crop. The Interseeder goes in corn that is approximately 12 to 20 inches high in late June.

The team decided to license the technology from the university and to start a company called Interseeder Technologies to help commercialize the idea. A Pennsylvania manufacturer is building the machines, which sell for $25,000 to $40,000.

Interseeding is the general term used to describe going into standing corn or soybeans and putting in cover crops. Beyond sprayers, airplanes, and the Interseeder, interseeding can be accomplished with fertilizer applicators and robots.

Osborne and her team added disk coulters to a fertilizer applicator, which cost about $5,000, so it can plant cover crops in between corn or soybeans. “We are looking at how this affects yield, growth of cover crops, and water use,” she explains.

Rowbot, a 2×7-foot diesel-powered, articulated robot, can interseed cover crops in standing corn as well as apply nitrogen fertilizer. Rowbot will have limited availability in 2015. A field service team will use the machines to sidedress for $10 an acre and seed cover crops for $15 to $20 an acre.

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