Frank Moore believes a little trial and error on his farm can go long way, and that led him to switch over to strip-tilling corn and introducing cover crops on his 2,000 acre farm near Cresco in northern Iowa.

Moore moved from ridge till to no-till in 2002, and in 2010 he began strip-tilling corn with a 16-row Kuhn-Krause Gladiator unit. The move from strict no-tilling was prompted by Moore’s concern about stratification of nutrients near the soil surface and he wanted more targeted application of phosphorus and potassium.

To further preserve and enhance soil health, Moore also introduced a variety of cover crops into his strip-till system. He has found that using covers on his strip-tilled fields with slopes greater than 6% has been effective in fighting back the erosion during heavy rainfall.

Some cover crops worked better than others, and he offers some advice about selecting varieties, seeding strategy and the expected return on investment.

Timing And Seeding

Moore began incorporating cover crops into his strip-till system 2 years ago. He says that there are some significant barriers to successful use of covers due to his shorter growing season in his location near the Iowa/Minnesota border. But this hasn’t stopped him from experimenting.

EROSION CONTROL. Experimenting with cover crops in strip-till, Cresco, Iowa, farmer Frank Moore finds that annual ryegrass works well because he gets about 4 inches of top growth and root structures 30 inches deep to help hold soil in place. Photo courtesy of Frank Moore

“We usually harvest in early October, but we need to have our cover crops seeded around the middle of September or earlier so that limits us to mostly aerial application,” says Moore.

He notes that there are a few exceptions to this. In Moore’s area there are a large amount of dairy farmers, and when they chop silage they can still get out in time to drill or broadcast cover crops. Another exception — although it’s certainly one Moore doesn’t want again — is a prevented-planting year.

“In 2012 we had a lot of prevented-planting acres up here, so the fields were bare in July and August,” he says. “But we were able to get in there early with a drill for the cover crops. That year was an exception that I hope never repeats itself because the fields were bare without having a crop planted.”

In the southern part of the Midwest, the potential exists for more ideal conditions. Moore came across a farmer in Southern Illinois who had fitted a Gandy air seeder on his soybean header and seeded the cover crops while harvesting in mid-October.

“It’s a pretty slick way of doing it, because the ground is bare and he’s seeding the cover crop as the combine goes over and spreads the plant material out the back,” says Moore. “It’s ideal for his area. But as far north as I am, even if I had that machine on there, that’s just too late to be seeding my cover crops.”

Being restricted by his cool, wet soils and short growing season, Moore has picked up a few tips that helped improve his seeding timing. He recommends aerially seeding the cover crops just as soybeans start to yellow but before they drop their leaves.

“For one thing, light penetrates the canopy down there, which is needed, along with moisture, to germinate those seeds,” says Moore. “I don’t want the leaves dropping off the soybeans because if I spread cover crop seed over that, and the seeds rest on top of leaves, they won’t germinate. So that’s the best thing for timing this far north.”

Selecting A Variety

Moore stresses that selecting the right cover crops for strip-till depends on a farmer’s goals. A dairy farmer looking for a cover crop to double as forage may look at different species than a strip-tiller with an eye on nutrient retention.

“My priority with cover crops is erosion control. Secondary to that would be to hold the nutrients in place, and third is to work in some weed control,” says Moore. “I think we’re going to see our cover crops suppress some of the early weed growth in the spring.”

With those goals in mind, Moore finds that annual ryegrass works well for him. He gets about 4 inches of top growth and root structures 30 inches deep to help hold soil in place. Ideally, much of his annual ryegrass winterkills, saving him the effort of having to kill it himself in the spring.

“Last year all my annual ryegrass, except for the end rows, winterkilled, which I loved because I didn’t have to kill it with an herbicide,” Moore says. “I would’ve had to wait for the ryegrass to start growing again for it to even absorb the herbicide — that would have pushed me into a situation where I’d have to plant later and lose yield potential.”

He doesn’t expect that annual ryegrass will always winterkill completely, and he’s still on the lookout for a variety that will, while still providing the same benefits.

In his experience with annual ryegrass and cereal rye, Moore notes distinctions in the growth and lasting effect on corn plants. Cereal rye gets taller and needs to be killed or controlled in the spring. It also can have an allelopathic effect on the corn the following year, where annual ryegrass shows little to none of this. There are also differences in his seeding strategies, with annual ryegrass being only about 26 pounds per bushel and cereal rye at about 56 pounds.

“Cereal rye seems to be the one that new guys are trying first, and it can get fairly tall in the spring,” says Moore. “The last 3 or 4 years up here, the first thing we did in the spring was plant corn into our strip-tilled fields, and there was absolutely no window to do any spring field operations or spraying.

“With cereal rye I’d need to kill it off in the spring and then wait a period of 5 days to a week before I’d want to plant. That can delay planting to a point that’s unacceptable in certain years.”

Trial And Error

Moore’s experiments with some other cover crops have seen varying results. During his prevent plant year he drilled some radishes into his strip-tilled fields. In the fall they were getting large and looked healthy, but by spring they were completely gone, which can help retain nutrients in the soil, more so than provide erosion control, especially on their own.

RADISH RETURNS. During a prevent plant year, Moore drilled radishes into his strip-tilled fields, which helped retain soil nutrients. However, Moore may combine radishes with another type of grass to provide a spring cover and offer more erosion control. Photo courtesy of Frank Moore

“I went out in the radishes in the spring to see how they were and they had totally disappeared,” says Moore. “Radishes have their place, but if I’m looking for something that’s going to provide cover into the spring, they’re not going to work. They may work in a mixture with some type of grass, but it all depends on what your goals are with your cover crop.”

There are a few barriers that Moore faces as he continues incorporating cover crops into his strip-till system. Again, being limited to mostly aerial application, cost is a consideration.

“Airplanes are nice, but when you start throwing in the seed and the airplane you are looking at a minimum of $20-$30 an acre as a starting point,” says Moore.

He is hopeful that it won’t be too long before he’ll be able to use other equipment to seed. “Some of the sprayers and pieces of equipment that are being developed might make it possible for us to start applying seed on the ground rather than from the air,” says Moore.

Another hitch is the elusive nature of the return on investment with cover crops. Moore feels that looking at cover crops as part of an overall strategy may be more beneficial than examining it them in terms of exactly how much they will increase yields.

For example, Moore’s cover crops have offered significant protection from erosion during event storms on his strip-tilled slopes over the past few years.

“I don’t want to plan for yield averages anymore,” he says. “I feel that these event storms are becoming more common and cover crops have definitely helped against the erosion I would have faced otherwise.

“There are a lot of intangible benefits to cover crops in strip-till. I think I can improve soil health, soil quality and reduce erosion and all those factors will eventually lead to better yields, but it’s not going to happen overnight.”