Joe Dunn admits he loves to look out across his fields and see green, no matter what time of year.

Corn and soybeans during the spring and summer growing season followed by cereal rye during the late fall and early spring keeps the landscape colorful. To Dunn, a Warren County Farm Bureau member, there’s nothing better.

“Green is my favorite color,” he said with a chuckle. “To me, it’s valuable putting rye on cornstalks.  I know that green is slowing down erosion … building biomass … and you can just see the tilth.

“Our ability to drain water is way better than it used to be … and the soil just feels good and looks good when you take a shovel out there and flip it over.”

It’s an excellent feeling to know he’s doing his part to preserve the land and make it better.

“If you want to save your soil for future generations and the future world, it’s a no brainer,” he said.

Decade worth of benefit

It was roughly 10 years ago that Dunn’s son-in-law, Aaron White, approached him with the prospect of seeding cereal rye after harvest to build soil health.

“He’s big into trying things and thinking outside the box,” Dunn said.

Over the past decade, they’ve worked together managing a few thousand acres that include corn, soybeans, peas for Birds Eye and even 10 acres of sweet corn, along with Aaron’s small cow herd.

They have experimented with multiple cover crop options, including turnips and oats, but have settled on cereal rye as the best choice, harvesting their own seed each year from 15 to 20 drill-seeded acres to fly on roughly one-third of their acres Sept. 1 each year. The results have been undeniable.

“We grow it over here and then fly it on over there,” he said motioning from west to east.

As for soil erosion benefits, Dunn said, “You don’t have to see it; you know it’s happening because if you get a 5-inch rain, it’s not going to wash away.”

Cereal rye’s roots create pathways for water infiltration, and the biomass is feed for earthworms, which are beneficial to the soil.

“Rye is just a tremendous product,” Dunn said. “It’s got the biggest root ball of any plant.  There’s more root mass in the soil.”

Dunn has seen the benefits of weed suppression and points to increased yields as well.

“The way to make yield is organic matter, and that’s how you build organic matter is having the soil alive year-round, not just for four months,” he said. “Yields have come up a little because of the ability to hold more water.”

Planting into green

Managing cover crop implementation can be tricky, Dunn admits. No two years are the same, depending on the weather, forecast and time of year.

For example, by mid-April he and Aaron had “planted green” on 700 acres of corn and soybeans, opting not to terminate the rye yet because of favorable planting conditions.

“It’s (mid) April, the soil conditions are good, the forecast is good — we’re going to plant,” he said. “Those are the three things I’m looking at. We’re not going to worry about spraying the rye … it’s small and it’s not competing with the soybeans. We’ll come back later.”

Next year could be a different scenario, he said. Wet conditions following repeated rains could mean delayed planting, so they may opt to terminate earlier than originally planned. “We can go in and spray several days sooner than planting,” he said, “because it could get away from us and be a little harder to kill.”

In general, they look to plant into green cover crops to get the most out of the cereal rye and build soil health, Dunn said.

“Two years ago I terminated it early and then thought, you know, I just didn’t get the true benefits from that,” he said. “So it all depends. Determining when you’re going to spray year-to-year is different.”

Consider cover crops

Iowa State University Extension Field Agronomist Meaghan Anderson and Cropping Systems Specialist Mark Licht said many farmers are showing interest in cover crop implementation.

Those who have seeded for multiple years are finding their comfort zone while testing various cover crops, application methods and termination periods. There are soil health benefits to delayed termination.

“Delayed termination of cover crops allows for more biomass accumulation, which usually translates to more benefits for the soil,” said Anderson.  

Additional above-ground growth can be beneficial for raising cattle, suppressing weeds or building organic matter.

Added Licht, “Planting soybean green into a cereal rye … the biggest benefit is being able to use the cover crop for weed control.”

Both Anderson and Licht said cover crop benefits are measurable.

“Cover crops reduce nitrate losses from soil, reduce soil loss from erosion, can provide weed suppression, build organic matter, improve water infiltration into soil (and) increase water holding capacity of soils,” said Anderson.

There are the benefits of overall soil health and microbial diversity in the soil, too, added Licht.

“And let’s not forget reducing nutrient losses is a big social benefit,” he said.

Dunn advises farmers who want to begin cover crop implementation to start small and contact the NRCS (Natural Resources Conservation Service) to learn about available funding.  “You can get $3,000-$4,000 easily to offset the cost,” he said.

“That’s probably the number one thing why people don’t want to try cover crops is they don’t want to pay any more money.”

Licht suggests talking to neighbors and starting with cereal rye ahead of soybeans and oats ahead of corn. “Then slowly move to cereal rye ahead of corn and soybean,” he said.

Anderson added, “Look for opportunities to cost-share, start with a small acreage, … terminate cereal rye in a timely manner in the spring and make sure your planter is set up well to get through the residue.”