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Sponheim is making cover crops profitable

Article cover photo
Mitchell County farmer Dean Sponheim uses cover crops, no-till and strip-till to improve his soil and his bottom line. (Photo: Joseph L. Murphy/Iowa Soybean Association)

By Carol Brown, ISA communications specialist

Dean Sponheim is turning over his soil… in terms of quality, not by plow.

“I come from ground where they say we can’t grow anything unless it’s totally black — moldboard plow country,” said Sponheim, whose Mitchell County farm is 30 miles from the Minnesota border.

“When I was growing up in the 1970s, we were moldboard plowing. I’m not downgrading my ancestors by any means, it’s just what was done,” he said. “Things have changed today.”

A new era

Sponheim farms nearly 900 acres with his wife, Cindy, and son, Josh, growing corn and soybeans near Nora Springs. The family began strip-tilling in 2000. The first time, he strip-tilled only four rounds of strips and planted them the following spring.

“I couldn’t believe the difference. We didn’t turn back,” Sponheim said.

Sponheim acknowledges there are places in Iowa that aren’t conducive to no-till but believes strip-tillage could work in any situation. It is a happy medium between conventional tillage and no-till. In soils that are dense and slow to dry in the spring, strip-till exposes only the strips of soil where the seeds will be planted, to warm and dry quicker for planting. The system leaves residue over the rest of the field to protect it from erosion and to build organic matter as the residue breaks down.

For the Sponheims, strip-tilling became a step toward no-till.

“It takes a good seven or eight years to transition from strip-till to no-till; you could speed things up if a cover crop is added,” he said. “I thought I’d be strip-tilling for the rest of my life, but strip-till has become a tool for us to transition to no-till.”

They have converted their acres that have been strip-tilled for 20 years over to no-till, the ultimate goal for the Sponheims. No-till benefits include increased soil organic matter, erosion control, fuel savings as well as fewer passes across the fields.

He didn’t think his soils could handle no-till, but after it responded so well to strip-till the leap wasn’t difficult. Son Josh began farming additional land about four years ago and those acres also will be transitioned from strip-till to no-till when the ground is ready.  

Cover crops are a big deal

Cover crops entered the picture on Sponheim’s farm in 2012. He admits to several mistakes starting out. He said the first two years he tried it — 2012 and 2013 — were both very dry years.

“When I started with cover crops, I thought bigger was better. I planted a mix of five species of cover crops — expensive seed. I got nothing out of it,” Sponheim said. “My neighbors were raving about how well their cover crops were growing. I found out they were using only cereal rye, so I switched the next year.”

In 2014, he and a small group of producers went together and flew cereal rye seed into standing crops over 500 acres. It was successful, so Sponheim kept adding acres and even created a business out of it. Last year, Sponheim Sales and Service flew cover crops on 20,000 acres and drilled cover crops on another 7,000 acres for their customers.

Cover crops play a role in achieving the goals set in the Iowa Nutrient Reduction Strategy, Sponheim said.

“We will need 18 million acres with cover crops to help reach the strategy’s goals,” he said. “There isn’t enough seed to cover half of that, not even a quarter of that.”

Sponheim has seen an increase of farmers interested in planting cover crops in efforts to meet the goals of the strategy.  He started lining up seed from brokers to meet customers’ demands but wasn’t able to source enough seed. Now he contracts with growers in the area to grow cereal rye and oats for his business.

Today, Sponheim Sales and Service includes growing cereal rye and oats for seed, cleaning the seed and selling it to farmers and co-ops for them to mix in with fertilizer to bulk spread it. His business also makes arrangements for cover crop application, whether it’s by airplane, no-till drill or by inter-seeding. He recently expanded the company’s seed cleaning facility to help with the growing business.

The big picture

Sponheim sees the big picture when it comes to using cover crops. There are some small issues to overcome or manage for, but in the long run, cover crops can be beneficial to farmers.

“Cover crops are doing more good than harm, because of what they do to our soil,” Sponheim said. “There is usually twice as much growth underground as we get above-ground with rye, but that’s why it’s good for soil biology and sequestering nitrogen.”

He cautions those who may find cover crop management challenging to rethink their goals.

“Cover crops are not to take away from our cash crops. They are used to complement and improve our cash crops,” he said. “If they’re not doing that for you, something needs to change.”

Contact Carol Brown at

For media inquiries, permission to republish articles or to request high-res photos, please contact Katie James, ISA Public Relations Manager at © 2020 Iowa Soybean Association. All rights reserved.

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