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4R Plus field day builds relationships and knowledge

Article cover photo
Scott Nelson, Director of the On-Farm Network, presents during the 4R Plus field day earlier this week. The 4Rs of nutrient management involve applying the right source, at the right rate, at the right time and in the right place. (Photo: Joseph L. Murphy/Iowa Soybean Association)

By Carol Brown, ISA environmental communications specialist

The 4Rs of nutrient management — the Right source, at the Right time and the Right rate, at the Right place — along with conservation practices were the focus of a day-long event at the Iowa State University (ISU) Field Extension Education Laboratory (FEEL) farm near Boone.

More than 80 attendees heard from six presenters on topics ranging from nitrogen management and variable rate application, phosphorus and potassium management, soil erosion reduction and more. The event was hosted by the Iowa Soybean Association (ISA).

“We were able to gather agronomists, scientists and farmers together to discuss how to manage crops more sustainably,” said Scott Nelson, ISA’s On-Farm Network® director. “Relationship-building between these groups is just as important as sharing new management practices and technologies that farmers can implement to improve water quality and reduce soil erosion.”

Nelson organized the event and presented on the 4Rs of nitrogen management.

“There is some tremendous new research on how to optimize sources and placement of nitrogen to increase yield in corn production. We reviewed this new data in our session,” Nelson said.

Southwest Iowa farmer Steve Killpack spoke to attendees about variable rate nitrogen.

“I like to call it nitrogen optimization. It sounds more like we know what we are doing opposed to just applying nitrogen randomly all over the field,” said Killpack.

He is a corn-soybean farmer but doesn’t limit himself to that label.

Killpack said he's a businessman. He likened farming to producing "widgets" with X amount of money for inputs and selling them at a profit.

“I want to remove as many variables in this equation as possible to make the most profit," he said. "To make money, you either have to increase population or allow the plant to produce to its full potential.”

Killpack talked of the correlation between variable rate application and a yield monitor.

If yields vary across the field, nitrogen application needs to correspond with areas that aren’t performing as well. Avoid blanket application, he said.

“I can’t control the weather, but I can control soil health to some extent," Killpack continued. "I can control inputs such as population counts and proper nitrogen application amounts where the plants need it most."

Slowing soil erosion

To go along with elements that farmers can and can’t control, Rick Cruse talked about soil erosion. Cruse is a professor of agronomy at ISU and leads the Iowa Daily Erosion Project.

Iowa’s average soil loss is 5.8 tons per acre per year, according to the Natural Resources Conservation Service (NRCS), just a bit higher than the tolerable level of erosion set at 5 tons. Cruse’s message is that this loss is unsustainable, and that Iowa is actually losing much more than this, especially after the heavy rain events the state is seeing.

“The Daily Erosion Project website shows how much erosion is taking place as it considers ephemeral erosion, which the NRCS doesn’t consider in their calculations,” said Cruse.

Ephemeral gully erosion includes water runoff channels that appear during a rain event and are usually filled by tillage. But they reappear after the next rain event or season in the same places.

Cruse said the best way to slow erosion in agriculture is through no-till and grassed waterways.     

Dean Sponheim discusses his first time experiences with no-till and strip-till during the 4R Plus Field Day earlier this week. (Photo: Joseph L. Murphy/Iowa Soybean Association)

Learning about tillage systems, cover crops

Dean Sponheim, ISA member and farmer in Mitchell County, talked about strip-till, no-till and cover crops and how they can be used in northern Iowa.

“A lot of people say that we’re too far north to use these practices,” said Sponheim. “But I’ve been strip-tilling for 18 years. I’ve been called the ‘accidental conservationist,’ because I didn’t make these changes for environmental reasons. The conservation benefits are a happy side effect.”

Sponheim said that he could talk for days about moving to strip-till and no-till; it’s that important to transition correctly.

“You can’t go directly from conventional tillage to no-till. It just won’t work. Your soils are not ready,” continued Sponheim. “It took seven to eight years for us to see the full benefits of strip-tillage.”

He also spoke of adding cover crops to his operation. Sponheim struggled with getting cover crops established — 2012 was his first year to try them, only to face drought conditions.

“I had purchased an expensive mix of seeds, only to watch them fail. Not being a quitter, I tried again the next year with the same mix,” he said. “By the third year, I took the suggestion of other farmers in the area using cereal rye and found success.”

He now runs a cereal rye seed business, with 13 cooperators growing rye and oat seed, along with his 800 acres of cereal rye and 400 acres of oats. He and his son manage the seed harvest, cleaning, and contracts for application either aerially or drilled.

4Rs Plus more ‘Rs’

Roger Wolf, director of ISA’s Environmental Programs and Services, provided attendees more R-words to add to the nutrient management list.

“We need to be making these farming decisions for the right reasons,” said Wolf. “The other R-word to consider is relationships. We can’t be successful with the Iowa Nutrient Reduction Strategy and avoid another R-word — regulation — unless everyone works together for the same goals of sustainable farmlands and for clean water in addition to making a profit.”

Carol Brown can be reached at:

For media inquiries, please contact Katie Johnson, ISA Public Relations Manager at or Aaron Putze, ISA Communications Director at

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