Iowa plans to revise Iowa’s nitrogen fertilizer recommendations

Jeff Knupp harvests corn in September 2021 in rural Garrison. Iowa lawmakers need to spend $1 million subsequent yr to revise the state’s long-standing nitrogen fertilizer calculator utilized in seven corn-growing states. (The Gazette)

The Iowa Legislature needs to spend $1 million subsequent yr to revise the state’s long-standing nitrogen fertilizer calculator utilized in seven corn-growing states.

The cash could be used to replace the “static” Most Return to Nitrogen calculator with a “dynamic modeling system that considers variability within the setting, administration and climate,” in response to the Infrastructure Appropriations Invoice handed by the Iowa Home and Iowa Senate earlier this week.

Whereas two Iowa State College professors say they welcome extra analysis into the nitrogen query, some water high quality advocates worry revising nitrogen fertilizer suggestions will imply extra fertilizer utilized to fields and extra runoff into streams and lakes.

“It appears unlikely we’re going to be making use of much less nitrogen anytime quickly as a result of we all know the inputs exceed the suggestions now by a fairly substantial quantity,” mentioned Chris Jones, a UI analysis engineer who research water high quality.

“We find out about one-third of that surplus (nitrogen) leads to the streams. If we enlarge that surplus, it stands to motive the quantity of nitrate in our streams goes to extend.”

Chris Jones, College of Iowa analysis engineer

Practically 20 years in the past, a bunch of Midwestern soil scientists, together with Iowa State College Professor Emeritus John Sawyer, developed the Most Return to Nitrogen, a observe that requires weighing the costs of corn and fertilizer to seek out the candy spot of productiveness and revenue with out waste.

In addition they developed the Corn Nitrogen Price Calculator, a web-based device that lets farmers in seven Midwest states plug in native costs and get a fertilizer fee advice primarily based on scientific discipline trials of their space.

Farm Bureau criticism

Final summer time, the Iowa Farm Bureau criticized the strategy.

“Why is that specific device and that logic basically, why is that flawed and what’s a greater, perhaps extra knowledgeable method, of taking a look at this concern of nitrogen that in our soil, each naturally and what’s being utilized?” moderator Andrew Wheeler requested throughout the Spokesman Speaks podcast July 26.

Rick Robinson, Farm Bureau’s then-natural sources coverage adviser, responded: “Many soil scientists say that the long-standing MRTN fee calculator, which estimates the financial return to nitrogen software charges with completely different nitrogen sources and corn costs, actually doesn’t account for climate and soil variability or modifications and enhancements in genetics and administration that we’ve seen over time. That form of info hasn’t been up to date within the MRTN.”

In December, the Iowa Carbon Sequestration Process Drive proposed spending $1 million a yr for 10 years to replace the fertilizer calculations. The funding could be used to “conduct a number of a whole bunch annual trials to allow next-generation fertilizer administration …” minutes of the Dec. 6 assembly state.

Analysis welcome

The $1 million, if authorized, would go to the Iowa Division of Agriculture and Land Stewardship. However ISU school consider they’d be the eventual beneficiaries for discipline trial work.

“If we get the cash, what I can let you know, whether it is particularly for nitrogen, that may be nice,” mentioned Antonio Mallarino, an ISU professor of nutrient administration analysis and extension. “If the brand new analysis reveals there may very well be another method of suggesting optimum charges for corn earlier than planting, we’ll use it.”

Antonio Mallarino, ISU professor of nutrient administration analysis and extension

Mike Castellano, an ISU agronomy professor, mentioned the nitrogen fertilizer suggestions ought to be up to date as a result of they supply solely 4 fundamental suggestions for Iowa, averaging greater than 100 discipline trials performed over years.

“We need to attempt to make extra particular suggestions for various methods corn is grown, completely different soil varieties, completely different genetics and climate variability yr to yr,” he mentioned Wednesday.

“The rationale to replace the MRTN and put extra trials in it’s to find out the actual optimum charges so farmers aren’t simply making use of the common fee which may be very, very completely different above or under the precise.”

Mike Castellano, ISU agronomy professor

The Carbon Sequestration Process Drive minutes point out if farmers purchase much less fertilizer, there could be a discount in greenhouse gases from factories that make fertilizer. Aside from that, it’s unclear how lowering fertilizer software is said to carbon sequestration.

Lawmakers’ take

Sen. Kevin Kinney, D-Oxford, mentioned he helps the $1 million appropriation.

“They’re making an attempt to give you a extra exact system,” he mentioned. “They’re making an attempt to make use of much less (nitrogen).”

Rep. Chuck Isenhart, D-Dubuque, mentioned the price range appropriation got here “out of the blue” with out being mentioned in a legislative committee.

“A million {dollars} is an efficient chunk of change,” he mentioned. “We actually ought to be higher knowledgeable about what we’re voting on.”

If the state invests $1 million a yr to replace the nitrogen fertilizer requirements, the state ought to know what number of farmers are utilizing the N-rate calculator, whether or not farmers are following the really helpful quantities and what are the real-time outcomes by way of water high quality, Isenhart mentioned.

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