Iowa Nitrogen Initiative unveils decision-making tool for more informed fertilizer use on the farm.

A new online nitrogen fertilizer application consultation tool (N-FACT) that helps Iowa farmers make informed nutrient application decisions during the growing season was unveiled at the Iowa Ag Expo last week in Des Moines.

Launched by the Iowa Nitrogen Initiative (INI) and led by Iowa State University (ISU) in partnership with multiple public and private organizations, the tool factors in various field-level production variables and recommends an optimum range of nitrogen application rates. The goal is to help farmers balance productivity, environmental stewardship and input costs.

Iowa farmers can explore on-farm rate trials online, input key data to determine their optimum nitrogen rate and compare scenarios if conditions change. 

The N-FACT tool leverages thousands of data points from hundreds of field trials, which include factors such as field location, weather, residual soil nitrogen, estimated planting dates and input and commodity prices. These trials, conducted across Iowa, have produced more than 21,000 possible nitrogen rate scenarios.

Iowa Department of Ag­­riculture and Land Stewardship (IDALS) Secretary Mike Naig called the tool a game-changer for Iowa’s corn growers.

“This customized, field-level data provides valuable insights to help farmers make more informed crop management decisions. While responsible input management is always important, it is especially critical in this soft ag economy,” Naig said. IDALS is a funding partner in the project.

INI Project Director Melissa Miller said N-FACT serves as another “tool in the toolbox” to aid farmers in improving nutrient efficiency across Iowa’s farm fields.

The tool's development is the result of multiple years of in-field trials coordinated by INI, with support from hundreds of volunteer farmers. These trials gathered management data that impacts optimum nitrogen rates, including cover crops, residue removal, planting dates, tillage and drainage.

Studying nitrogen application rates across different farms and fields allows for more precise recommendations.

“This is very exciting for us to be able to have developed something that the public can use to interface with the research that we’ve been doing over the last two years outside of the 150 farmers that we work with every year,” Miller said. “Iowa farmers are some of the most efficient farmers in the world with nitrogen use.

“This tool is a resource for you to use and incorporate into all you already know about nitrogen in your soil, on your farm, because every farm, every acre is different.”

Initiative's efforts

The INI has partnered with agricultural service providers, farmers and advisors in this first-of-its-kind public-private partnership, deploying hundreds of on-farm, scientifically rigorous small-plot nitrogen rate trials. 

Optimum nitrogen application is critical for both farmers and the environment, Miller said.

“This is something that started five to six years ago as a way for the university to give better management recommendations than what currently exists,” Miller explained. “What’s different about our tool is that it’s backed by hundreds of on-farm nitrogen rate trials we’re conducting through the Iowa Nitrogen Initiative.”

The INI continues to expand its trials each year, adding more data points for the N-FACT calculator to refine nitrogen application rate recommendations.

“We can take these on-farm trials and what we’ve learned from them and teach the model to be better at getting the correct prediction for the optimum nitrogen rate,” Miller said. “This is only version one, and we have a huge amount of things to continue to learn and to be useful. We’re rejoicing that we have six inputs …, but there are hundreds more. We’ve barely just scratched the surface.”

Alan Atwater, a farmer from Manchester and an Iowa Corn Growers Association member, said nitrogen fertilizer is one of the biggest expenses for Iowa corn farmers. 

“I had the opportunity to evaluate N-FACT during its development and was impressed with the data it presented,” he said. “This tool will allow farmers to better manage their nitrogen rates, allowing for better land management, lower input costs and improved nitrogen use efficiency.”

Daniel Robison, dean of ISU’s College of Agriculture and Life Sciences, praised the collaborative effort advancing the INI on behalf of farmers. 

“This tool is the latest advancement in productivity, profitability and environmental performance,” Robison said. “This is a big part of the future of farming, at every scale, and it’s beyond great that Iowa is leading.”

Field trials continue

The INI’s research is ongoing, with ISU set to conduct additional field trials during the 2025 growing season. 

Any Iowa farmer who can apply variable-rate nitrogen and has a combine yield monitor is invited to participate. Enrollment is open year-round.

To enroll in the field trials or learn more, contact Miller at millerms@iastate.edu.

ISU plans to release updated versions of the N-FACT tool as additional research and data become available.

To try N-FACT, visit https://n-fact.ag/start. A demonstration video is available at https://www.agron.iastate.edu/portfolio/iowa-nitrogen-initiative/.