2023 June Stewardship Advocate


The Iowa Nitrogen Initiative (INI) is a private-public partnership with a vision to provide Iowa farmers with the best nitrogen science in the world for the benefit of productivity, profitability, and environmental performance. The initiative is funded by both public and private dollars, with the bulk of the funding coming from the Iowa Department of Agriculture and Land Stewardship. The legislature has funded updates to Iowa’s nitrogen recommendations at a $1.0 million level in both fiscal years 2023 and 2024. Additionally, there has been funding from partner organizations, including Iowa Corn Promotion Board.           

Dr. Mike Castellano, Iowa State University professor of soil science and director of the Iowa Nitrogen Initiative says the solutions developed through this partnership will benefit Iowa’s farmers, the economy and the environment. “The INI is a dynamic program that, with close collaboration among farmers and scientists, will generate continuous improvement to ensure that Iowa remains a global leader in the efficiency of production. By placing nitrogen rate trials with farmers under real-world conditions, we are able to study and measure corn performance under numerous soil types, weather conditions and nitrogen rates.”

Melissa Miller, INI project director said the program has grown significantly in its first two years, “We had less than 70 trials last year and this year we have 270 on-farm trials on 148 fields, working with 72 different farming operations. The results of these trials will be shared in early 2024. We hope to have 500 trials next year in the 2024 crop year. We are actively recruiting farmers that have access to variable rate equipment to participate, and they can click here if interested in learning more.”

Several Iowa Corn grower leaders are participating in the project with their own on-farm trials. Kelly Nieuwenhuis who farms near Primghar has participated in the initiative for the last two years and says “The Iowa Nitrogen Initiative has been very easy to work with. I’ve done grid soil testing on both corn on corn, and corn following soybeans. Nitrogen application rates in the plots vary from 0 to 240 lbs. per acre on corn after corn and 0 to 210 lbs. per acre on corn after soybeans. I’ve learned so far that more nitrogen doesn’t mean more yield. In fact, when the nitrogen rate gets over our normal application rates, yields have mostly gone down. The value to me is knowing we can cut rates without sacrificing yield, and that organic matter doesn’t get enough credit for fertility values.” Kelly is looking forward to this year’s results to compare them to 2022.

Tim Burrack farms near Arlington and has had a similar experience as Kelly. “It is very easy to be part of this project. The nitrogen rate prescriptions of 0 to 160 lbs. per acre of N are sent to my monitor and I can plant the plot in a short amount of time. This trial will help me understand and improve my nitrogen use efficiency. In last year’s trial, 80 lbs. per acre of nitrogen was the optimum rate and I’m anxious to see the results in this year’s trial.”

Kelly and Tim are hosting field days in August sponsored by Iowa Corn, and both are excited to share their experiences and learnings from participating in the Iowa Nitrogen Initiative.

For more information on the Iowa Nitrogen Initiative, click here.

Figure 1. On-farm trial of several nitrogen rates
Figure 2. 2023 on-farm trial sites

Latest Information

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FARMER TO FARMER: Dr. Mike Castellano

Hear from Dr. Mike Castellano about the Iowa Nitrogen Initiative:

Upcoming Events

Multiple Days: Iowa Learning Farm Webinars, Webinar

July 19 – Relay Cropping Field Day, Spencer

Multiple Days – Research Farms Field Days and Meetings, Multiple locations

Multiple Days – Practical Farmers of Iowa Field Days, Multiple locations

Multiple Days – Coalition to Support Iowa’s Farmers Field Days, Multiple locations

July 26 & 27 –Midwest Construction Expo and Field Day, Melbourne

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