Originally written By Whitney Baxter
Iowa State researchers are working alongside farmers to discover the optimum rate of nitrogen to apply to fertilize fields and to develop a new tool to aid in that process.
Why it matters
The Iowa Nitrogen Initiative was established in 2022 thanks to funding from the Iowa Department of Agriculture and Land Stewardship and other entities. The group’s unique research approach combines data from hundreds of on-farm trials to determine the ideal amount of nitrogen fertilizer likely to result in the highest yields for each field.
Think of it as the Goldilocks, or “just right,” amount – too little nitrogen results in lower yields, and too much nitrogen means unnecessary funds put toward farmers’ second highest input cost (behind seeds).
“We want to understand the variability of nitrogen and understand what practices can be used to improve efficiency,” says Mike Castellano, professor of agronomy and INI project lead. “We’re trying to reduce the risk of over application.”
New tool available
With their extensive dataset, the INI team collaborated with farmers to create N-FACT (Nitrogen Fertilization Application Consultation Tool). This free, online tool allows farmers to input information specific to the field they’re planting, including expected precipitation, post-harvest soil nitrate rate and planting date, to determine an optimum nitrogen amount. Farmers can experiment by entering different information for that same field to see how variations impact the suggested rate.
“There are lots of scenarios to explore,” says Sotirios Archontoulis, professor of agronomy and INI co-principal investigator. “It gets them thinking about things they might not have before.”
Get involved
The team is always looking for more farmers to become involved. The only requirements: the farmer must apply nitrogen at a variable rate and have a combine yield monitor.
“It requires little effort on their part, and they don’t have to change practices. In return, they get a lot of very practical information,” says Melissa Miller, INI project director.
For example, certain field sections are selected to have different nitrogen rates applied. The yield outcomes from those trial areas are compared to those from the rest of the field, resulting in an improved estimate of the optimum nitrogen rate.
Andy Petersen farms in Jones County, Iowa, and says last year’s data showed his field’s optimum nitrogen rate could be higher, so adjustments were made for this year’s application.
“It’s important to make sure the crop is using nitrogen to its fullest and not ending up in drinking water,” Petersen says. “I’m excited to see if we get a good growing season this year.”
To sign up for the field trials, fill out the Iowa Nitrogen Initiative Trial Interest form.
