Nitrogen management: Two on-farm research programs offer Minnesota corn growers opportunity to improve N fertilizer practices

By: Dawn Bernau, Soil Scientist, MDA Fertilizer Field Unit; Mike Cruse, Soil Scientist, MDA Fertilizer Field Unit; and Jeff Vetsch, SROC soil scientist

This blog post was originally published July 2022

Have you been thinking about trying a new nitrogen management practice but you’re not quite sure how it will work for you? On-farm trials can help producers and crop advisers test and evaluate alternative practices on their own farms. The Nutrient Management Initiative (NMI) and Southeast Minnesota Nitrogen Rate and Timing Research Trials are two examples of on-farm research programs that help producers look at alternative nitrogen management practices.

Nutrient Management Initiative

The NMI program uses a simple approach to evaluate nutrient management practices that can improve fertilizer use efficiency and benefit water quality. Since the start of the program in 2006, over 730 on-farm trials have been conducted statewide in Minnesota. Producers have tested nitrogen rate after manure, nitrogen rate after alfalfa, nitrogen stabilizer products, nitrogen fertilizer source, and the use of cover crops. Nitrogen rate and timing of application continue to be the most popular trials chosen by producers.

There are multiple benefits to completing an NMI trial. Participants receive a final yield data analysis, a simple economic analysis, and data to help guide future nitrogen management decisions. In addition, producers and their crop advisers receive compensation for each completed field trial. The rate of compensation depends on the trial type and vary between $800 and $1,000. Basic trials compare a normal and alternative nitrogen practice, while advanced rate trials compare six nitrogen fertilizer rates.

Southeast Minnesota Nitrogen Rate and Timing Research Trials

In addition to the NMI program, the Minnesota Department of Agriculture (MDA) also supports the Southeast Minnesota Nitrogen Rate and Timing Research Trials. These trials look at the effects of nitrogen rate and application timing on corn production, nitrogen use efficiency, net return to nitrogen fertilizer, and residual soil nitrate. This work has produced powerful information for producers and has provided an opportunity for them to discuss future research needs with researchers.

Data from these trials have been used to calculate the economic optimum nitrogen rate (EONR) for different operations, and producer feedback has led to planned research changes. Over the next two years, trials will compare a full response curve of both single spring preplant and split-applied nitrogen, look at the effects of nitrogen stabilizers, and include more in-season soil tests to look at predictors of nitrogen response.

Improving nitrogen management in Minnesota

Producers, crop advisers, researchers, and the state of Minnesota have benefited greatly from these trials over the years. Producers have been able to better select their nitrogen fertilizer rates, which has improved their bottom line and protected water quality from controllable N losses. We have a better understanding of how weather, in particular rainfall from May to June, influences the need for different rates of nitrogen fertilizer from year to year. And there is evidence to show that we can reduce the risk of nitrate-nitrogen leaching to groundwater and surface water when there is an increase in the adoption of nitrogen best management practices (BMPs) in the region, such as applying nitrogen at rates near the Maximum Return to Nitrogen (MRTN).

In addition, the work done in these two programs helps support the corn nitrogen guidelines recommended by the University of Minnesota, and much of the data from these trials is kept in the database used for the Corn Nitrogen Rate Calculator. This calculator allows farmers to get a recommended nitrogen fertilizer rate for corn based on real-world data from Minnesota and their own specific prices for nitrogen fertilizer and corn.

Interested in participating?

The NMI program is managed by the MDA, while the Southeast Minnesota Nitrogen Rate and Timing Research Trials are managed by the University of Minnesota. Both programs are funded by the Clean Water Fund through the MDA. Registration for the Nutrient Management Initiative opens each year in January and closes either in March or when the funding limit has been reached.

Producers interested in the Southeast Minnesota Nitrogen Rate and Timing Research Trials can contact:

Jeff Vetsch
Waseca, MN
507-837-5654
jvestch@umn.edu

Producers interested in the Nutrient Management Initiative can contact:

Dawn Bernau
2118 Campus Dr. SE Suite 100
Rochester, MN 55904
dawn.bernau@state.mn.us
507-206-2881

Ryan Lemickson
23070 North Lake Shore Drive
Glenwood, MN 56334
ryan.lemickson@state.mn.us

Additional resources

• U of M Southern Research and Outreach Center (SROC) nutrient management research (this web page incudes videos and presentations on research obtained through the Southeast Minnesota Nitrogen Rate and Timing Research Trials)
• Results for the NMI and N Rate and Timing Research On-Farm trials (for reports dating back to 2009, refer to the Minnesota Digital Water Research Library)
• Interactive tool: Explore an on-farm corn research plot studying nitrogen economics in Minnesota

---

For the latest nutrient management information, subscribe to the Nutrient Management Podcast wherever you listen and never miss an episode! And don't forget to subscribe to the Minnesota Crop News daily or weekly email newsletter, subscribe to our YouTube channel, like UMN Extension Nutrient Management on Facebook, follow us on Twitter, and visit our website.