Northfield farmer Sam Peterson joined the Minnesota Corn Innovation Grant Program in 2017 to research the economic benefit of variable-rate nitrogen (VRN) programs. While Peterson and his dad, Bruce, had started embracing these programs, it was difficult to determine the return on their investment.

Peterson was familiar with the variety of VRN programs, all of which tout the same benefits but use different methods to get there. With that, he tested out three of the more prominent brands—Central Advantage’s Nitrate Now, Winfield Solutions’ R7 Tool, and Encirca—on three different fields. The objective in testing each was to make a financial comparison between the three to determine which variable rate treatment, if any, is most profitable when compared to a flat rate treatment.

“We wanted to try and tackle this in a way that will get some real data to show how each are different,” Peterson said. “Each will affect your yield and they all cost money, so we wanted to find out which is going to get your money back.”

During the 2017 growing season, the yield difference between the VRN programs and flat rate did not produce a statistically relevant difference. For his second year of trials, Peterson chose fields that were more variable with hills, thinking these fields would best benefit from variable rate application. Combining that with a high-response hybrid corn seed, and Peterson uncovered the statistical difference that was not present in year one.

Winfield’s R7 tool brought a nine-bushel increase in yield, which led to a $16.87 net profit per acre compared to the flat rate trial. With the high amount of rainfall during the 2018 season, Peterson estimated the added precision in nitrogen placement was vital in maintaining high yields.

One of the ways R7 and other VRN programs recoup the initial investment is by decreasing the total amount of nitrogen applied on a field throughout the year by varying the amount based on the field’s production. With less nitrogen applied in areas where it is not needed, less is available for run-off, producing a key environmental benefit.

“We are decreasing our total nitrogen use, and we are also bumping up our yields because these programs know what area needs the nitrogen. Overall, it has been huge in helping out our overall yields at the end of the year,” Peterson said.

 Peterson will continue his project for the 2019 growing season. You can check back on his progress and updates on other Innovation Grant Program farmer-led projects at mncorn.org/research.