Innovation Grant Spotlight: Evaluating variable rate nitrogen programs

Written by Jonathan Eisenthal

The 2018 Innovation Grant Program is underway, with 12 farmers receiving grants from Minnesota corn to lead projects focused on nitrogen management. Throughout the summer we will be highlighting ongoing projects focused on how to better manage nitrogen and protect water quality. To learn more about each completed and ongoing project, click here.

Today’s farmers are focused on nitrogen use efficiency to both limit expenses on the farm and prevent the loss of nitrogen to ground and surface water. Innovation Grant participant Les Anderson, who farms in Cannon Falls, is evaluating a number of Variable Rate Nitrogen programs to see if they effectively reduce the amount of nitrogen fertilizer needed per bushel of corn.

With GPS-derived mapping, tech companies have taken on the task of predicting nitrogen needs for plants. A host of services have cropped up, leaving the individual farmer with the guesswork of which one will work best. All of them to some extent combine soil sampling, computer-modeled weather forecasts and a deep understanding of the nitrogen cycle.

Anderson noted he used to apply his nitrogen in the fall, then went to a single spring application, and finally to side-dressing that split the nitrogen into a number of spring applications. Still, it’s always involved an element of guesswork and luck.

“We just didn’t have the technology to fine tune it the way we do now. Now you can place your N at the right time, the right place, the right amount, the right form,” Anderson said.

consultant, Todd Anderson, an agronomist at Ag Partners Co-operative in Goodhue, is overseeing the nitrogen application in the plots.

Todd Anderson said while the Climate Corporation model uses a combination of soil tests and weather modeling, Adapt N is looking at organic matter and a little bit at the cation exchange capacity. Advanced Yield System makes recommendations based on soil nitrate tests. The results of each are set into a grid map that the sprayer’s computer uses to adjust the flow of the nutrient as needed.

The generic side-dress amount was a flat rate of 80 pounds of nitrogen per acre. This was on top of 60 pounds of nitrogen put out at the beginning of the season. Climate Corporation’s model suggested raising the side-dress to 111 pounds, while the other two said less than 80 pounds would be needed. In some spots it advised no additional N.

“These services are a bit spendy, coming to about five to ten dollars an acre—doesn’t sound like much, but when you multiply that across the whole farm…it will be very interesting to see which predictions really work out.”

The effectiveness of each program will be known based on yield results during harvest. Follow along for the results of Anderson’s project at mncorn.org, as well as on Twitter (@mncorn) and Facebook (@MinnesotaCorn).

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