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Clay maps for potassium management: Help improve Minnesota’s fertilizer guidelines with soil samples from your county

By: Leanna Leverich, graduate research assistant, & Dan Kaiser, Extension nutrient management specialist

minnesota map soil samples
Soil samples are needed from the counties highlighted in orange
This spring, we blogged about our preliminary research showing how soil clay type maps could help Minnesota farmers. This research is well on its way to fine-tuning the university’s corn and soybean fertilizer guidelines, but first, we need more soil samples from around the state. That’s where you come in.

If you farm or work with farmers in one of the counties listed below, we would greatly appreciate your help taking and sending soil samples to us. These samples will help us to develop more accurate maps of Minnesota showing soil clay type, which will likely help determine the university’s suggested K rates for fields around the state in the near future.

We need soil samples from these counties in Minnesota:

  • East/Central: Wright, Anoka, Chisago, Mille Lacs, Washington, Eastern Hennepin, Kanabec, Carver, Scott, Goodhue (south), Winona (east), Filmore (southeast)
  • Northwest: Douglas, Todd, Otter Tail, Wadena, Becker, Norman, Mahnomen, Clearwater, Red Lake, Roseau, Kittson (north)
  • Southeast: Wabasha, Dodge, Houston, Rice, Blue Earth, Nicollet, Le Sueur (north)
  • Southwest: Watonwan and Martin
  • West: Big Stone and Traverse
If you are interested in collecting soil samples for this project, please contact Daniel Kaiser at or 612-624-3482.

We need around a cup of soil collected from a representative soil type in a county. The only information we need is the soil series, and, preferably, rough GPS coordinates for the area where the sample was taken. The samples will be dried and sent off to ACT Labs in Canada for analysis. We do not need any information about field practices.

Thank you to the Minnesota Corn Research and Promotion Council for funding this project and for providing the means to develop these maps for all producers.


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