What Is a CPI Rating? How Southeast Minnesota Farm Soils Are Scored (and Why Tillable Acres Matter)

By Jennifer Busch, ALC | United Country Real Estate | Midwest Home & Farm Realty

If you've looked at a farm listing or an auction brochure in Dodge, Olmsted, Fillmore or Winona County, you've seen a number like "92.1 CPI" near the top. Buyers watch it closely. Sellers sometimes aren't sure what it means or where it came from. Whether you farm outside Kasson, work at Mayo Clinic in Rochester and inherited a family farm, or are just starting to look at land, here's a plain-English guide.

The short answer: CPI is the Crop Productivity Index, a 0 to 100 score for how well a soil can grow row crops, especially corn. Higher means more production potential. It's a useful guide for comparing farms, but it isn't a yield guarantee or a price, and it only means something when it's measured on the tillable acres.

Key takeaways

• CPI runs from 0 to 100. Higher numbers mean higher production potential.
• It rates the soil, not the farmer, the weather or the price of corn.
• Always look at the CPI of the tillable acres only, not the whole parcel.
• Minnesota's CPI is not the same scale as Iowa's CSR2, so don't compare an 85 to an 85.
• Use CPI to compare farms, then look at drainage, field shape, access and the lease before you decide what a farm is worth.

What does CPI actually measure?

The Crop Productivity Index comes from USDA Natural Resources Conservation Service (NRCS) soil survey data. It ranks Minnesota soils on their potential for intensive row-crop production, from 0 to 100. The rating looks at physical and chemical traits such as available water capacity, pH, slope, soil moisture, cation-exchange capacity, organic matter, salinity and surface fragments, and the traits chosen are the ones that matter for corn. (Minnesota Geospatial Commons, University of Minnesota Land Economics)

Two things it does not include: weather (rainfall and growing degree days) and management. The ratings assume adequate management, natural rainfall with no irrigation, and drainage where needed.

Why "tillable acres only" is the rule I use

A farm's soil map includes everything on the property: the field, but also the grove, the pasture corner, the waterway, the farmstead and the wet draw. Those acres can carry very different soils. If a number is averaged across the whole parcel, a few poor acres can pull a good field's score down, and the opposite can happen too.

That's why I look at the weighted average CPI of the tillable acres, and I show the tillable acres separately from total acres. Many Minnesota counties value cropland the same way: they use the parcel's weighted average CPI on its tillable acreage. Polk and Otter Tail counties have both published how they now use CPI for tillable land. (Polk County, Otter Tail County)

A recent local example: a 155.6-acre Winona County farm in Utica Township, with 153.86 tillable acres and a 92.1 CPI, brought a high bid of $15,200 per acre at an October 27, 2026 auction, before the 3% buyer's fee. (Tony Montgomery Realty & Auction) It was nearly all tillable and highly rated, which buyers like. The same score on a farm that's half woods and pasture would be a different conversation.

Is a higher CPI always worth more?

Usually a higher CPI is a point in a farm's favor, but it isn't the whole price. Two farms with the same CPI can sell very differently because of tile drainage, field size and shape, road access, the ratio of tillable to non-tillable ground, county, and what the market is doing that month. A soil rating measures potential, not fertility or actual yield, and lower-rated tracts sometimes outperform higher-rated ones. (Peoples Company)

Pro tip: Don't compare CPI to Iowa's CSR2 (Corn Suitability Rating). They're different scales built on different methods, so an 80 CSR2 in Iowa is not the same as an 80 CPI in Minnesota. The same source notes that even states that use a productivity index each make their own adjustments.

If you're selling farmland

• Pull the soils map and the weighted CPI for the tillable acres, and confirm the tillable acre count against your FSA records.
• Check that the acreage and soil map agree with the county's records. If your county uses CPI to value tillable land and you think your rating is wrong, counties like Polk and Otter Tail say you can appeal with an FSA soil map or a drawing of your tillable acres.
• Tell the full story: tile, field boundaries, access, any CRP or other enrollments. CPI is the starting point, not the pitch.

If you're buying farmland

• Ask for the CPI of the tillable acres and the number of tillable acres, not just the parcel average.
• Compare farms inside the same county first, then adjust for drainage and layout.
• Treat CPI as one tool alongside the soil map, recent nearby sales and the lease terms.

The bottom line

CPI is one of the cleanest ways to compare Minnesota soils side by side, and a good listing shows it the right way: weighted for the tillable acres, clearly labeled and backed by the soil map. Use it to ask better questions, then look at the whole farm.

Talk with me

Thinking about selling, buying or just finding out what your farm's soils look like on paper? I'd be glad to pull the soil map and talk it through, with no pressure. Call me at (507) 923-7657, request a free valuation on midwestfarmrealty.com, or browse our current farm and land listings.

Frequently Asked Questions About CPI

What does a 90 CPI mean?

It means the soil on that land ranks very high on the 0 to 100 Minnesota scale for row-crop production potential. It's a relative ranking against other Minnesota soils, not a predicted yield.

Is CPI the same as CSR2?

No. CSR2 is Iowa's rating and CPI is Minnesota's, and they use different methods. Don't compare them directly.

Where can I look up CPI for my land?

CPI is part of USDA NRCS soil data. Soil maps are available through the USDA Web Soil Survey, and many county assessor offices and Minnesota GIS tools show it. I'm also happy to pull it for you.

Does CPI set my farm's price or my property tax?

No. It's one input. Some counties use CPI on tillable acres in their assessments, along with local sales data, but your county assessor sets that value and can explain how it's applied.

Why do you list tillable acres separately?

Because tillable ground is what CPI is meant to rate, and it keeps woods, pasture, waterways and buildings from skewing the number.

About the author: Jennifer Busch is an Accredited Land Consultant (ALC) and broker with United Country Real Estate | Midwest Home & Farm Realty, serving Kasson, Rochester and southeast Minnesota.

Jennifer Busch, United Country Real Estate | Midwest Home & Farm Realty 1101 3rd St NE, Kasson MN 55944 | (507) 923-7657

This post is general information, not an appraisal, soil-science, tax or legal advice. Soil ratings and values vary by parcel, and past sales don't guarantee future results. Always confirm acreage, soils and assessments with the county and your own advisors.