Follow the simple three-step plan to create and analyze your own Minnesota soils' attributes database. You can also examine all variables if you click on Individual Records. When you're ready to go, click Generate Report. Or, to see your data in a map, click on our new feature: MLE Map on the left-side menu.

You’ll need to choose the geographic area you want covered, which data elements you want us to provide, and how you want us to display the data. You do this by first choosing your Boundaries (county, watershed…), then your Location (specific county and township/city), and finally your Attributes (year, summary level…).

Where appropriate, use Continue to move back to the main page and view your updated choices. To move back to the main page without making your changes take effect, press Cancel.

Soils data for crop and forest indices and potential erosion rates are drawn from the USDA Natural Resources Conservation Service. These data do not commonly change over time, but as  counties are completed by NRCS, the attribute records used herein will be updated.These files include attributes for every Minnesota soil mapped and classified by the NRCS. Some counties do not have soil surveys, so they have no associated data. The Minnesota Crop Productivity Index is currently available on the Web Soil Survey and on this site. Coverage will eventually include all Minnesota counties.

For details on the Web Soil Survey, click here.

Minnesota Crop Productivity Index (CPI)

The Minnesota Crop Productivity Index (CPI) ratings provide a relative ranking of soils based on their potential for intensive row crop production. An index can be used to rate the potential yield of one soil against that of another over a period of time. Ratings range from 0 to 100. The higher numbers indicate higher production potential.

The CPI ratings do not take into account climatic factors, such as the differences in precipitation or growing degree days across Minnesota. The ratings are based on physical and chemical properties of the soils and on such hazards as flooding or ponding. Available water capacity, reaction (pH), slope, soil moisture status, cation-exchange capacity (CEC), organic matter content, salinity, and surface fragments are the major properties evaluated when CPI ratings are generated. The soil properties selected are those that are important for the production of corn.

All soil component mapping phases in Minnesota were evaluated using the Cropland Productivity rule in the National Soil Information System (NASIS), and a CPI was generated for each phase. A statistical mean CPI value was created for each soil component mapping phase. All map units were populated with each component’s mean CPI value, and a weighted average CPI was created for each soil map unit in the state. An individual map unit (for example, Canisteo clay loam, 0 to 2 percent slopes) will have the same CPI value wherever that map unit occurs throughout the state.

When the soils are rated, the following assumptions are made: a) adequate management, b) no irrigation, c) artificial drainage where required, d) no land leveling or terracing, and e) no climatic factors considered.

The map unit CPI was used to update the map unit crop yields for corn and soybeans. Even though predicted average yields will change with time, the productivity indices are expected to remain relatively constant in relation to one another over time.

Minnesota Aspen Productivity Index (API), aka Forest Productivity Index (FPI)

The Minnesota Aspen Productivity Index (API) ratings provide a relative ranking of soils based on their potential for growth of quaking aspen (Populus tremuloides Michx.).  The index can be used to rate the potential yield of one soil compared to that of another over a period of time. Ratings range from 0 to 100. The higher numbers indicate higher potential for aspen growth.

The API ratings do not take into account climatic factors, such as the differences in precipitation or growing degree days across Minnesota. The ratings are based on physical and chemical properties of the soils and were aggregated into three categories: by their effects on water availability (including soil drainage class, depth to water table, and available water storage), on nutrient availability (including organic matter and exchangeable bases), and by other (site) factors (including bulk density of the rooting zone and stone content).

All soil component mapping phases in Minnesota were evaluated, and a API was generated for each phase. A statistical mean API value was created for each soil component mapping phase. All map units were populated with each component’s mean API value, and a weighted average API was created for each soil map unit in the state. An individual map unit (for example, Warba fine sandy loam, 1 to 8 percent slopes) will have the same API value wherever that map unit occurs throughout the state.

When the soils are rated, traditional aspen management, including clearcut harvest with natural regeneration, is assumed.  Tree growth is not only influenced by soil properties but by such variables as climate, stand history, and management.  In addition, soil properties are highly variable in forested landscapes, and the index only considers properties of the average soil.  Despite these qualifications, the indices for specific soils are expected to remain relatively constant in relation to one another over time.

Predicted erosion rates

The values shown here are potential erosion in tons/acre/year. The water erosion numbers are based on the RKLS factors of the Universal Soil Loss Equation (USLE) for water erosion, where R=rainfall factor, K=soil erodibility factor and LS=slope length gradient factor. The wind erosion numbers are based on the I and C factors the of the wind erosion function, where I=soil erodibility index and C=climate factor.

Soil management activities which reduce soil erosion such as crop residue, buffer strips, terraces, sod waterways and windbreaks were not included. Consequently, these numbers can be viewed as the maximum potential erosion. The actual rate of erosion will likely be lower due to soil management practices.  By applying one or more management practices, soil loss on many landscapes can be reduced to 5 tons or less per acre per year, the generally accepted maximum erosion rate—or “tolerable level” ---- that minimizes loss of soil productivity.  

Erosion is site-specific, and the rate of soil erosion may vary widely within a small area. Potential erosion rates provide a generalized landscape perspective of the risks posed by soil erosion unless soil management practices are implemented.  Areas with high potential soil erosion require more soil management practices to reduce soil erosion to tolerable levels.