How to Use the AUM Estimator
Note: Output will be in Animal Unit Months (AUMs) for the entire parcel being estimated.
Question: Is a soil survey available for the parcel to be calculated?
If NO, and the estimate is to be used for Montana Department of Revenue purposes, contact your county agricultural extension agent for an AUM estimate. If NO, and the estimate is to be used for conservation planning, the local Natural Resources Conservation Service office will provide the estimate using ecological site descriptions.
Note: The following documents should be saved to your computer and opened with Microsoft Word or Adobe Reader before filling in the worksheet.
If you encounter any problems with the file provided on this page, please contact Technical Resources at 406-587-6822.
View or download the AUM Estimator Worksheet in either of
the following formats. The following documents require either
Word or Adobe Reader.
Step 1. Using existing soil survey information, determine the soil map units that occur in the parcel. For sources of soil survey information, see Soil Maps.
Step 2. Estimate the acres of each soil map unit; then enter the Map Unit Symbol into column A and the Acres of this Map Unit in the Parcel into column B of the AUM Estimator Worksheet available above. The value in column B could be based on GIS calculations (ArcView calculations), dot counting with an acreage grid, or simply visually estimating the proportion of the different map units that occur in the parcel being estimated.
Step 3. Using the figures under the Range AUM (shortened for AUM/Acre) Column (use the below normal column for Montana Department of Revenue calculations or the appropriate column based on the predominant plant community for other uses) based on the Soil Survey Area Estimated AUM (shortened for AUM/Acre) Table for the survey area(s), populate Column C of the AUM Estimator Worksheet. Calculate Column D (Map Unit AUMs in this Parcel) using the directions as noted (see the Example Worksheet after Step 4. below). The Soil Survey Area Estimated AUM Table can be accessed via the web at: http://www.mt.nrcs.usda.gov/technical/ecs/range/aum.
Directions for Columns in the AUM Estimator Worksheet:
Step 4. Add the values in column D to obtain the Total Estimated Parcel AUMs. Use the Total Estimated Parcel AUMs in your specific application. In the case of the example below, the number would be 13.22 AUMs for the entire 32.7 acre parcel.