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Department of Revenue Use of Soil Survey Fact Sheet

Department of Revenue Use of Soil Survey for Agricultural Land Evaluation Fact Sheet

The Montana Department of Revenue (DOR) has been working closely with the Natural Resources Conservation Service (NRCS) for several years to effectively incorporate soil survey information into the upcoming reappraisal of agricultural land in Montana. A statewide reappraisal has not been done for many decades.

The near completeness of Montana’s soil inventory and the use in Montana of a statewide crop yield model for small grains greatly facilitated consideration of using soils data as a foundation for this mandated DOR reappraisal.

The DOR agricultural land reappraisal is in the final stages, with maps and DOR-generated productivity values recently being mailed to producers/landowners. The productivity values they will be receiving are for irrigated crops (alfalfa hay based), dry land crops (spring wheat based), animal unit month (AUM) data for grazing lands (component range production based), and forestlands (University of Montana Model used). The productivity values are based on map unit weighted averages, considering all contributing soil components.

It is very important to note that yield data used from the NRCS certified soils data is not used verbatim but is significantly post-modified in the process of estimating productivity for land evaluation. One reason for this is to obtain regional pertinence and balance in the context of countywide yield averages as well as the use of proxy values where the certified soils data is lacking (primarily irrigated yields and areas of Denied Access). As a result, the productivity values on the DOR-provided production maps will not match the NRCS certified soils yield data. They may be lower or higher depending on several variables in DOR’s process.

The agreement and associated process established between the NRCS State Soil Scientist and the DOR for addressing landowner queries as to productivity is as follows: The county assessor will gather information provided by landowners relative to yields being low (not likely an issue) or high for a particular agricultural land use (irrigated cropland, dry cropland, or grazing). This information is entered into DOR’s computer system and aggregated for analysis at the county level and broader. Based on how widespread or local the identified productivity anomalies end up being, after viewing all issues in a broad geographic context, the DOR has the option of tweaking their post-processing of the NRCS data or providing NRCS Soils Staff a list of map units for NRCS to investigate.

NRCS Resource Soil Scientists or Field Office Staff who are approached with DOR-provided soil productivity issues relative to their reappraisal process are to refer them to the appropriate DOR county assessor. This will ensure that the productivity issues work their way properly through the system, and any needed adjustments are made appropriately, whether to the DOR application of the NRCS Certified Soil Data or investigated on a map unit basis by NRCS Soils Staff.

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This fact sheet is also available in Acrobat Reader format.

Department of Revenue Use of Soil Survey for Agricultural Land Evaluation (PDF; 57 KB)