The National Resources Inventory (NRI) is a scientifically-designed, longitudinal panel survey of the Nation's soil, water, and related resources designed to assess conditions and trends every five years. The NRI is conducted by the Natural Resources Conservation Service (NRCS), an agency of the U.S. Department of Agriculture (USDA), in cooperation with the Iowa State University (ISU) Statistical Laboratory. The 1997 NRI contains data on nonfederal lands and water areas within the 48 conterminous United States, Hawaii, Puerto Rico, and the U.S. Virgin Islands. The 1997 NRI provides results that are nationally consistent for all nonfederal lands for four points in time - 1982, 1987, 1992, and 1997.

This data set follows similiarly to the 1997 (revised December 2000) National Resources Inventory data set produced by the U.S. Department of Agriculture, Natural Resources Conservation Service. It does not contain all the attribute data tables in the original source NRI tabular data base issued by the NRCS. Rather, it is a portion thereof, consisting only of those tables most useful for performing pesticide risk assesments. To obtain the entire original source NRI tabular or spatial data sets, visit the following web site: http://www.nrcs.usda.gov/technical/NRI/.

The NRI database is a statistical database. The data do not come in a summarized or aggregated form. Users of the database decide which portions of the data are needed, and how to aggregate and summarize the data most effectively. The data must be aggregated to develop meaningful statistics and analyses. To use the individual sample point data as other than a part of the statistical database is inappropriate; for example, it is a misuse to use the NRI database to attempt to identify a specific farm and field where certain conservation actions should be initiated. Tabulations made from the NRI database are estimates. These tabulations produce estimates rather than facts because they are based upon sample data derived from a survey - rather than data coming from a census, or complete measurement. Each estimate has some degree of statistical uncertainty associated with it; this statistical uncertainty affects analyses of the data and interpretation of results. All data summaries and analyses must take into account the database weights (expansion factors) and at least some type of geographical factors.

Less than 1% of the point table recordid values did not match a spatial representation of its FIPS/MLRA/HUC, but some blanks do exist. Likewise, some spatial NRI polygons exist that do not have tabular information. This discrepancy may be explained by different spatial data sets used by NRCS and GeoStac, as well as by actual changes in counties or MLRA codes and boundaries.

Extracted the original source 1997 NRI tabular data sets produced by the USDA NRCS, and compiled those tables of interest for use with pesticide risk assesment, including: Point, Trend, WEQ, Wetland, and Crophist tables in a Microsoft Access database.

Entity_and_Attribute_Overview:

This NRI tabular data base consists of the following tables:

1) Point: Data that are not year-specific. This table serves as the "master table" relative to the relational structure. This master table includes two required variables for any data summary: the sample point weights or expansion factors (xfact) and a geographical factor (fips, hydro, or mlra). Almost all data tabulations and analyses will require data from this master table and one or more of the other tables, often the table trend.

2) Trend: Trending data that are year-specific and are available for at least two inventory years (usually for all four inventory years: 1982, 1987, 1992, 1997). Refer to the Point Record Layout and Database Design "Field Name" column to see what years are available for a particular variable.

3) WEQ: Wind erosion equation factors for each inventory year plus the three prior calendar years (only for those points that have Broad Cover/Uses of Cropland, Pastureland, or CRP in a given inventory year). The Average Annual Wind Erosion Equation (aaweq) is included in table trend. "aaweq" is the estimated soil loss due to wind erosion averaged for the rotation during the four-year period.

4) Wetland: The Cowardin classification system covers both wetlands and aquatic deepwater habitats. Wetland and deepwater habitat determinations are included in the 1997 NRI database for all nonfederal points for inventory year 1997 only. FSA wetland classifications are also included. Use the Cowardin System data element to replicate estimates found in Table 16 of the 1997 NRI Summary Report. The Cowardin Specific data element provides a more specific Cowardin system category.

5) Crophist: Data on cropping history for the three calendar years prior to the inventory years (only for those points that have Broad Cover/Uses of Cropland, Pastureland, or CRP in a given inventory year).

This metadata document does not define each of the possible field types or the data variables for the three mentioned tables. To learn more about the field types or possible data variables, users should refer to the original source publication, "A GUIDE FOR USERS OF 1997 NRI DATA FILES," published in 1997 (revised December 2000) by the US Department of Agriculture, Natural Resources Conservation Service. This publication has been included as a suppliment for use with this NRI data base and should be delivered with the data base throughout it's life. In addition Look Up Tables are included with the database.

U.S. Department of Agriculture. 2000. Summary Report: 1997 National Resources Inventory (revised December 2000), Natural Resources Conservation Service, Washington, DC, and Statistical Laboratory, Iowa State University, Ames, Iowa, 89 pages. http://www.nrcs.usda.gov/technical/NRI/

NRI Tabular Data

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