NRI Database Characteristics 

Data collected in the 1997 NRI provide a basis for analysis of 5-, 10-, and 15-year trends in resource conditions.  Many data items in the 1997 NRI are consistent with previous inventories.  In addition, the NRI is linked to NRCS's extensive Soil Interpretations Records database to provide additional soils information.  Data from other sources can be integrated with the NRI through spatial linkages in a Geographic Information System.

Data elements consistent within the NRI database among the last four (1982, 1987, 1992 and 1997) NRI's (links are to glossary definitions):

• Area in farmsteads & ranch headquarters
• Small built-up areas
• Large urban and built-up
• Small stream length and width
• Small waterbody types and size
• Land cover/use
• Cropping history
• Irrigation type and source of water
• Erosion data-wind and water
• Wetlands (1987 not available)

New data elements added for the 1992 NRI and continued in 1997:

• Rural transportation facilities
• Large stream area
• Large waterbody types and size
• Conservation Reserve Program (CRP)
• Irrigation water delivery system
• Food Security Act (FSA) wetland classification

Data elements added for the 1997 NRI:

• Shoreline characterization
• Conservation Reserve program (CRP) practice type and acreage
• Wildlife habitat composition and configuration
• Overland flow/delivery to water
• Wetland/Deepwater Habitat
• Reason for wetland gain/loss
• Wetland size
• USDA wetland program participation
• Conservation practices
• Saline deposits on agricultural land

Sample Design

NRI data is collected at scientifically designed sample sites located in every county and parish throughout the United States.  The sample design is the result of more than 40 years of research and application.

It is important to distinguish the NRI as a sample as opposed to a census.  Samples for the NRI are selected using a two-stage stratified area sample scheme (See figure at right).  The first-stage sampling unit, or primary sampling unit (PSU) is an area or segment of land.  The second-stage sampling units are points located within the PSUs.  See PSU image to the right.

Although sampling rates vary across strata, the sampling units constitute about 3 percent of all the total land and water areas of the 48 conterminous States, Hawaii, Puerto Rico, and the U.S. Virgin Islands.  

This image illustrates a Primary Sampling Unit (PSU), which are 100 acres in size in New Hampshire,  with three data points within this PSU.

Link to National NRI website on Statistical Design for scientific citations. 

Data Collection

Data for the 1997 NRI was collected predominately using remote sensing techniques.   To find out more about the data collection methods, visit the National NRI Website on Data Collection Methods.

Types of Data Reports

• Area reports on acreage within a specified area that does or does not meet the user defined condition, practice, or use.
• Non area reports about year specific units of measure other than acreage that meet user defined condition, practice, or use. 
• Trending analyses 5-year, 10-year and 15-year time spans for some data elements in the 1997 NRI. 
• Changes reports on the shift from one use, condition, or practice to another.

Getting NRI Data

Find out how to get NRI Data