About the National Resources Inventory

The National Resources Inventory (NRI) is a statistical survey of land use and natural resource conditions and trends on U.S. non-Federal lands.  Non-Federal land includes privately owned land, tribal and trust land, and lands controlled by State and local governments. The NRI is conducted by the Natural Resources Conservation Service in cooperation with Iowa State University's Center for Survey Statistics and Methodology.

The NRI program serves as the Federal Government's principal source of information on the status, condition, and trends of soil, water, and related resources in the United States. The assessment of the nation's natural resources and environmental condition provided by the NRI requires a nationally consistent database that allows for manipulation of various parameters in order to make accurate assessments. For these manipulations and subsequent analyses to be useful for public policy considerations, the NRI database has these characteristics:

• Has a high degree of reliability
• Looks at the natural resources over a period of time
• Permits analyses at national, regional, and local levels

The NRI is unique because it:

• Features data gathered and monitored since 1982 by thousands of technical and natural resource data collection experts
• Is directly linked to the NRCS Soil Survey database which permits analysis of resources in relation to soil resources and conditions
• Provides a nationally consistent database that can be used to statistically evaluate trends in natural resources over time for all non-Federal lands

The NRI plays a key role in development of conservation policy and programs for the Nation.  It serves to educate the public regarding natural resource issues and provides a comprehensive nationally consistent source of data for researchers in many fields.  Informed and valid decisions are best made when based upon scientifically derived data. The NRI has been developed to supply this type of information. The NRI database is powerful, credible, and scientifically constructed. The present NRI is the result of many decades of development.

NRI sampling units have been established across all parts of the Nation using a stratified two-stage, unequal probability area sampling scheme. The first-stage sampling unit, or primary sampling unit (PSU), is an area/segment of land; the second-stage sampling units are points located within the PSUs. The national "foundation" or framework sample consists of about 300,000 PSUs and 800,000 sample points. Data are collected for both the first- and second-stage sampling units using remote sensing (photo interpretation) supported by onsite field investigation.

The NRI was conducted every 5 years during the period 1977 through 1997, but currently is in transition to a continuous, or annual, inventory process.  This shift helps align the NRI with the need for timely information to support development and assessment of agricultural and conservation policies and programs.  A continuous inventory approach also distributes the NRI workload more evenly across years and provides efficiencies in the data gathering and quality assurance processes.

The 2002 Annual NRI is the second of the annual NRI releases and presents national-level estimates for Land Use and national and regional-level estimates for Wetlands status and trends on non-Federal lands.  Subsequent Annual NRIs will provide a broader spectrum of results -- additional topics, and estimates at additional geographic levels (State-level and eventually sub-State).

Last Updated 4/22/2004

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