Introduction to Missouri NRI
The summary results presented in the Missouri NRI tables are derived from the 2007 NRI. The 2007 NRI is the latest in a series of natural resource inventories conducted by the U.S. Department of Agriculture's Natural Resources Conservation Service (NRCS). The NRI is a scientifically based, longitudinal panel survey of the Nation's soil, water and related resources, designed to assess conditions and trends on non-Federal lands. Non-Federal lands include privately owned lands, tribal and trust lands, and land controlled by State and local governments. The NRI was conducted on a five-year cycle from1977 to 1997, but is now collected annually. In Missouri, the five-year cycle collected data from 8,700 sites; Missouri's annual data collection occurs for 2,200 sample sites. The 2007 NRI provides nationally consistent data for the 25-year period 1982-2007; constructed specifically to estimate 5-, 10-, 15-, 20- and 25-year trends for six points in time: 1982, 1987, 1992, 1997, 2002 and 2007. The 2007 NRI statistically updated the 1997 NRI results. Only the 2007 NRI database should be used to compare 2007 conditions with those of earlier years. Comparisons using NRI data published prior to 2007 can produce incorrect inferences. The 1977 NRI estimates are not used in the NRI trending databases. The 1977 NRI was designed for State-level statistical reliability. The 1982 and following NRI inventories expanded their scope and sample sizes were expanded to meet multi-county level statistical reliability measures.
Sample sites utilized by the NRI inventories were formerly called Primary Sample Units (PSUs) and are now referred to as segments. In Missouri, the typical segment is a 160 acre tract. Within each segment, data are collected for up to three points. There are 26,000 permanent segment point locations in Missouri. The 1982 data collection involved on-site visits to each segment point and reviews of field office records. Data collection for 1987, 1992 and 1997 relied on USDA's Farm Services Agency 35mm color compliance aerial slides and field office records. Revised standards and protocols were developed nationally by NRCS in collaboration with the Statistical Laboratory at Iowa State University and implemented for the 1997 NRI. Oversight and management of data-gathering were assigned to 21 regional units nationwide. These units, called Inventory Collection and Coordination Sites (ICCSs) were established according to regional land use patterns and state allocations of resources. The ICCS in Ames, Iowa oversaw data collection for Iowa and Missouri from 1997 to 2003. From 2004 onward, Missouri data collection has been managed from the NRCS Central Remote Sensing Laboratory (CRSL) located in Ft. Worth, Texas.
In 1998, NRCS initiated a five year transition to the annual inventory process. The first annual data collection was done in 2000 and continued through 2003. NRCS policy has been modified to ensure that the annual process is science based and that quality assurance protocols are implemented and monitored at national, regional and local levels. The Annual NRI inventory is part of an evolving resource inventory methodology that includes developing a multi-agency integrated inventory approach, incorporation of a wider variety of tools for assessment of resource health and further development of analysis capabilities to support policy analysis and program implementation. The five year transition period, ending with data collection during the summer of 2003, involved small, annual special inventories based on field office records, FSA compliance aerial photography and NRCS large scale, color aerial photography.
NRI data release procedures have been impacted by the implementation of annual data collection because the scale of NRI estimates is affected by the reduced sample sizes. Estimates for a particular level of geography are only released when they meet NRI statistical standards and are scientifically credible in accordance with NRCS policy and Office of Management and Budget (OMB) and United States Department of Agriculture (USDA) Quality of Information Guidelines.
The 2007 NRI data are suitable for national, regional and state level analyses. All available state level estimates are reported here. These state level results will be supplemented with additional estimates on soil erosion and land use as they become available. Updated sub-state level data, comparable to the 1997 NRI data, are much in demand and efforts are underway to develop the statistical protocols for constructing sub-state level estimates for the Annual NRI process.
Missouri's Annual NRI features a yearly inventory of approximately 2,200 segments. Each sample unit requires the collection of supporting field office information and photo interpretation as part of the data collection process. All field office and on-site data gathering is coordinated through Missouri's NRCS Area Resource Soil Scientists and the State Resource Inventory Coordinator.
The annual sample is divided into two major types of segments:
1. Core Sample - About 1,200 segments have been observed annually from 2000 and used for short-term trend determination.
2. Rotation Sample - About 1,000 segments from the pool of non-core segments that are rotated through the annual inventory sample.
The Missouri NRI is currently using scanned 9x9 color aerial photography with a contact scale of 1:7,920 (1 inch = 666 ft.) for photo interpretation-based data collection. This high quality analog source photography has a ground sample distance of less than 1 foot. The USDA Farm Services Agency's Aerial Photography Field Office (APFO) provides contract administration and film inspection services for all the NRI photography acquired nationwide.
2007 NRI data are available on the NRI website at the national NRI Web site. About 1,200 segments have been observed annually from 2000 and used for short-term trend determination.