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The National Resources Inventory (NRI) is a
statistically based survey that has been designed and
implemented using scientific principles to assess conditions and
trends of soil, water, and related resources on non-Federal
lands in the United States.
The NRI is conducted by the U.S.
Department of Agriculture's Natural Resources Conservation
Service in cooperation with the Iowa State University
Statistical Laboratory. It is a compilation of natural resource
information on non-Federal land--nearly 75 percent of the
Nation’s total land area.
The 1997 NRI captures data on land cover and use, soil
erosion, prime farmland soils, wetlands, habitat diversity,
selected conservation practices, and related resource attributes
at more than 800,000 scientifically selected sample sites.
Data used for the NRI were collected using a variety of
imagery, field office records, historical records and data,
ancillary materials, and a limited number of on-site visits. The
data have been compiled, verified, and analyzed to provide a
comprehensive look at the state of the Nation's non-Federal
lands.
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In 1997, forest land was the dominate land use (44.6 percent), followed by
pastureland (18.5 percent), cropland (17.2 percent), and developed
land (8.8 percent) . Federal land totaled about 1.2 million acres (4.6
percent) in 1997 while all non-federal land amounted to just over 24.9
million acres (view
this data as a pie chart).
Land use is not static, however. It is surprisingly dynamic, with annual shifts in and out of different uses. In agriculture there are constant shifts in the use of land among cropland, pasture, and forest land to meet production needs, implement rotations of land in and out of cultivation, and maintain and sustain soil resources.
Between 1982 and 1997, cropland and land enrolled in the Conservation Reserve Program (CRP) declined
573 thousand acres, pastureland 333 thousand acres, and forest land 35
thousand acres. The largest increase in acreage by land use was for development, about
866 thousand acres, from 6 percent of the nonfederal land area in 1982 to 9.5 percent in 1997.
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Sheet and rill erosion is the removal of layers of soil from the land surface by the action of
rainfall and runoff. It is the first stage in water erosion. It does not include gully or stream bank erosion.
Total sheet and rill erosion on cropland and Conservation Reserve Program (CRP) land has decreased from 52.7 million tons per year in 1982 to 26.1 million tons per year in 1997, a reduction of slightly over 50 percent in the 15 year period. Stewardship by agricultural producers and private landowners on Tennessee's lands hit an all-time high with successful implementation of the 1985 and 1990 Farm Bills
(view as a bar chart).
Cropland erosion rates have fallen from 9.4 tons per acre per year in 1982 to
5.6 tons per acre per year in 1997, a decrease of 40 percent. Since 1992,
erosion rates have fallen from 7.1 tons per acre per year to a 1997 level of 5.6
tons per acre per year, a decrease of 1.5 tons per acre per year or 21 percent (view
as a bar chart).
Pastureland erosion rates have remained steady from 1982 to 1997 at less than 1 ton/acre/year.
Excessive soil erosion continues to be a serious problem in many parts of the state. In 1997, more than 2 million acres of fragile highly erodible cropland produced an estimated 18.8 million tons of erosion. The 2.6 million acres of non-highly erodible cropland in Tennessee produced an estimated 7.1 million tons of erosion during the same time period to bring the total soil loss to 25.8 million tons per year for all cropland in Tennessee.
Of the 4.6 million acres of cropland in Tennessee, 3 million acres (65%) are eroding at or below the soil loss tolerance, while 1.6 million acres (35%) are eroding at a rate that exceeds the soil loss tolerance
(view as a pie chart).
Excessive erosion rates indicate areas where erosion control measures can improve soil quality, sequester carbon, and reach goals to reduce greenhouse gases in the atmosphere.
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Land development and urbanization leads to fragmentation of agricultural and forest land; loss of prime farmland, wildlife habitat, and other resources; and competition for water.
In 1992, developed land totaled a little over 1.9 million acres, about 7.9% of Tennessee's non-federal land area. However, in the 5-year period between 1992 and 1997, the pace of development (about
80,000 acres a year) was more that 1.7 times that of the previous 10-year period, 1982-92 (46,000 acres a year). Over the 15-year period, 1982-97, the total acreage of developed land increased by more than 865,000
acres, a 63.5 percent increase. Tennessee ranks 7th in the nation of total acres
of land developed 1992 to 1997 (see
Developed Land "Top Ten" States) (see State Ranking by Acreage and Rate of Non-Federal Land Developed).
Non-Federal forest land is the dominant land type being developed. Of the
401,900 acres of land developed between 1992-97, 175,500 acres were forest land, 124,700 acres were pastureland, and 85,700 were cropland.
Between 1992 and 1997, more than 124,000 acres of prime farmland were
converted to developed land, on average more than 24,000 acres of prime farmland
per year overall. During this time period, the amount of prime farmland being
converted to developed land was about 68 acres a day (see
Acres and Percent of Developed Land 1992-1997 that was Prime Farmland in 1992, and Average Annual Rate of Development 1992-1997).
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