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National Resources Inventory 2001 Annual NRI
Urbanization and Development of Rural Land
The National Resources Inventory (NRI) is a statistical survey of natural
resource conditions and trends on nonfederal land in the United States -
nonfederal land includes privately owned lands, tribal and trust lands, and lands controlled by State and
local governments. The NRI provides nationally consistent statistical data on
how these lands are used and on changes in land use patterns for the period 1982
– 2001. Of particular interest is the conversion of various rural lands into
developed land. The NRI provides information on the types and quality of land
being developed, and can be used to help assess the effects of these
conversions.
Key Findings
- Between 1982 and 2001, about 34 million acres
- an area the size of Illinois - were converted to developed uses. By 2001,
the total developed area in the contiguous United States was slightly more
than 106 million acres.
- The rate of development between 1997 and
2001 averaged 2.2 million acres per year. This was the same average rate
experienced between 1992 and 1997, but up from 1.4 million
acres per year in the previous decade (1982 - 1992).
- Between 1997 and 2001, almost 9 million acres were developed, of which 46
percent came from forest land, 20
percent from cropland, and 16 percent from pastureland.
- Between 1997 and 2001, the rate of forest land and rangeland conversion to
developed uses continued on an upward trend.
- The rate of cropland conversion between 1997 and 2001 declined by 21
percent relative to the previous 5-year period (1992 - 1997).
- In the period between 1992 and 2001, about 6 million acres (28 percent) of
the new land developed was prime farmland. Between 1982 and 1992, about 4 million acres
(29 percent) of the new land developed, was prime
farmland.
- Correspondingly, the rate of prime farmland development increased from an average of 0.4
million acres per year between 1982 and 1992 to 0.6 million acres per year between 1992
and 2001. (see Land Use for more information on prime
farmland).
- While cropland remains the major type of prime farmland being developed,
its share of total prime farmland developed has declined. Between 1992 and 2001,
48 percent of the prime farmland developed was cropland, down from 57 percent in
the period between 1982 and 1992.
Importance to the Nation
The impact of development on rural nonfederal land is a concern in the
balancing of development needs with conservation of natural resources. This is
an especially important consideration when the lands best suited to producing
food and fiber come under development.
Conversion of agricultural land to
developed uses can also result in fragmentation of landscapes, leading to
diminished values for wildlife, water management, open space, and aesthetic
purposes, among others.
More Information
For more information about the NRI, visit
http://www.nrcs.usda.gov/technical/NRI/
See the 2001 NRI Glossary for definitions of key terms.
To obtain State and local 1997 NRI data, contact your NRI
coordinator. Links to State NRI websites and contact information can be found at:
http://www.nrcs.usda.gov/technical/NRI/1997/obtain_data.html
Send comments and questions to nri@nhq.nrcs.usda.gov
Developed Land by Type and Year
in Millions of Acres, with Margins of Error
Year |
Large Urban and Built-Up Areas |
Small Built-Up Areas |
Rural Transportation Land |
Total Developed Land |
1982 |
46.9 ± 0.7 |
4.7 ± 0.1 |
21.2 ± 0.2 |
72.8 ± 0.7 |
1987 |
52.6 ± 0.8 |
5.1 ± 0.1 |
21.3 ± 0.2 |
79.0 ± 0.8 |
1992 |
59.6 ± 0.8 |
5.4 ± 0.1 |
21.5 ± 0.2 |
86.5 ± 0.8 |
1997 |
69.8 ± 0.9 |
6.1 ± 0.1 |
21.6 ± 0.2 |
97.5 ± 0.9 |
2001 |
77.6 ± 1.1 |
6.7 ± 0.1 |
22.0 ± 0.2 |
106.3 ± 1.1 |
Sources of Newly Developed Land
in Thousands of Acres, with Margins of Error
Year |
Cropland |
Pastureland |
Rangeland |
Forest Land |
All Other
Land Uses |
Total |
1982 to 1992 (10 years) |
3,900 ± 160 |
2,270 ± 120 |
1,950 ± 190 |
5,600 ± 170 |
360 ± 50 |
14,080 ± 330 |
1992 to 1997 (5 years) |
2,880 ± 110 |
1,930 ± 100 |
1,270 ± 130 |
4,740 ± 140 |
470 ± 50 |
11,290 ± 250 |
1997 to 2001 (4 years) |
1,830 ± 170 |
1,470 ± 170 |
1,210 ± 290 |
4,150 ± 340 |
280 ± 70 |
8,940 ± 550 |
Prime Farmland by Land Use and Year
in Millions of Acres, with Margins of Error
Year |
Cropland |
Pastureland |
Forest Land |
All Other
Land Uses |
Total |
1982 |
231.5 ± 3.4 |
37.7 ± 1.4 |
46.9 ± 1.7 |
26.0 ± 1.3 |
342.1 ± 4.0 |
1987 |
226.8 ± 3.4 |
37.1 ± 1.4 |
47.2 ± 1.7 |
28.7 ± 1.3 |
339.8 ± 4.0 |
1992 |
217.0 ± 3.3 |
37.2 ± 1.4 |
47.6 ± 1.7 |
34.7 ± 1.3 |
336.5 ± 4.0 |
1997 |
213.5 ± 3.3 |
35.4 ± 1.4 |
48.8 ± 1.7 |
34.9 ± 1.3 |
332.6 ± 4.0 |
2001 |
209.4 ± 3.3 |
35.1 ± 1.4 |
50.0 ± 1.7 |
35.1 ± 1.3 |
329.6 ± 4.0 |
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About the Data
Estimates presented here are based upon the latest information from the National Resources Inventory (NRI). The NRI is a longitudinal sample survey based upon scientific statistical principles and procedures. It is conducted by the U.S. Department of Agriculture’s Natural Resources Conservation Service (NRCS), in cooperation with Iowa State University’s Center for Survey Statistics and Methodology.
The results are the first available from the new Annual NRI. Previously, NRI data were collected at 800,000 sample sites every 5 years.
Now the data are collected every year, but for slightly less than 25 percent of these same sample sites. The 2001 data are suitable only for analysis at a national scale because of this reduced sample size. As additional data are collected each year, results will become available for regional, state, and sub-state analysis. Current estimates cover the contiguous 48 states. Future estimates will also cover Hawaii, Alaska, the Caribbean, and selected Pacific Basin islands.
The findings on Urbanization and Development come from the NRI data
category “Land Cover/Use” which comprises mutually exclusive categories such as
cropland, pastureland, rangeland, forest land, other rural land, developed land,
and water areas. The NRI uses this classification to account for each and every
acre of nonfederal land within the Nation. Every parcel of land is described by
one and only one of these categories.
Developed Land contains three Land Cover/use
categories:
-
Large Urban & Built-up Areas (greater than 10 acres in size);
-
Small built-up Areas (less than 10 acres in size);
-
Rural Transportation Land (roads, railroads, and associated
rights-of-way).
For the NRI, Developed Land areas are considered
(permanently) removed from the rural land base. Other agencies and groups that
collect seemingly similar data have different reasons for collecting data. This
means that these other sources of data will show differences and similarities
with NRI data. Thorough examination and analysis of the data from two differing
sources can be beneficial and strengthen understanding of the issues.
The NRI approach to conducting inventories facilitates
examining trends in rural and developed land uses over time because –
- the same data have been collected since 1982 [definitions and protocols have remained the same],
- the inventory accounts for 100 percent of the surface area,
- quality assurance and statistical procedures are designed to ensure that trend data are scientifically legitimate and unambiguous, and
- it is easy to track lands as they go from one land-use category to another.
Irrespective of the scale of analysis, margins of error must be considered. Margins of error are presented for all
NRI estimates.
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Sources of Newly Developed Land that was Prime Farmland
in Thousands of Acres, with Margins of Error
Year |
Cropland |
Pastureland |
Forest Land |
All Other
Land Uses |
Total |
1982 to 1992 (10 years) |
2,290 ± 130 |
700 ± 60 |
840 ± 70 |
180 ± 30 |
4,010 ± 160 |
1992 to 1997 (5 years) |
1,670 ± 90 |
630 ± 60 |
700 ± 50 |
210 ± 30 |
3,210 ± 120 |
1997 to 2001 (4 years) |
1,030 ± 120 |
500 ± 80 |
640 ± 90 |
190 ± 60 |
2,360 ± 180 |
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