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Net Change in Acreage of Prime Farmland used as Pastureland, 1992 - 1997
Description
This dot density map shows the general
distribution of areas where there were net gains
or losses in acreage of prime farmland used as
pastureland from 1992 to 1997 within each 8-
digit hydrologic unit. Each red dot represents
a net loss of 2,000 acres of prime farmland used
as cropland. This loss may be due either to
loss of prime farmland or to conversion of prime
farmland to a non-pastureland land use. Each
green dot represents a net gain of 2,000 acres
of prime farmland used as pastureland. This gain
may be either new prime farmland or prime
farmland that was previously not used as
pastureland. Dots were aggregated by and placed
randomly within 8-digit hydrologic units. Areas
with 95% or more Federal area are shaded gray.
There was a total increase of 2,054,500 acres, a
total decrease of 3,312,400 acres. The net
increase for the U.S. was 1,257,900 acres.
Cautions for this Product:
Note that either a change in the amount of prime
farmland or a change in how prime farmland is
used will change the amount of prime farmland
that is used as pastureland. This map does not
show the source of change. This map may not be
used to determine site-specific information.
Within an 8-digit hydrologic unit, dot counts
represent acreage totals correctly plus or minus
one dot to account for remainders. Data are not
collected on Federal land. Data are not
available for Alaska or the Pacific Basin. Data
for Puerto Rico and the U.S. Virgin Islands are
aggregated by 6-digit hydrologic unit.
Sources
Source:
National Resources Inventory, 1997
Distributor:
USDA-NRCS-RIAD
Reliability:
NRI sample data are generally reliable at the
95% confidence interval for state and certain
broad substate area analyses. Generally,
analyses that aggregate data points by smaller
geographic areas and/or more specific criteria
result in fewer data points for each aggregation
and therefore less reliable estimates. NRI maps
reflect national patterns rather than site-
specific information.
Layers
Aggregate Layer:
Cross of State with 8 Digit Hydrologic Units and
Federal Land
Other Layers Displayed:
States, Rivers
Definitions
Federal land:
A land ownership class designating land that is
owned by the Federal Government. It does not
include, for example, trust lands administered
by the Bureau of Indian Affairs nor Tennessee
Valley Authority (TVA) land. No data are
collected for any year that land is in this
ownership. [NRI-97]
Hydrologic units:
A hierarchical system developed by the U.S.
Geological Survey that divides the United States
and the Caribbean into 21 major regions, 222
subregions, 352 accounting units, and further
subdivided into 2,150 cataloging units that
delineate river basins having drainage areas
usually greater than 700 square miles. [USGS]
Pastureland and Native Pasture:
A Land Cover/Use category of land managed
primarily for the production of introduced or
native forage plants for livestock grazing.
Pastureland may consist of a single species in a
pure stand, a grass mixture or a grass-legume
mixture. Management usually consists of
cultural treatments-fertilization, weed control,
reseeding, or renovation and control of
grazing. (For the NRI, includes land that has a
vegetative cover of grasses, legumes, and/or
forbs, regardless of whether or not it is being
grazed by livestock.) [NRI-97]
Prime farmland:
Land that has the best combination of physical
and chemical characteristics for producing food,
feed, forage, fiber, and oilseed crops and is
also available for these uses. It has the soil
quality, growing season, and moisture supply
needed to produce economically sustained high
yields of crops when treated and managed
according to acceptable farming methods,
including water management. In general, prime
farmlands have an adequate and dependable water
supply from precipitation or irrigation, a
favorable temperature and growing season,
acceptable acidity or alkalinity, acceptable
salt and sodium content, and few or no rocks.
They are permeable to water and air. Prime
farmlands are not excessively erodible or
saturated with water for a long period of time,
and they either do not flood frequently or are
protected from flooding.[SSM, USDA Handbook No.
18, October 1993]
Product Information
Product ID:
5564
Production Date:
3/21/00
Product Type:
Map
For additional information
contact the Resources Inventory and Assessment Division.
Please include the Product ID you are inquiring about.
nri@wdc.usda.gov
or 1400 Independence Avenue SW - P.O. Box 2890 -
Washington D.C. 20013. If you use our analysis products,
please be aware of our disclaimer.
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