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Percent Change in Cropland Area, 1982 - 1997

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Description

This shaded polygon map shows the percent change in the amount of cropland (cultivated and non- cultivated) area from 1982 to 1997 within each 8 digit hydrologic unit, using 1982 as a base year. The percentages are presented in five categories based on the following divisions: an increase of more than 25%, an increase of 5% to 25%, little change (less than 5% change), a decrease of 5% to 25%, and a decrease of over 25%. Areas with less than 5% cropland in either 1982 or 1992 are hatched. Areas with 95% or more Federal area are shaded gray.

Cautions for this Product:
Areas with small amounts of cropland may have very high rates of change. This map is best used in conjunction with a map showing percent area in cropland.



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: 8 Digit Hydrologic Unit Areas with Federal Land
Other Layers Displayed: Rivers, States


Definitions

Cropland:
A Land cover/use category that includes areas used for the production of adapted crops for harvest. Two subcategories of cropland are recognized: cultivated and noncultivated. Cultivated cropland comprises land in row crops or close-grown crops and also other cultivated cropland, for example, hayland or pastureland that is in a rotation with row or close-grown crops. Noncultivated cropland includes permanent hayland and horticultural cropland. [NRI-97]

Cultivated Cropland:
Includes land identified as being in row or close crops, summer fallow, aquaculture in crop rotation or other cropland not planted -- including cropland in short-term set-aside programs; or land in horticulture that is double cropped; or land in hay which had at least one of the three previous years in row or close grown crops; or land in pasture which had at least one of the three previous years in row or close grown crops.

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]

Non-cultivated cropland:
Includes land in horticulture that is not double- cropped; or land in hay which had not been in row or close-grown crops for any of the previous three years.


Product Information

Product ID: 5874
Production Date: 1/12/01
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.