FMMP - Important Farmland Map Categories

About 94% of the FMMP's study area is covered by US Department of Agriculture (USDA) modern soil surveys. A classification system that combines technical soil ratings and current land use is the basis for the Important Farmland Maps of these lands. In areas where no soil survey is available, a series of Interim Farmland definitions have been developed to allow land use monitoring until soils data becomes available.

The colors and letters above are used to depict categories described below.
The minimum land use mapping unit is 10 acres unless specified. Smaller units of land are incorporated into the surrounding map classifications. In order to most accurately represent the NRCS digital soil survey, soil units of one acre or larger are depicted in Important Farmland Maps.

Prime Farmland (P)

Farmland with the best combination of physical and chemical features able to sustain long term agricultural production. This land has the soil quality, growing season, and moisture supply needed to produce sustained high yields. Land must have been used for irrigated agricultural production at some time during the four years prior to the mapping date. Download information on the soils qualifying for Prime Farmland. More general information on the definition of Prime Farmland is also available.

Farmland of Statewide Importance (S)

Farmland similar to Prime Farmland but with minor shortcomings, such as greater slopes or less ability to store soil moisture. Land must have been used for irrigated agricultural production at some time during the four years prior to the mapping date. Download information on the soils qualifying for Farmland of Statewide Importance.

Unique Farmland (U)

Farmland of lesser quality soils used for the production of the state's leading agricultural crops. This land is usually irrigated, but may include nonirrigated orchards or vineyards as found in some climatic zones in California. Land must have been cropped at some time during the four years prior to the mapping date.

Farmland of Local Importance (L)

Land of importance to the local agricultural economy as determined by each county's board of supervisors and a local advisory committee. Download a complete set of the Farmland of Local Importance definitions in PDF format.

Grazing Land (G)

Land on which the existing vegetation is suited to the grazing of livestock. This category was developed in cooperation with the California Cattlemen's Association, University of California Cooperative Extension, and other groups interested in the extent of grazing activities.

Urban and Built-up Land (D)

Land occupied by structures with a building density of at least 1 unit to 1.5 acres, or approximately 6 structures to a 10-acre parcel. This land is used for residential, industrial, commercial, construction, institutional, public administration, railroad and other transportation yards, cemeteries, airports, golf courses, sanitary landfills, sewage treatment, water control structures, and other developed purposes.

Other Land (X)

Land not included in any other mapping category. Common examples include low density rural developments; brush, timber, wetland, and riparian areas not suitable for livestock grazing; confined livestock, poultry or aquaculture facilities; strip mines, borrow pits; and water bodies smaller than forty acres. Vacant and nonagricultural land surrounded on all sides by urban development and greater than 40 acres is mapped as Other Land.

Beginning in 2002, the pilot Rural Land Mapping Project provides more detail on the distribution of various land uses within the Other Land category in four San Joaquin Valley counties.

Water (W)

Perennial water bodies with an extent of at least 40 acres.

This category was developed in cooperation with local government planning departments and county boards of supervisors during the public workshop phase of the FMMP's development in 1982. Land Committed to Nonagricultural Use information is available both statistically and as an overlay to the important farmland information. Land Committed to Nonagricultural Use is defined as existing farmland, grazing land, and vacant areas which have a permanent commitment for development.

For farmed areas lacking modern soil survey information and for which there is expressed local concern on the status of farmland, the following categories substitute for the categories of P, S, U, and L. This historically included Butte, Colusa, and portions of Kern and Tulare Counties. Due to completion of many soil surveys, Kern County is the only location which continues to have Interim Farmland data.

Irrigated Farmland (I)

Cropped land with a developed irrigation water supply that is dependable and of adequate quality. Land must have been used for irrigated agricultural production at some time during the four years prior to the mapping date.

Non-irrigated Farmland (N)

Land on which agricultural commodities are produced on a continuing or cyclic basis utilizing stored soil moisture.

Division of Land Resource Protection