This polygon shapefile contains areas of important farmland in Marin County, California for 2010. Important Farmland Maps show the relationship between the quality of soils for agricultural production and the land's use for agricultural, urban, or other purposes. A biennial map update cycle and notation system employed by FMMP captures conversion to urban land while accommodating rotational cycles in agricultural use. 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. For environmental review purposes, the categories of Prime Farmland, Farmland of Statewide Importance, Unique Farmland, Farmland of Local Importance, and Grazing Land constitute 'agricultural land' (Public Resources Code Section 21060.1). The remaining categories are used for reporting changes in land use as required for FMMP's biennial farmland conversion report. This layer is part of the 2010 California Farmland Mapping and Montoring Project. The Farmland Mapping and Monitoring Program (FMMP) provides data to decision makers for use in planning for the present and future use of California's agricultural land resources. The data is a current inventory of agricultural resources. This data is for general planning purposes and has a minimum mapping unit of ten acres. The Important Farmland survey area is based on Natural Resources Conservation Service (NRCS) modern soil surveys covering most non-governmental lands in California; 49 counties are fully or partially surveyed at this time. Soil surveys specific to National Forests or other government land units are not surveyed. Beginning in 2000, SSURGO digital soil information was incorporated into the Alameda County Important Farmland data. Data subsequent to 2000 may have acreage and soil line differences due to incorporation of newer NRCS-SSURGO editions.
Prior to the availability of SSURGO, soil information was hand-transferred from the paper soil surveys. Older versions of the data have not been modified. The land use minimum mapping unit of ten acres has not changed, but digital soil units of down to one acre occur in the SSURGO-enhanced Important Farmland data. Due to the interaction of land use and soil components of the data, incorporation of SSURGO may also result in units of less than ten acres for categories such as Other Land (or Nonagricultural and Natural Vegetation). For more information on SSURGO, contact the USDA-Natural Resources Conservation Service: <http://www.nrcs.nrcs.usda.gov/wps/portal/nrcs/main/soils/survey/geo/> This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.
