Global Spatial Database of Agricultural Land-use Statistics
Contains data for many different agricultural products, e.g., rice and maize, throughout the world broken down by country’s state level. Data are from 1980s until present.
National Agricultural Statistics Service (US)
The main site for current and historical agricultural statistics. Hard to find GIS data per se, but again, tabular data can be downloaded by state and county.
NASS is producing CropScape – a satellite derived GIS raster data set for cropland cover in the US.
Natural Resources Conservation Service (USDA) Geospatial Gateway
Interactive map gateway to ordering USDA data including soils, precipitation, temperature, and orthphotos (including National Agriculture Imagery Photography – NAIP – products).
U.S. Census of Agriculture
The US Census of Agriculture takes place every five years and reports agricultural data aggregated by county and state.
We haven’t tested out the 2007 Census of Agriculture query tools extensively yet for compatibility with GIS, but the general concept holds that you will get data by county in a spreadsheet or .CSV format and should then in principle be able to join that data with a county boundary GIS data set.
The 2002 Census of Agriculture information is available for download into GIS formatted tables. Instructions:
1. Go to 2002 Census of Agriculture Query by State and County site
2. Select the data that you want and the geographical area you are interested in. Once you have made your selections, hit the get data tab.
3. At the end of the table that results, there is an option to “Click here for a GIS version of this output.” On the next screen you must choose download dbf, txt, or all GIS files. Getting the DBF file will provide a table that includes the State and County FIPS codes combined. This can be joined to US county boundary files (One source for the county boundary files with basic Agricultural Census data is at the National Atlas site – read the note below).