The Department of Agriculture Web site (www.usda.gov) posts lots of information about U.S. agriculture with links to related Web sites. AgricultureLaw.com and the National Agricultural Law Center post many more links to good agriculture sites.
Westlaw has an Agriculture News database (AGRINEWS).
To search for published materials, try the National Agricultural Library Web site (www.nal.usda.gov), which includes access to the library's online catalog and various "Centers" that provide answers to agriculture-related reference questions.
ALJ Orders: Orders issued the the USDA's Office of Administrative Law Judges are posted back to 1998 on the USDA Web site (www.usda.gov/da/oaljdecisions). Older decisions are available from the Office of the Hearing Clerk (202-720-4443).
Judicial Officer Decisions: Summaries of decisions by the USDA's Judicial Officer back to 1971 are posed on the Web page of the Office of the Judicial Officer -- scroll down to the link at the bottom of www.usda.gov/da/ojo.htm.
Foreign Laws: FAOLEX summarizes (and often provides English translations of) the agriculture-related laws of FAO member nations.