What USDA records does NAL collect versus the National Archives?

There is a detailed list of the material Special Collections collects available in the Collection Development Policy. Note that the U.S. National Archives also collects USDA material. The difference between what the two institutions collect is described in the same document.

The National Archives and Records Administration (NARA) is an agency of the United States government charged with collecting comprehensive and systematic records of all federal government agencies, including USDA.

NAL’s Special Collections unit receives collections of documents from individuals and organizations, which often are USDA scientists or subagencies. Many of these collections contain incidental copies of documents or photographs that are USDA records. These items may be present because they were of interest to the individual or organization that donated them. They do not represent comprehensive and systematic collections of official USDA records.