Underserved producers generally include beginning farmers, socially disadvantaged farmers, veteran farmers, and limited resource farmers; women farmers and producers growing specialty crops are generally also included in these categories.
Here is more detail on "underserved": https://www.nrcs.usda.gov/getting-assistance/underserved-farmers-ranchers
Here is a self determination tool for "under resourced" : https://lrftool.sc.egov.usda.gov/DeterminationTool.aspx?fyYear=2024