The Agriculture function covers USDA programs that support farmers and rural America — about $32 billion in FY2024. Note this excludes SNAP / food stamps (those are in Income Security) and farm-program income support that's classified separately. The biggest line is the Farm Service Agency (~$15B) — farm income support, crop insurance subsidies, commodity loans, and conservation payments to landowners.
Other significant pieces: USDA's Natural Resources Conservation Service (~$4B) for soil and water programs and wetland reserves; Agricultural Research Service plus cooperative state extension (~$3B) for federal ag research labs; Animal and Plant Health Inspection (~$2B) for pest and disease control; and rural development programs (~$8B) including USDA broadband, rural energy, and rural housing.