State agricultural agents.

For economics, university agriculture departments.

Were I interested in such a thing, I'd probably approach local farmers' markets and CSAs with an eye toward pivoting that contact in to generational or institutional farmers if that were the interest given that the smaller folks are both more approachable (many have websites with contact info) and likely to have contacts with their big shot neighbors.

If you're not a big enough entity to garner interest/respect to get over the suspiscion your likely to need an introduction to speak to anyone managing more than maybe 100 acres because it is a massively competitive industry with wildly low margins that lead to a sort of "what's in it for me" kind of paranoia at the higher end.

That said, talking to locals at a local farmers' market, I've never run in to any kind of push back, but that's largely due to my making it clear that I am a hobbyist who presents zero risk to their operation. The moment they get any whiff of "this person might be researching optimizations for their own pepper/pumpkin/mushroom operations" the trail goes cold.