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.
But you'll see protection mindsets at the local level too. Neighbors will lie about which seed they used, how much fertilizer, yield, etc, but not always. Like, someone who does cattle might be more free with their information when talking to a corn/soy farmer. Or take someone like a pepper farmer: a competing greenhouse is more likely to get stonewalled than a hobbyist who's just trying to understand why their fruits are small.
That's all I'm saying, I guess, is it's all in the approach. You'll get more traction from genuine curiosity than "I am building/selling this thing"
For economics, university agriculture departments.