The people can assemble. Having assembled they have their other rights. You do not have to allow corporations at all. Bad idea, but you could ban them. You couldn't ban group economic activity altogether though. Nor could you ban group protests, political parties, community groups, etc. You also can't ban a group from getting together to be a social club and also to be a political. All a corporation is is a group of people getting together to do some economic activity. You don't have to permit that group the various extras like limited liability that corporation get. But you can't take away the rights that those people enjoy individual or collectively either.
Lack of corporations doesn't deprive anyone of liberty in the same way that failure to exist doesn't deprive the person who never existed his liberty. There's nothing tortuous or fantastic about this reasoning. People have rights. People organize. People still have rights. Pretty simple. Corporate personhood doesn't matter. A corporation doesn't have rights because it is a person, but because it is a group of people. The whole personhood thing is just a useful abstraction because the corporation acts as a unit.
As I said I know nothing other than what you've stated about the farming laws. I assume there's a lot more to it that "corporations can't run farms" since that would be unconstitutional. And no, I have no idea what that might be.