If you're subleasing the ground from the dairy, are you paying the going rate? Do you get paid for hauling their manure? Get the manure free for the hauling?

Lots and lots of ways for things to be done. If you feel like you need better communication, call them and set up a time for a meeting. Explain to them, calmly and with facts, how you think you need a better deal. Some arrangements don't last, some do.

 Maybe you should offer to hire on as crop manager? Seems like now all they have done is transfer all the crop-growing risk to you, without the potential for reward.