Im going to offer the oddball advice.
Unless you have intentions of leasing out the field for $90 to $100/ acre to a local farmer, COMBINED with the fact you are bordered by current ag land, I would NOT convert that 20 acres into ag...
What i would do... thin the holy crap out of those pines (take the stand down to less than 100 basal ft per acre), have the crew install fire lanes around the perimeter, then id regularly burn that joker every other year to promote a pine savannah with tons of natural grasses under the pines. Save a couple acres to disc annualy and promote forbs, then maybe have an acre food plot to play with. You will have WAY more game to hunt if you do that versus 20 acres of open ag.
Oh, another thing... just price out what it will cost you every single year to plant corn or beans on 20 acres to leave for wildlife. That alone will stop you from converting to ag.