A permanent wetland such as a slough or swamp has advantages. Most of these natural duck holes have been there for generations, and migrating ducks and geese return to them year after year.
Many crop fields must be pumped, though, and that water is provided by fuel and wells. It’s not cheap to flood a field. If your field must be artificially flooded, be sure that oft-hidden expense is discussed up front. Some leases have “guaranteed” water built into the contract, but even then, be explicit on who is in charge of, and pays for, the pump timing, the water-control structures, and the draining of the field after the season. Dry years may require more than one pumping to maintain water levels.