Or like airships, floating above the crops and only touching it with the whatever devices are used... Fun aside, agricultural devices on rails are not uncommon, although definitely not for such large areas like a normal field (yet?).
Actually a dirigible fixture could probably reduce the weight on the wheels by an order of magnitude for (relatively) little cost. Assuming little maintenance for the dirigible fixture and reduced maintenance for the smaller drivetrain, this might actually make financial sense. But it would require a hanger for parking.
