100% is an asymptotic goal, because someone still has to do the maintenance. But grain is probably closest, along with maize and soybeans. Staple crops, huge farms, single guy in a tractor, and the monotonous driving is already being automated away too. Leaving the role of the human to arguing with John Deere over right to repair.

Soft fruit is probably furthest away. That depends on huge armies of immigrant pickers.