Was at the Turriff Agricultural Show in North East Scotland today. The largest tractor on display was the Fendt 1050 Vario with a 510hp engine. It weighs at least 14tonnes before fitting any attachments. The skilled labour force in agricultural is declining, given the appropriate attachments and implements these tractors are capable of prodigious output in a day. In my lifetime tractors have changed out of all recognition. The Massey Ferguson 185 I drove at 17 had only 75 hp and had none of the creature comforts of these monsters. The size is limited by traffic regulations, any wider and movements on roads could require notification to the police.
The argument always was that the machinery replaced men, my view is that the increasing mechanisation has been because it has become much harder to find people willing to do farm work.