The modern way of ploughing in the UK is the same you start at on side with a reversible plough and work until you are finished
Competition ploughing in the other hand is different
This stems from the bygone days when horses were to the fore with some tractors ploughing
the 28th of November was what was called Fee day if a farmer wanted to keep you on for another year you got a fee shilling 5p in today's money
The one way to prove to an employer or potential employer that you were of high calibre was to show the pride you took in your ploughing, your horses or tractor.
This was one of the reasons ploughing matches were held ,farmers took great pride in telling everyone how good you were and it was there for all to see.
There was great banter between ploughman great musical nights in the bothies on all the farms this was when the men praised the best ploughman and encouraged the young lads to follow on
Today some tractor-men ploughing now do not and have never worked on a farm but the carry on the tradition
all about having fun
Hope this helps you