Yard Sale?

When I drove to work this morning, I saw a row of farmyard equipment set out in this field. And on the way home in the evening, there were signs saying "Car Park" and pointing to the field opposite?

What can it be? Was the equipment being sold? Was there a ploughing competition or some such on the go? I have no idea, but as an occcasional listener to The Archers I really want to find out!