Icy ploughing

Took the camera out on the dog walk this morning to get some frosty photos and was surprised to see the tractor out, turning the part of a field which has been unfinished since before Christmas.

In discussing the matter with the dog, we concluded that the ground probably needed to be relatively hard else the tractor would sink which is why they had chosen to do it today.  

I'm sure someone out there knows if that is a plausible explanation..

Have to say, this morning was a pleasure, I prefer frost and ice a million times more than rain and mud.