Calling All Farmers

We were in a tea room in Ramsbottom yesterday afternoon and in the field next door was a man in a tractor going up and down dragging a heavy roller. The field was very steep and full of meadow grass and seemed to be good for nothing but grazing. So what was he doing it for?

Ailz came up with two possible explanations: 

1. He was flattening out the mole hills so his cows (or horses or sheep) wouldn't stumble and break their legs.

2. He was compacting the soil so it wouldn't crumble and sheer away and slide off down hill.

I favour the first explanation.

Does any one out there  have any other/better idea?