So for the non-farmers out there here it is.
Firstly the fields are mowed, then raked up into furrows of cut grass. After that the grass silage is picked up by the forage harvester and blown into trailers.
Next the grass is taken to the silage pit, where it is rolled to compact it to release unwanted air. It will then be covered by black plastic sheets and kept as winter feed for the cows. And they love it!