English: Tractors at work. The device operating here is a forage harvester. The grass would have been cut a few days previously but instead of being dried off to make hay, it is being lifted while it still has a bit of sap in it. The grass will be placed in a pit then covered to exclude air. Under these conditions, the grass keeps better and turns into silage which is used to feed animals in the winter. Larger farms tend to bale the grass and wrap the individual bales in plastic sheeting. This has the same effect but the bales can be left out once they are wrapped. (We are grateful to Geograph member Ag for this explanation)