Prepacked Food?

We have watched this field all summer, with great interest.

Early on, after sowing whatever it is, a gang of men descended one day and within the day covered the entire field in that horrible plastic sheeting that is so prevalent now. As the crop grew underneath, the plastic took on its own strange shape and form, with just the occasional bit of greenery escaping its confines, and waving gently in the breeze.

We think it is Oil-seed Rape, because we can see a bit of yellow from time to time, but why grow it under cover? I'm wondering if at some crucial point in the winter, the plastic will be whipped off and the whole field used as fodder?

Or, is it an experiment to see how well this stuff grows under cover?

Whatever, today there wasn't much difference between the clouds and the ground.