oilseed rape

A garishly yellow plant that farmers (in the UK at least) often grow as a cash crop.

It is my suspicion that the farmers are actually paid by the government simply to grow it not to harvest it, as it is a common experience now when driving through the English countryside to be exposed to the acrid smell of rotting oilseed rape.

Also the source of many people's hayfever problems in the UK. Oilseed rape, also called rapeseed daown in thoise paaaaaaooorts, is originally descended from a poisonous plant, and its pollen is still highly irritating. In rural Oxfordshire, one may spend September to February with 'the winter sniffles', only to be attacked by rapeseed once March rolls around.

It's a plot, probably devised by the milk marketing board.