I have a wild field and there is an organic farmer further down the road, but we rarely have such beautiful fields. I mostly get grasses, dandelions, and thistles with the occasional daisy (although I did have a single poppy one year) - probably because I'm just mowing it and not removing plant material. The farmer had a rather pretty field full of cow vetch and a few daisies last year. It attracted loads of butterflies. :)

Seems like I need to come to the UK for the really gorgeous fallow fields. :)