This 'n' That

Overheard:

TV Voice: "Just what brought ancient man to Amesbury?"

Chairman: "The A303!"

Later:

Chairman: "Did you read that story about a boy in India having a 20cm vestigial tail surgically removed?"

Hay: "Weird bits of DNA from our distant past keep cropping up - you occasionally get people covered in a thick layer of hair, for example. Just look at yourself, for a start."

We were travelling through the countryside yesterday on the way back from the garden centre in Nailsworth, through acres of fields of stubble from this year's crops, and it struck me that if wheat is a variety of grass, then why when it's cut do farmers need to plough the fields and plant new seed? Surely it should just grow again from the roots, like my lawn?

I understand that wheat, unlike wild grasses, retains its seeds and hence it's difficult to reseed a field naturally, but then my garden lawn never even gets to seed stage, yet it continues to grow from year to year without self-seeding. Perhaps a farmer can explain? Must be something to do with the root system.

The same goes for other crops. I can hack weeds down in our field, and they keep coming back year after year. Why not cabbages? Perhaps they would, but they wouldn't be as vigorous?