carrots etc. to manure or not?

hi all, i've just got an allotment, and never done this before. i've startd to double dig adding lots of well rotted manure for next spring's growing.
the thing is do i or do i not add maure to my root area where i'am going to sow my carrotts, potatoes etc next year as one book says don't and the other says do if it hasn't been dug before
so do i or don't i ??
thanks for any help.

I understand carrots and parsnips and onions should be treated differently from spuds - read John's rotation info on the information pages!

M