Oh boy, those are big time trouble and to my knowledge the best solution is a Pre-emergent like Simazine or Princep-80. First off I would suggest that you contact your local county agent for help.
I had a 150 acre hay meadow years ago and about 1/3 got infested with "grass spurs" and it took several years and several application with the above to eradicate it completely.
Good luck, Thomas
