I've got cheat grass in my new stand of alfalfa.  The cheat grass has come in where the ground is lighter.  Anyway the cheatgrass has just started to head out.  Any good ideas on how to get rid of it in my alfalfa before the seed becomes viable?

I also have cheatgrass in my pasture.  My pasture is a mix of brome, timothy, clover, warm season grasses and some alfalfa.  I have looked into the grazing option, but the areas are so small and spread out that I'm not sure I can graze all of the spots out efficiently enough to be effective.