Seeding alfalfa in old pasture

Hi guys,

 

Just found this site and you guys have a great wealth of information here. Hope you guys can help me out. I seeded about 160 acres of alfalfa this year into land that had been seeded in to grain for a long time. It's been doing fine except for the real dry spots and some weeds. I have about 70 acres of pasture that I want to seed to down to alfalfa and I'm not sure the best way to go about it. Some guys advise to break up the pasture (with a breaking disc, terra disc and harrows) now and seed in the spring. My concern with this is weeds seeds that will germinate. The pasture right now is mainly just native grass (they call it buffalo grass) but there are no weeds at all. I was thinking if I mowed this right down to the ground now and in the spring again, then i could just use a disc drill to seed right into the pasture and limit the amount of weeds that come up. What do you guys think? Thanks in advance.

Seeding alfalfa in old pasture