Drilling orchard grass in thick alfalfa

Hey guys this is my 2nd year on my round up ready alfalfa. The stand is thick and looks good, but I'm quickly finding out you can sell 10 bales of alfalfa orchard grass for ever one bale of pure alfalfa. Haven't had any weeds since spraying the spring of last year, couldn't believe how fast the Johnson grass died out!! Was really happy!! I probably won't but if I decided to drill orchard grass in it this fall would the new orchard grass be able to compete in a thick stand of alfalfa or would it smother it out? Also would it increase my yield over just pure alfalfa?

Drilling orchard grass in thick alfalfa