New alfalfa

I have about 7 acres of alfalfa.. long story short I planted 3.5 acres last fall with r/r alfalfa.. got lots of rain and most drown and didn't do well, the field was very very spotty. I decided to replant using conventional evermore alfalfa because of the price and the field was killed down very well. So this spring I no tilled the conventional alfskfs into the spotty existing alfalfa. I also worked up another 3.5 acres next to it because it was so rough and no tilled more alfalfa there. Both were seeded at 20lbs per acre. Both are coming up well but with the warm sunny weather and rain every week the grass and weeda are too. Whag can i spray on the new alfalfa to control weeds. Both plots are between emergence and 1st trifolate. The older r/r alfalfa in the first plot that survived is doing well and about 8 to 10 inches tall. Any advice? I'm new and this is my first time planting alfalfa. Lime and fertiatilty is spot on.

New alfalfa