[Z-Michigan]

I have a similar setup now and will be doing the same thing in the near future! BTW I posted a thread in the projects forum back in January about creating pastures. Might be an interesting read.

I would be inclined to do something to scrape up the surface - like a disc, chisel plow or field cultivator - and then plant a fast growing grass like annual ryegrass to choke out all the competing weeds. Then I would plant my perennial pasture crop this coming fall - probably a mix including alfalfa or clover, for the same reasons farmwithjunk said. They add nitrogen and have deep roots that will help aerate the soil.