Years ago I build a mini drag section out of angle iron and re-bar to pull behind a riding mower or atv.
Take 12' of 3-4" angle, cut it into 4' qt2 and 2' qt2. Weld then in a rectangle. Cut a lot of 7-8" peices of re-bar (or round bar stock) and weld them place as teeth that will enguage the ground.
Spray and mow SHORT (or spray and burn). Then pull the drag around till you have loose soil on top (in dry conditions). Seed and re-drag lightly.
You can weld some exta iron in the center of the rectangle to support weight if you need to add rocks,blocks, ect...
It's pretty easy to do if you access to a welder and a chop saw. If you tip the 4' sections of angle a bit before welding, the teeth will slope slightly to the rear. This will help keep them from building up with trash (round bar stock will work slightly better than re-bar). You can also flop the section over and use the smooth side for leveling. Works pretty well for a plot like you described. If your passing thru the Iowa City area, I have one you can borrow. I'll have to locate it, it's somewhere...
Jody