if it's like a field that i worked over before, this is what i did. there were lots of saplings and vines in the area. i bush hogged it. then i went over it with a box blade. i used the shanks to break up the soil and pull out LOTS of roots and stumps. by LOTS i mean that i would have coffin sized hunks of root matter that would accumulate in front of the shanks of the boxblade. it broke up the soil fairly well too.