This last harvest, back in Iowa, my Dad had some old waterways redone. The contractor uses D6R LGP($135 per Hr, I believe) and asked he if we were to "bushhog" and disc up the sod, he could do a much faster job and it wouldn't be so dang rough on him and his other operator. He says that with fresh sod, it just rolls up like carpet and is hard to "level out" in the field area, then is really bumpy,  in reverse, going back for the next cycle/push.

We stopped combining, Dad got on the bushhog(did get stuck 3 times), I got the disc and went for about 4-5 hours. Next day, The D6R got way more done that first day, then they expected. Dad actually had them do more dozer work than he first thought, because they could be more productive, if we worked ahead of them(on waterways).