I would rent a decent size dozer with teeth on the bottom of the blade that rips up anything to about 6" below the surface & have it done in no time. Or build an attachment like it for your bobcat. The problem is you may never use it again.
' below the surface & have it done in no time
"The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich theory of life." Theodore Roosevelt
Freedom is never more than one generation away from extinction. We didn't pass it to our children in the bloodstream. It must be fought for, protected, and handed on for them to do the same. - Ronald Reagan