Hard pan can sure he an issue with some of my areas. I have seen deer around a feeder cause tremendous compaction which resulted in limited vegetation growth when planted. I use a ripper about every 3rd year in red clay. It definitely makes a difference with moisture. A corn field that was half paratilled and the other half nothing done made a believer out of me. There was a dividing line in the field where at least a 2 ft difference in height. As for a plow in red clay, I prefer a disc plow (or fire break plow or tiller plow or whatever you choose to call it). Only when I feel its needed. In some sandy fields, I just disc them.