look at this if you have a few extra bucks.
http://www.basspro.com/webapp/wcs/stores/servlet/Product_10151_-1_10001_73272____SearchResults
A1 rental will have something that will work, but the pricetag for a day rental was high when I checked into it. Made it worth just buying my own. Bass Pro is $300 less for the same product vs Cabelas.
A couple years ago I decided to get the above disc for my garden and food plot and couldn’t be happier. It is heavy enough to break ground really well and built like a tank. Lighter discs and flip-discs have a harder time with less weight. No additional weight is needed with my disc. We actually had a tractor with a light disc in my food plot the year before I bought the ATV disc, and the tractor couldn’t get into the soil very well at all — although, that was partially due to some standing grass issues. The ATV disc actually did a better job of turning the ground.
It WILL till up living sod, but it does take multiple passes. If you kill everything off and mow to the ground first, you will be able to till up an awesome plot in no time. It does an amazing job on damp soils that were previously broken up.. One pass and done. If it was tilled last year, you should be good.
I’m not an expert and could be wrong, but I wouldn’t think you need to worry too much about “hard panning” your soil with an ATV/disc. From what I understand, that is more due to the weight of today’s big tractors. Could be wrong though.