I bought a Disk from Roth Manufacturing in Loyal, WI similar to the one you're looking at judging by the picture. The Roth Disk Harrow can be adjusted to dig down agressively or to just slice the soil. I've had no problems turning forest clearings into nice food plots. Takes a few passes and raking away the debris but well worth the inventment. Here's a link of the unit I bought: http://www.usagnet.com/loyal-roth/Multi_Use6.html

My brother is always borrowing it to work his food plots and it's holding up rather well.

Good Luck.