It is a 3-photo HDR that was processed using Photomatix Pro. Other software used to complete the look included Nik Software's Color Efex Pro 4 and Topaz Adjust.
The HDR process really helped bring out all of the detail and grit in this photo. I remember when I was photographing the scene I was facinated with all of the belts hung from every possible place. The old wood door and oil drums were also of particular interest.
You can read more on how this photo was created, with before photos, here: http://www.mattsuess.com/blog/2012/6/belts-oil-arizona