This is actually a photo of Cereus hildmannianus ssp. uruguayanus instead of Echinopsis pachanoi.
I can tell because of:
the number of ribs;
the thickness and depth of the ribs;
the angle in which the side branches are growing from the older stem;
The fact that the side branches have quasi-segmented growth.
Compare with these photos here: http://davesgarden.com/guides/pf/go/103189/
Would you like like photo moved to the right page?
One more question...
The spines are shorter than 1/4", aren't they?
If they are, then this would Not be the subspecies 'uruguayanas'
It would just be the regular species (Cereus hildmannianus) http://davesgarden.com/guides/pf/go/64592/