On 11/17/2014 2:21 PM, dpb wrote:
The origin of the species...

http://www.asabe.org/awards-landmarks/asabe-historic-landmarks/graham-hoeme-chisel-plow-38.aspx
....

I followed that a bit & came to wiki. One thing that it said was that
chisel plows require 10 - 15 hp PER shank/chisel! (Because they go so
deep - 8-10".)