I basically stripped all the controls, removed the chain, sprocket, crank, seat tube, front fork, and handlebars. Then I cut it in half in front of the vertical tube and used one of the leftover framing tubes to form the main upright of the hoe. To make the upright a bit longer, I used the "steering column", removed from the frame and cut just above the front forks. Then I was able to re-insert the handlebars into the steering column and have a little bit of adjustment as to where and how the handlebar is oriented to the main column. Something like this:
This first version was "quick and dirty" and the tool was mounted on a piece of soft steel bolted to the kickstand mounting plate. The springiness of this mounting was actually quite pleasant in the field, but it was just an interim step while I waited for a stirrup hoe and turning plow to arrive from Hoss, a manufacturer of commercial wheel hoes. These attachments cost about $20 each. Here is the mounting I created for the Hoss attachments:
This bike had 20" wheels and a proportionally-sized frame (not sure how bike frames are measured). The upright that I fabricated could be a bit longer, but it's fine the way it is. The greatest barrier to someone trying this is the need to weld thin-wall tubing, which can be tricky. I used gas welding, of course, tig welding would be ideal. This type of tubing usually responds very well to bronze brazing, although this takes more preparation and tighter fitting joints to work well. I brazed the upper joint and it came out really ugly and globby for some reason. But brazing might be easier for someone who is not as comfortable welding tubing.
There are obviously many permutations regarding how the tool is mounted, but it's clear to me that it works best when the tool is up close to the wheel. A piece of square tubing welded to the bike frame would work well. I'm wondering if it wouldn't be possible to use the seat tube to mount the tool, thereby having a very quick height adjustment. The seat tube in it's original position does not point in quite the right direction for this, but there may be a way to weld a new seat base tube into position and use this approach.
Good luck with your own project, I hope this information has helped you a little.