Spader

Spaders look like a really smart (60 yr. old) idea. They don't leave a "hardpan" at all due to the somewhat random action of the spades.

Spader history: http://www.ferrari-tractors.com/spade_article.htm

Spader setup and operation: http://www.ferrari-tractors.com/products/spader.htm (Note 3rd pic down. It's the soil "pulverizer" after the spades. Spades dig first, "pulverizer" breaks up the clods and makes seed bed. (Imants use a roller with curved tines instead). Does it all in one operation. Looks almost exactly like your tines on soil pulverizer.

Spader Info: http://www.winebusiness.com/wbm/?go=getArticle&dataId=47243

At the bottom of that page a reader suggests Imants spaders from Holland:

"Imants produces a spader that achieves the same results based on a different mechanical approach"

The Imants use circular "arms". They supposedly will leave a hardpan like a tiller (eventually). I'm sure they run smoother/longer though.

Good spader video. Shows the Imants final roller with tines: http://www.youtube.com/watch?v=ycadZjZ1Vnw

He discusses the mechanism up close.

Another from University of Vermont DVD: http://www.youtube.com/watch?v=uQElJLlng9M&feature=related

Celli spader with "shovels"

Spaders are incredibly expensive as they are all made in Italy/Holland etc. Inventing an open source spader would be a great achievment. They are a one pass type of implement. Working in cover crops easily is what us independents need to do. Towing the spader behind LifeTrac would be easy as spaders are not a real load on the tractor/machine. All you need is slow hydrostatic drive. But you guys got that covered ;)