Well this is the power harrow. Apparently it is most popular for organic gardening in eastern Quebec. And it is for both weed control and pest control. it controls pests by burying crop residue, but unlike a plow, does not have the disadvantage of turning the soil--which would destroy its structure, and its microbiome.
http://www.kuhnnorthamerica.co...
And here is the collinear hoe--operated by Eliot Coleman himself, on you tube:
https://www.youtube.com/watch?...
Another Eliot Coleman tool is the broadfork:
http://www.johnnyseeds.com/p-5...
And, the wheel hoe:
http://www.motherearthnews.com...
This one shows the shape of the collinear hoe's blade.
https://www.youtube.com/watch?...
