Called a “culticycle”, it is build from an ATV, lawn tractor and bicycle parts. They’ve made several iterations of the design and it looks pretty easy to operate. You can see where it could be adapted to a variety of specific needs depending on how it is outfitted. Farm Hacks also points out it has less soil compaction that heavier fueled tractors.
It seems this design could be adapted to two people to increase the power and/or width of the tractor.
Clearly this design offers a more sustainable option for farming and gardening and will reduce your dependence on fuel.
See more over at FarmHacks.org. They offer a list of parts, some drawing and you can stay up on the progress of this design and other interesting farm innovations.