Straw Bale Homes
Straw is a waste product, and after the consumable portion has been removed, it is usually added to landfill or burned. By using it as a structural or insulation component in a building, agricultural waste can be made useful. Straw from wheat or rice is the most common form found, and can be found cheaply in agricultural regions, where it would make the most sense to build these structures (to avoid extensive shipping costs and the environmental impact therein).
ArchDaily has an article that highlights some of the benefits and drawbacks to this low-impact style of building.
The bales can either be stacked into traditional framing (timber is common) as insulation, or can be used as a self-supporting structure, called the "Nebraska" style. A series of compacted bales of straw can support enough weight to safely construct a long lasting one-story home.
There are some drawbacks, primarily the increased wall thickness of a straw bale house, and possible water intrusion. Typically straw bale structures are built on raised foundations, coated in stucco or cement, and are built with large eaves to prevent excess moisture on the outside walls. If moisture intrusion does occur, it can cause mold or structural issues.
Built well, a straw bale home can save an estimated 75% in heating and cooling costs, and is considered fire-safe. When a house has finished its useful life, it can be torn down and reincorporated into the land with minimal environmental disruption.