Straw

Not hay or alfalfa... only the stems of cereal grains, like wheat or rice, with the seed removed... properties: high carbon, low nitrogen, strong cellulose fibers, tensile strength, good insulation, versatile material, mixes well straight or chopped... low ecological footprint, straw is a by-product of agriculture, and is normally burned... used in landscaping, straw-bale, cob, straw-clay, earthen plaster, animal bedding, and compost...