Straw

Straw is the dry stalks of cereal crops, such as wheat, barley, oats, or rice, that remain after the grain kernels have been harvested. It is distinct from hay, which consists of cut green grasses intended for fodder. Straw fibers are relatively coarse, light, and hollow, and are composed primarily of cellulose, lignin, and silica. Because it has low nutritional value, straw is usually not eaten by livestock, though it may be used in some feeding systems as a roughage filler or bedding.

Straw is produced as a byproduct of grain harvesting. Different crops yield differently colored straw, with wheat straw often pale gold and rice straw tending to paler or darker depending on processing. In many regions, straw remains as a residue that is baled or stored for later use. It should be kept dry to prevent decay and mold.

Uses of straw are varied. It is widely used as animal bedding because of its absorbency and warmth. It serves as mulch and soil amendment in horticulture, helping with moisture retention and weed suppression. Straw is also employed in thatching for roofs, insulation in construction, and as a feedstock for bioenergy and in some lightweight packaging materials. Straw bale construction has been used in rural architecture and sustainable housing.

Environmental and safety considerations include its renewability as a byproduct, biodegradability, and potential as a low-cost insulation material. However, straw can harbor pests or mold if stored damp, and large stacks can pose fire hazards. In some places, burning straw is regulated due to air-quality concerns.