Straw refers to the stems and leaves (spikes) of mature crops. It typically refers to the remaining parts of crops such as wheat, rice, corn, potatoes, rapeseed, cotton, and other crops after the seeds have been harvested. Straw is a versatile renewable biological resource and a coarse feed material characterized by a high crude fiber content (30%-40%) and containing lignin. It has a high calorific value and can be crushed and compressed into fuel.