An apparatus and method for processing a crop residue, which includes but is not limited to, destroying weed seeds present in the crop residue. The apparatus (10) comprises an elongate housing (12) having an inlet (20) for receiving crop residue and an outlet (22) for discharging the crop residue. The apparatus (10) also has one or more rotors (24), (26) located in the elongate housing (12). Each rotor (24), (26) comprises a plurality of radially extending impact members (28a), (28b), (28c), (28d), (28e), (28f) which rotate with the one or more rotors (24), (26) and impact against the crop residue, so that lighter material of the crop residue is subjected to less impacts and denser material of the crop residue is subjected to relatively more impacts.