A flow distribution system (40) for use with a combine spreader (24) has an inlet opening (45) for receiving crop residue, a pair of counter-rotating impellers (28, 30) comprising spreader paddles (70) disposed generally side by side and forward of a back plate (36) of the spreader, and a discharge opening below the spreader paddles. A flow guide element (42) has an apex portion (44) and a pair of opposed arm portions (46, 48) pivotally connected to the apex portion, the arm portions laterally extending to free end portions (50, 52). An adjusting mechanism (78) is operably connected to the arm portions (46, 48) to effect rotational movement of the arm portions about the apex portion, ends of spreader paddle members defining the outer swept diameters of the spreader paddles (70) and the crop residue flow surfaces of at least the arm portions defining clearance regions (67) therebetween to controllably distribute crop residue in a desired pattern over a field. The clearance region includes at least one undulation (66) formed in the arm portions (46, 48).
