A chopper for receiving the straw and/or chaff from a combineharvester includes a housing with a chopping rotor to transport the materialsthougha discharge opening onto a tailboard construction with downwardly facing guidesurface and fins for spreading of the crop materials. A rotary spreader has aplurality of fan members with blades rotatable for discharge to a respectiveside ofthe rotary spreader. An arrangement is operable so that in a first mode thecropmaterial is spread wholly by the tailboard and in a second mode the cropmaterial isspread at least mainly by the rotary spreader. In the second mode thetailboardremains position above the rotary spreader which is therefore locatedunderneath aguide surface with fins of the guide surface facing downwardly adjacent theblades.The movement to the second ode is provided by the rotary spreader being movedforwardly and downwardly.
