An agricultural combine comprising: a threshing system; a sieve positioned and configured for receiving crop material containing grain from the threshing system and allowing the grain and smaller elements of the crop material to pass through the sieve while guiding and propelling a flow of larger elements of the crop material past an edge of the sieve; a crop material distributor disposed between the threshing system and the sieve, configured and operable for distributing the crop material from the threshing system onto the sieve; a sensor (42, 48) configured and operable in response to sensing information representative of at least one of a quantity of grain associated with the crop material distributor and an inclination angle associated with the crop material distributor and outputting signals representative thereof; an apparatus operably associated with the crop material distributor, including an actuator configured and controllably operable for positioning the apparatus; and a control system connected in operative control of the actuator, and the sensor (42, 48) for receiving the signals outputted thereby, wherein the control system is operable for controlling the position of the actuator for positioning the apparatus, characterized in that the apparatus extends substantially transversely with respect to the crop material distributor and is positionable by a rotational movement about a rotational axis that extends substantially transversely with respect to the crop material distributor between a first angular position and a second angular position with respect to crop material distributor for providing an increasing impediment with respect to crop material moving toward the sieve. a threshing system; a sieve positioned and configured for receiving crop material containing grain from the threshing system and allowing the grain and smaller elements of the crop material to pass through the sieve while guiding and propelling a flow of larger elements of the crop material past an edge of the sieve; a crop material distributor disposed between the threshing system and the sieve, configured and operable for distributing the crop material from the threshing system onto the sieve; a sensor (42, 48) configured and operable in response to sensing information representative of at least one of a quantity of grain associated with the crop material distributor and an inclination angle associated with the crop material distributor and outputting signals representative thereof; an apparatus operably associated with the crop material distributor, including an actuator configured and controllably operable for positioning the apparatus; and a control system connected in operative control of the actuator, and the sensor (42, 48) for receiving the signals outputted thereby, wherein the control system is operable for controlling the position of the actuator for positioning the apparatus, characterized in that the apparatus extends substantially transversely with respect to the crop material distributor and is positionable by a rotational movement about a rotational axis that extends substantially transversely with respect to the crop material distributor between a first angular position and a second angular position with respect to crop material distributor for providing an increasing impediment with respect to crop material moving toward the sieve.