A system and method for controlling spreader output from a harvester includes a distribution chamber for receiving an agricultural material removed from a field. The harvester includes a spreader system configured to distribute the agricultural material onto the field, and an opening configured to receive the agricultural material from the distribution chamber. Moreover, the distribution chamber includes a first panel rotatably coupled to a first side of the distribution chamber, and a second panel rotatably coupled to a second side of the distribution chamber. The first and second panels are configured to direct the agricultural material toward the opening of the spreader system. An angle of the first panel is independently adjustable to control a first amount of agricultural material directed toward a first inlet portion. An angle of the second panel is independently adjustable to control a second amount of agricultural material directed toward a second inlet portion.
