Abstract: The present invention relates to a mechanical weed seed management system and device for use on a harvester. The device comprises a plate to separate straw waste from chaff waste after their discharge from the harvester; a chute to catch, direct, and deposit the straw waste to the ground; and an annular trough comprising a means for transporting material through its length, for catching, transporting, and depositing the chaff waste on top of the straw waste on the ground, wherein the trough is of a depth greater than 150 mm, and wherein the plate directs the straw waste from the harvester to the chute. The system for the management of weeds in farmable land comprises the device.