A haulm topper is an agricultural machine that cuts potato stems (haulms) before potatoes are harvested. It is like a flail mower but has the profile of the potato drills. Modern potato farmers often mount a haulm topper on the front of the tractor and have a trailed potato harvester towed behind the tractor. Toppers can also be rear-mounted.
Media related to [//commons.wikimedia.org/wiki/Category:Haulm_toppers Haulm toppers] at Wikimedia Commons