The present invention relates to a baler with a bale forming chamber in the halm- and / or sheet-like crop or similar pressed material bale form and / or can be pressed, wherein the bale forming chamber has at least one circulating around pulleys belt element, which can be tensioned by at least one belt tensioner and is driven by at least one drive rotor. The invention further relates to a method for controlling a baling press. It is proposed to monitor the slip between the at least one belt element and the at least one drive rotor and to control at least one operating parameter of the baler depending on the slip occurring.
