drawn along and powered by an agricultural tractor 1 running on ground wheels 2 provided at both sides of the baler in its lower front region there is a pick up device 3 for picking up crop lying on the field and for feeding the picked up crop rearwardly and upwardly the pick up device 3 is of a construction known per se the baler comprises two side walls 4 which are constituted by mutually parallel plates spaced apart transversely of the intended direction of operative travel a between the side walls 4 is defined a coiling space 5 in both embodiments of fig3 and 4 the coiling space 5 is bounded at the bottom rear top and front at least when it contains a completed bale by lower driving rollers 6 rear winding elements 7 and front winding elements 8 the rollers 6 and the winding elements 7 and 8 can all be powered from the tractor drive to the rollers and the winding elements is transmitted from the front of the baler on the outboard side of one of the side walls 4 an auxiliary shaft 9 connected with a power takeoff shaft of the tractor 1 provides the input to a drive casing 12 situated at the front of.