Gliding operations during the day had been conducted on Strip 19. On this occasion the pilot planned to approach to that strip but to land on the cross Strip 09, to allow the glider to complete its landing near the club hangar. During the turn onto final approach, to Strip 09, the pilot noticed a tug aircraft apparently making an approach to the same strip. He continued his turn in order to avoid any conflict with the tug, and the aircraft subsequently touched down across Strip 19. It then ran through a ditch before colliding with a fence. The tug pilot stated that he saw the glider and thought that it would land on the left side of Strip 09. The tug aircraft was not fitted with a radio which denied two-way communications between the two aircraft. The two aircraft came into close proximity and the glider lost excessive height as the pilot forgot to retract the airbrakes during the turn to avoid the tug aircraft. The tug pilot continued the approach and landed but the glider pilot was committed to a downwind landing and attempted to land across the other strip.