A down pressure assembly for incorporation into an agricultural implement to be pulled by a tractor (10) has an attachment frame (21) for attachment between a portion of the agricultural implement and at least two wheels (22) of a row unit (18) for traveling along the ground, the row unit (18) also having a tool (23) disposed between the two wheels (22) for engaging the ground, the down pressure assembly also having at least one torsion element (41, 50) disposed on the frame (21), with the torsion element (41, 50) having one fixed mounting to the frame (21) and one adjustable mounting to the frame (21), and the assembly further having an adjustment mechanism (37, 60) for varying the torsion of the torsion element (41, 50) at the adjustable mounting; and at least one down pressure member (36, 56, 57) for receiving a force from the torsion element to apply a downward force to the top members (26, 27) of the frame (21).