An agricultural planter having a plurality of row units, each row unit including a row unit frame, opening discs for opening a trench in the soil as the planter is pulled through a field, and gauge wheels for setting a depth of the trench, the planter comprising a system for applying downforce to the plurality of row units, the system comprising: a first actuator, said first actuator disposed to apply force to a first row unit, said first actuator including a first down chamber and a first lift chamber, pressure in said first down chamber tending to oppose pressure in said first lift chamber; a second actuator, said second actuator disposed to apply force to a second row unit, said second actuator including a second down chamber and a second lift chamber, pressure in said second down chamber tending to oppose pressure in said second lift chamber; a first downpressure control device in fluid communication with said first down chamber for controlling pressure in said first down chamber, the first downpressure control device comprising a pressure reducing-relieving valve having a pressure port in fluid communication with a fluid supply line, a tank port in fluid communication with a fluid return line and a work port connected to the first down chamber; a second downpressure control device in fluid communication with said second down chamber for controlling pressure in said second down chamber, the second downpressure control device comprising a pressure reducing-relieving valve having a pressure port in fluid communication with the fluid supply line, a tank port in fluid communication with the fluid return line and a work port connected to the second down chamber; a lift pressure control device in fluid communication with said first lift chamber and said second lift chamber for controlling pressure in said first lift chamber and said second lift chamber the lift pressure control device comprising a pressure reducing-relieving valve having a pressure port in fluid communication with the fluid supply line, a tank port in fluid communication with the fluid return line and a work port connected to the first and second lift chambers; and a processing circuitry in electrical communication with a solenoid associated with each pressure reducing-relieving valve of said first downforce control device, said second downforce control device, and said lift pressure control device, said processing circuitry configured to modify an operating state of said first downforce control device, said second downforce control device, and said lift control device by sending an individual control current to each pressure reducing-relieving valve to cause each pressure reducing-relieving valve to set a pressure proportional to the associated control current. a first actuator, said first actuator disposed to apply force to a first row unit, said first actuator including a first down chamber and a first lift chamber, pressure in said first down chamber tending to oppose pressure in said first lift chamber; a second actuator, said second actuator disposed to apply force to a second row unit, said second actuator including a second down chamber and a second lift chamber, pressure in said second down chamber tending to oppose pressure in said second lift chamber; a first downpressure control device in fluid communication with said first down chamber for controlling pressure in said first down chamber, the first downpressure control device comprising a pressure reducing-relieving valve having a pressure port in fluid communication with a fluid supply line, a tank port in fluid communication with a fluid return line and a work port connected to the first down chamber; a second downpressure control device in fluid communication with said second down chamber for controlling pressure in said second down chamber, the second downpressure control device comprising a pressure reducing-relieving valve having a pressure port in fluid communication with the fluid supply line, a tank port in fluid communication with the fluid return line and a work port connected to the second down chamber; a lift pressure control device in fluid communication with said first lift chamber and said second lift chamber for controlling pressure in said first lift chamber and said second lift chamber the lift pressure control device comprising a pressure reducing-relieving valve having a pressure port in fluid communication with the fluid supply line, a tank port in fluid communication with the fluid return line and a work port connected to the first and second lift chambers; and a processing circuitry in electrical communication with a solenoid associated with each pressure reducing-relieving valve of said first downforce control device, said second downforce control device, and said lift pressure control device, said processing circuitry configured to modify an operating state of said first downforce control device, said second downforce control device, and said lift control device by sending an individual control current to each pressure reducing-relieving valve to cause each pressure reducing-relieving valve to set a pressure proportional to the associated control current.