If you put down liquid fertilizer during planting, then you have probably burned the seedlings (at least a little bit) in the past. Placement is critical; fertilizer applied too close to the furrow can damage the sensitive roots, while fertilizer applied too far away (even by an inch) may be wasted money, as the seedlings cannot make use of it in time.
FurrowJet is a planter fertilizer attachment that allows you to dispense a starter product in the furrow, while simultaneously dispensing a nitrogen fertilizer 3/4 inch on either side of the furrow. Wings on the FurrowJet cut into the sidewall to place the fertilizer alongside the seed.
The FurrowJet operates with any liquid-application control system, so long as you use an 80-mesh filter or smaller to screen out particulates.