An agricultural machine (100, 180) applies liquid material to a field. Pulsed valve control signals control valves (109, 204) to apply the liquid material. Row pressure on the agricultural machine is sensed (127, 210) to identify when the valve is opened to apply the liquid material. Pulse characteristic sensing logic (306) receives the row pressure signal and generates a valve pulse characteristic signal. A pulsed valve control signal generator (312) generates the pulsed valve control signal based on the valve pulse characteristic signal.
