Don't allow the water to discharge from the well. Do this at least four times. For deep well turbine pumps with electric motors, allow five minutes between starts to allow the water to flow back into the well. Force the chlorine into the aquifer by pouring in at least 100 gallons of water. Let the chlorine stand in the well for 24 hours.
Chlorine needs time to kill iron bacteria.
Surge the well at least twice more then pump the water to waste. This water can be pumped through the irrigation system. In fact it will help clean out pipelines and spray nozzles. Stand upwind because the chlorine smell could be strong. Pump until the odor of chlorine is gone.