Irrigation amounts can be either fixed amounts (IRRAMT, irri.100) or automatically set (AUIRRI, irri.100) according to the soil moisture status. Automatic irrigations are scheduled if the available water stored in the plant root zone falls below a nominated fraction of the available water holding capacity (FAWHC, irri.100). The amount of water applied by the automatic option allows for the addition of a nominated amount of water (IRRAUT, irri.100) or for irrigation up to field capacity or up to field capacity plus an allowance for potential evapotranspiration.