This tab is on the Water Balance Subregions dialog box.
Deficiency Scenario should be set to False if Irrigated Crop Consumptive Use (CU) is always satisfied, if shortfall, bring in external from the simulation water. --External Water
Deficiency Scenario should be set to True if Irrigated Crop Consumptive Use (CU) is reduced to water supply, if there is a water supply shortfall. --Deficit Irrigation
If not specified, Deficit Irrigation is used by default.