Adequate estimates of yields under comparable amounts of infiltrated water of different irrigation systems are essential for evaluation and adoption of irrigation decisions. A simulation model, crop evapotranspiration and Young's criteria forsubjective probability estimates from objective data were used to simulate water management regimes for pressurized and surface-irrigation systems. Historical climatic data, representative soil series and irrigation technologies for Central Arizona wereconsidered in the simulations. Comparable spatial and average yields for drip, graded furrow, level furrow and level basin systems with similar distribution uniformity of applied water were predicted when each irrigation system infiltrates to the samedepth in the low-quarter section of the irrigated field as the average of that quarter, to meet seasonal crop evapotranspiration. This implies that a similar fraction of the field (87-5%) is adequately irrigated in each case. Irrigation reuse systems areadvisable to achieve comparable, and high, water application efficiencies with furrow systems. Applied water and simulated yields were influenced by the uniformity distribution of the irrigation technologies showing that the model can be used to explorethe implications of design and management decisions. The applied water and simulated yields can be used as inputs in economic models to aid selection of farm irrigation systems.
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