A microcomputer model is developed for use as a planning tool to aid i
n the sequence of development, evaluation and selection of the best al
ternative on-farm irrigation system plan. The model is used to predict
operation of an on-farm irrigation system under given site-specific c
onditions and select the best system plan from a wt of alternatives. T
he best system plan is selected based on maximization of annualized ne
t returns to land and management. Application of the model to a case s
tudy is presented. The consequences of limitations in water, energy an
d labor use and/or different economic scenarios are evaluated as it co
ncerns system plan selection.