In this study, the optimum irrigation depths for corn grain production under different conditions, i.e. maximum grain yield production and maximum benefit under limited land and water conditions, were determined under sprinkler irrigation in Bajgah (15 km. north of Shiraz).

 The results showed that, the optimum depth of irrigation for maximum grain yield production was 77.0 cm. Because of low price of irrigation water and sensitivity of corn crop to water deficit, the optimum depths of water were 76.8 and 73.4 cm under land and water limitations, respectively. Therefore, under limited water conditions, only 4.7 percent of the full irrigation water (maximum corn grain production) can be saved for maximum profits.