Estimation of Mean and Critical Irrigation Requirements for the Important Agricultural Crops of Fars Province

Irrigation requirement 15 equal to the difference between water requirement and effective rainfall. The values of water irrigation requirements were reported in NETWAT program for various crops at different regions of Iran. However, the mean values were used in that program, therefore, the values of water and irrigation requirements have probability level of 50 percent. In this study, the values of mean irrigation requirement (probability level of 50 percent) and critical irrigation requirement (high evapotranspiration and low rainfall) were predicted for most important agricultural crops in some regions of Fars province such as Abadeh, Eghlid, Darab, Dorodzan Dam, Zarghan, Shiraz, Fasa and Lar. Results showed that the reported values of irrigation requirement by NETWAT program were lower than the values of mean irrigation requirement at 88.5 percent of the cases. Also, the results indicated that the reported values of irrigation requirement by NETWAT program were lower than the values of critical irrigation requirement at 98.1 percent of conditions. Therefore, it is possible to determine the values of mean and critical irrigation requirement (high evapotranspiration and low rainfall) of important agricultural crops in Fars province.