M. M. Moghimi - Department of Irrigation, College of Agriculture, Shiraz University, Shiraz, I. R. Iran
A.R. Sepaskhah - Department of Irrigation, College of Agriculture, Shiraz University, Shiraz, I. R. Iran

Abstract- In this research, the performance measures of water equity and productivity have been optimizedin the entire DoroodzanIrrigation Network by using genetic algorithms. Results indicated thatirrigation water management improvement at field scale[increasing irrigation application efficiency (Ea) and water reduction fraction (WRF)] has much more impressive impact on raising the performance measures than improvement of conveyance efficiency of channels (Ec).Increment of Ea (۴۰% to ۹۰%) andEc (۷۰% to ۹۰%)resulted inmaximumand minimumincremental effect onwater equity (on average ۴۸.۲% and ۱۷.۷%, respectively) and productivity (on average ۹۲.۰% and ۱۰%, respectively).The incremental effect of WRF (۰.۰ to ۰.۸)on water equity and productivitywas on average۳۱.۴% and ۱۰%, respectively.Furthermore, the values of performance measures decreased from wet water year to drought water year.Tape irrigation system was considered as the best choice at low quantities of WRF (<=۰.۴),however for higher values of WRF (>=۰.۶), sprinkler irrigation system was considered as the best choice for achieving higher values of water equity and productivity.Meanwhile, when equity and productivity were considered together for a specific method of deficit irrigation scheduling, under specified quantity of irrigation water, with increasing equity the water productivity reduction was negligible.

Keywords:On-farm water management, Optimization, Genetic Algorithm, water equity, water productivity