Effect of Irrigation Scheduling on Water Use Efficiency of Maize Using a Furrow Seasonal Simulation Model

Water use efficiency or the amount of dry matter production per unit of consumed water is one of the most important indices in irrigation scheduling. Accurate determination of water use efficiency¡ with taking into account various factors to better irrigation management requires the use of scientific methods and tools such as simulation model of irrigation. The aim of this study was to evaluate the effect of irrigation frequency¡ inflow rate and deficit irrigation on water use efficiency by using a seasonal simulation model to determine the best conditions to maximize water use efficiency. In order to determine the appropriate combination of design parameters such as inflow rate¡ cutoff time and irrigation frequency during the maize growing season¡ calibrated model for two different fields located in Karaj was run for different conditions and water use efficiency for each case was determined. The results showed that the highest water use efficiency for the college farm was happened in 3-day irrigation frequency and 50 percent deficit irrigation and for the Institute farm¡ the best condition was in 5-day irrigation frequency and 25 percent deficit irrigation. Using seasonal simulation models for furrow irrigation scheduling to increase water use efficiency and reduce water loss is recommended.