Evaluation of AquaCrop Model on Wheat Deficit Irrigation in Karaj area

Water shortage has always been the main limiting factor of agricultural development in arid and semi-arid areas. Therefore، the improvement of the water use efficiency (WUE) has high importance in these areas. The simulation models of yield response to the water are expected to play an increasingly important role in the optimization of water productivity (WP) in agriculture. The AquaCrop model، which has recently been developed by FAO، predicts crop productivity، water requirement، and water use efficiency for different scenarios including water-limiting conditions. This model requires to the evaluated for different regions and crops. In this research the potential of AquaCrop model in simulating the yield response to water availability for wheat in Karaj climate was studied. For this reason، six irrigation treatments (20، 40، 60، 80 and 100% of the water requirement and single-irrigation) were studied. Results revealed that the model performed satisfactorily in simulation of grain yield، water use efficiency in all of the irrigation treatments with irrigation intervals of 7 days، but it was less satisfactory in simulating treatments with irrigation intervals of 14 days. In addition، results showed that the model didn''t have a good performance when osmotic pressure of soil increased (when soil water content declined). However، the easiness of the AquaCrop model، the limited number of to input parameters، and the sufficient degree of simulation accuracy make it a valuable model for estimating crop productivity under different irrigation water levels conditions، supplementary and deficit irrigation، and on-farm water management strategies for improving the efficiency of water use in agriculture.