Determining optimum applied water and seeding rates for winter wheat by using AquaCrop and mathematical‐economic analysis*
Mohammad Mehdi Moghimi, Ghazaleh Shamshiri, Ali Shabani, Ali Akbar Kamgar‐Haghighi, Mina Fateh, Mohammad Reza Mahmoudi
Abstract
Abstract The growing scarcity of water resources has made the need to optimize water consumption in the agricultural sector inevitable. In this study, the accuracy of the AquaCrop model in simulating the yield and dry matter of winter wheat under different plant densities and water levels was evaluated. Then using economic‐mathematical analysis, the optimum values of plant density and irrigation water were determined. Next, using time‐series models, the values of optimum irrigation water and economic yield were forecasted for the next 10 years. Results showed that the accuracy of the AquaCrop model to simulate grain yield and dry matter of winter wheat was very satisfactory. For seasonal rainfall of 289.9 and 394.5 mm (the values related to an occurrence probability of 50 and 80%, respectively), applying optimum irrigation water resulted in a 22.4 and 29.9% decrease in water consumption and 28.9 and 42.7% increase in land area and 47.4 and 50.2% increase in total benefit compared to full irrigation, respectively. The time‐series model used in this study was able to forecast optimum applied water with high accuracy. The forecasting results of this study can be used by farm managers and decision‐makers in water resources management in the study areas.