AquaCrop model simulation under different irrigation water and nitrogen strategies
On a global scale, irrigated agriculture consumes about 72% of available freshwater resources. Deficit irrigation can be applied in the field to save irrigation water and still lead to acceptable crop production. The AquaCrop model is a simulation model for management of irrigation and nitrogen fertilizer. This model is a new model that is accurate, robust and requires fewer data inputs compared with the other models. The purpose of this study was to simulate canopy cover, grain yield and water use efficiency (WUE) for soybean using the AquaCrop model. A field line source sprinkler irrigation system was conducted under full and deficit irrigation using different nitrogen fertilizer applications during two cropping seasons for soybean at Gorgan province in Iran. The simulation results showed a reasonably accurate prediction of yield, canopy cover and WUE in all cases (error less than 23%). The simulated pattern of canopy progression over time was close to measured values, with Willmott's index of agreement for all the cases being ≥0.95 for different parameters. The AquaCrop model has the ability to simulate the WUE of soybean under different irrigation water and nitrogen applications. This model is a useful tool for managing the crop water productivity.