2.3.3. AquaCrop Model Calibration and Validation

Before using the AquaCrop crop model to simulate grain yields of a local durum wheat cultivar called "Mexicali" in the future horizon 2035–2064 (under RCP 4.5 and RCP 8.5). This crop model was first calibrated using Mexicali cultivar phenological data, observed

by [37] at a field test during the 2010/2011 agricultural campaign at the experimental farm of Sétif (belonging to the National Institute of Agronomic Research). This farm is located at 36.15◦ N latitude and 5.37◦ E longitude, and at an altitude of 970 m. In order to calibrate AquaCrop, according to the climatological conditions of this above Setif experimental site, the daily climate data (Tmax, Tmin and P) observed during the growing season 2010/2011, the daily ET0 data throughout this growing season, calculated using ET0 calculator, and also the soil data (PWP, FC, SAT and soil horizon deeps) are injected into this model.

The durum wheat's non-conservative parameters in the AquaCrop model are given in Table 2, such as: the sowing density, the length (in days) of the stages of emergence, maximum leaf expansion, maximum roots depth, flowering, seed formation, and the maturity observed during the (2010/2011) growing season, are also introduced into the AquaCrop model. Then, the last was validated with the values of the Mexicali cultivar's final grain yields and above-ground biomass, observed throughout the experimentations, carried out by [37], during the period of the three growing seasons: (2010/2011), (2011/2012) and (2012/2013), at the Setif experimental farm.

**Table 2.** Calibrated AquaCrop model specific parameters for Mexicali cultivar of wheat.


GDD, growing degree-day; SWDT, soil water depletion threshold; TASW, total available soil water.

Finally, the values of the Mexicali cultivar's non-conservative parameters in AquaCrop are calibrated several times in order to obtain values of simulated Mexicali cultivargrain yield and final above-ground biomass, close to those observed by [37] during these above three experimentation growing seasons. Thus, the final values of the Mexicali cultivar's non-conservative (indicated in Table 2) and conservative parameters are applied in all simulation scenarios on AquaCrop.
