**9. Conclusions**

The AquaCrop model with a salinity module was used to evaluate the agronomic performance of two barley varieties for the three different agro-climatic zones in Tunisia. These zones represent sub-humid, semi-arid, and arid climates. The model was calibrated and evaluated using field data from two years (2012 and 2014). The excellent correlation between the simulated and measured data of biomass, yield, and soil salinity confirms the ability of AquaCrop model to simulate crop growth under different climatic conditions. The scenario results using the calibrated model indicate that farmers with higher salinity water for irrigation should grow tolerant barley genotypes. However, from a sustainability point of view, irrigation amounts should be kept to a minimum to optimize crop yields instead of targeting potential yields.

**Author Contributions:** Conceptualization, Z.H.; Data curation, F.E.B.A. and S.A.; Formal analysis, Z.H.; Methodology, Z.H., A.S. and Z.C.; Supervision, Y.T.; Writing—Original draft, Z.H.; Writing—Review and editing, A.S.Q. and A.G. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was supported by the Laboratory of Genetics and Cereal Breeding, National Agronomic Institute of Tunisia, Carthage University, and International Center for Biosaline Agriculture (ICBA). And The APC was funded by ICBA.

**Conflicts of Interest:** The authors declare no conflict of interest.
