1. Alizadeh, A. and A. Keshavarz. 2005. Status of Agricultural Water Use in Iran. p. 94-105. In Anonymous. (Eds.) Water Conservation, Reuse, and Recycling: Proceedings of an Iranian-American Workshop. Washington, DC. The National Academies Press. doi: 10.17226/11241., ##Anonymous, 2018. Agriculture Statistics. Volume 1: Crops. Ministry of agriculture, Planning and Economic Affairs, Office of Statistics and Information Technology. (In Persian).##Chauhan, Y., S. Allard, R. Williams, B. Williams, S. Mundree, K. Chenu and N. C. Rachaputi. 2017. Characterization of chickpea cropping systems in Australia for major abiotic production constraints. Field Crops Res. 204: 120-134.‌ ##Dehghan, H., A. Alizadeh, H. Ansari and S. A. Haghayeghi Moghaddam. 2011. Evaluation of water productivity indicators in wheat irrigated fields (Case study: Neyshabour plain). Iran. J. lrrig. Drain. 2(5): 263-275. (In Persian with English abstract).##Deihimfard, R., M. Nassiri Mahallati and A. Koocheki. 2011. SUCROSBEET: A simple model for simulating growth and development of sugar beet under potential and nitrogen-limited conditions. J. Agroecol. 2(1): 1-20. (In Persian with English Abstract).##Deihimfard, R., M. Nassiri Mahallati and A. Koocheki. 2015. Yield gap analysis in major wheat growing areas of Khorasan province, Iran, through crop modeling. Field Crops Res. 184: 28-38. ##El-Marsafawy, M. S., A. Swelam and A. Ghanem. 2018. Evolution of crop water productivity in the Nile delta over three decades (1985-2015). Water, 10(1168): 1-12.##Espe, M. B., K. G. Cassman, H. S. Yang, N. Guilpart, P. Grassini, J. Van Wart, M. Anders, D. Beighley, D. Harrell, S. Linscombe, K. McKenzie, R. Mutter, , L. T. Wilson and B. A. Linquist. 2016. Yield gap analysis of US rice production systems shows opportunities for improvement. Field Crops Res. 196: 276-283. ##FAO. 2012. World agriculture towards 2030/2050. Food and Agriculture Organization of the United Nations. Rome. Italy.##Ghasemi Nezhad Raeini, M., S. Marofi, M. Zare Kohan and A. Maleki. 2014. Investigation of water efficiency index and its comparison with the actual conditions of wheat farms. Irrig. Sci. Engin. 38(1): 71-77. (In Persian with English Abstract).##Jabro, J. D., W. B. Stevens, W. M. Iverson, R. G. Evans and B. L. Allen. 2014. Crop water productivity of sugar beet as affected by tillage. Agron. J. 106: 2280-2286.##Keshavarz, A. and H. Dehghani Sanij. 2011. Water productivity index and solutions for future agricultural activities in Iran. Economic Strategy. 1(1): 199-233. (In Persian with English abstract).##Mandare A. B., S. K. Ambast, N. K. Tyagi and J. Singh. 2008. On-farm water management in saline groundwater area under scarce canal water supply condition in the Northwest India. Agric. Water Manage. 95: 516-526.##Molden, D., T. Oweis, P. Steduto, P. Bindraban, M. A. Hanjra and J. Kijne. 2010. Improving agricultural water productivity: between optimism and caution. Agric. Water Manage. 97(4): 528-535.##Qiu, G. Y., L. M. Wang, X. H. He, X. Y. Zhang, S. Y. Chen, J. Chen and Y. H. Yang. 2008. Water use efficiency and evapotranspiration of winter wheat and its response to irrigation regime in the north China plain. Agric. Forest Meteorol.148: 1848-1859.##Rahnama, M. R. and L. Shaddel. 2015. Evaluation of sustainability and the optimal population based on water resources in Mashhad. Geography Urban Plan. Res. 3(2): 123-143 (In Persian with English abstract).##Sahin, U., S. Ors, F. M. Kiziloglu and Y. Kuslu. 2014. Evaluation of water use and yield responses of drip-irrigated sugar beet with different irrigation techniques. Chilean J. Agric. Res. 74 (3): 302-310.##Saini, K. S. and N. S. Brar. 2018. Crop and water productivity of sugar beet (Beta vulgaris) under different planting methods and irrigation schedules. Agric. Res. 7(1): 93-97.‌##Saxton, K. E. and P. H. Willey. 2006. The SPAW Model for Agricultural Field and Pond Hydrologic Simulation. In: Singh, V. P. and D. Frevert. (Eds.) Watershed Models. CRC Press, Taylor and Francis Group, LLC, pp. 400-435. ##Spitters, C. J. T. H. Van Keulen and D. W. G. Van Kraalingen. 1989. A Simple and Universal Crop Growth Simulator: SUCROS87. In: Rabbinge et al. (Eds.) Simulation and Systems Management in Crop Protection. Simulation Monograph, vol. 32. Pudoc, Wageningen. The Netherlands, pp. 147-181.##Tatari, M. 2008. Dryland wheat yield prediction using climatic and edaphic data by applying neural networks. PhD Dissertation. Ferdowsi University of Mashhad, Mashhad, Iran. (In Persian with English abstract). ##Van Ittersum, M. K., K. G. Cassman, P. Grassini, J. Wolf, P. Tittonell and Z. Hochman. 2013. Yield gap analysis with local to global relevance- A review. Field Crops Res. 143: 4-17. ##Van Laar, H. H., J. Goudriaan and H. Van Keulen. 1997. SUCROS97: Simulation of Crop Growth for Potential and Water-limited Production Situations. Quantitative Approaches in Systems Analysis, No. 14. C.T. de Wit Graduate School for Production Ecology and Resource Conservation, Wageningen, The Netherlands.##Vazifedoust, M., J. C. Van Dam, R. A. Feddes and M. Feizi. 2008. Increasing water productivity of irrigated crops under limited water supply at field scale. Agric. Water Manage. 95: 89-102.##Wang, J., E. Wang, H. Yin, L. Feng and J. Zhang. 2014. Declining yield potential and shrinking yield gaps of maize in the North China Plain. Agric. Forest Meteorol. 195: 89-101.##