Water-use Zoning of major crops obtained from CROPWAT 8.0 model in the Urmia Lake basin

In this study, the water-use zoning (ETC) of wheat, barley, potato, sugar beet, onion and alfalfa crops obtained from CROPWAT 8.0 model using ArcGIS 10.3 software and data from 21 synoptic meteorological stations in the Urmia Lake basin has been at 2013-14 and 2014-15. At First, the average ETC values were estimated using climatic data, longitude and latitude, meteorological station height, soil and crop in the two years and then in the whole basin zoned and classified. Overall, the results showed that the rate of evapotranspiration was different across the basin, which indicates the effect of weather conditions in different areas of the basin on the value of evapotranspiration. Investigations also showed that the difference in water demand obtained from meteorological station data between the years under study is significant and the number of meteorological stations in the region can improve the diversity of water needs of the major crops in the region. Surveys of climatic parameters in the studied stations showed that in the areas where the highest rate of evapotranspiration was obtained, it was often with low relative humidity and higher temperature. Due to the problem of water scarcity, accurate estimation of water-use of crops in different areas can be decisive for water consumption in agriculture. Therefore, it is necessary to consider climatic differences in estimating evapotranspiration and irrigation requirement of agricultural crops for sustainable management.