Temporal and spatial distribution of water footprint and water use efficiency of barely in different climates of Iran

The present study was conducted to provide sustainable solutions in water resources management using the concept of water footprint and water use efficiency of barley at the national level. At the beginning of the study, the provinces of the country were classified according to the Dumartin climate. Then, green, blue, gray and white water footprints in barley production and water use efficiency in different climates and provincial centers were calculated during the statistical period of 2008-2017. Also, spatial and temporal zoning of water footprint and water use efficiency were performed. The results showed that the highest water footprint of green water in the humid and Mediterranean climate of the north of the country were Rasht stations (592.553 m3/ton), Gorgan (570.86 m3/ton) and Sari (543.53 m3/ton) and the lowest In ultra-dry climate, Yazd station was obtained with 124.21 m3/ton. Zahedan station with ultra-dry climate had the highest water footprint of blue (787.01 m3/ton) and Rasht with humid climate had the lowest (86.73 m3/ton). The highest amount of gray water footprint was related to Zahedan stations (390.4 m3/ton) and Bushehr (390.11 m3/ton) and the lowest amount was in Hamedan station (239.67 m3/ton). In terms of white water footprint, the highest was in Zahedan station (1956.2 m3/ton) and the lowest was in Rasht station (515.599 m3/ton). Spatial distribution of total water footprint showed that the highest total water footprint was in the southeast of the country and the arid climate and the lowest was observed in the northern and western parts of the country. The results of water use efficiency zoning showed that the highest water use efficiency was observed in the western regions of the country and the lowest was observed in the northern and western parts of the country. Therefore, according to the obtained results, it can be said that the northern and western regions of the country are more suitable for planting barley. Also, due to the lack of water in areas with dry climate and high water footprint in these areas, barley cultivation in these areas should be avoided. In these areas, cultivation of crops with less water requirements and higher yields should be planned.