Comparison and evaluation of blue, green and gray water footprint of wheat in different climates of Iran

Water footprint index shows actual consumption of water in three parts: Blue, green and gray. Today, the water footprint has been taken into account in the modern management of water resources with an integrated approach. In this research, wheat water footprint was evaluated at strategic points in terms of water resources (blue water, green water and gray water) and an optimal cropping pattern in different climates of Iran. For this purpose, 33 provinces of the country were first classified according to the UNESCO cluster. All stations were classified in 6 climates; Plentiful Humidity Cool Warm (PH-C-W), Semi -Arid Cold Warm (SA-K-W), Semi -Arid Cool Very Warm (SA-C-VW), Arid Cool Warm (A-C-W), Arid Mild Warm (A-M-W), Arid Cool Very Warm (A-C-VW). Then the water footprint was calculated and evaluated in each climate and all three component, including blue, green and gray water. The results showed that the highest amounts of blue water footprint are seen in the central and southern parts of Iran, the highest amounts of green water footprint in in the northern and western parts as well as the highest amount of gray water footprint in the southern parts of the country can be seen. The average of footprints for green, blue and gray was obtained 503.3, 1392.8 and 286.2of 34 m3/ton in the country. The results of this study showed that wheat crop cultivation was not suitable in all climates and was not recommended in A-C-W and A-C-VW regions of Iran.