virtual water flows related to grain crop trade and their influencing factors in hetao irrigation district, china

virtual water adds a new dimension to crop trades and provides a new way of thinking about water scarcity. a systematic analysis of virtual water flows requires integration of all critical drivers of virtual water flows under a single consistent framework. the aim of this study was to assess virtual water flows related to trades of grain crops (wheat, corn, rice, and coarse cereals) and their influencing factors in hetao irrigation district, china during 1981-2010. results indicated that: (1) volume of virtual water export decreased from 2.08×109 m3 in 1981 to 1.27×109 m3 in 2010. volume of virtual water import fluctuated around 621.48×106 m3 during study period; (2) cultivated area per capita and total population were the major influencing factors for virtual water export in hetao irrigation district. volume of virtual water import was mainly influenced by consumption and retail price index of grain crops. combination of large volume of virtual water export and severely constrained water resources confronted hetao irrigation district with great challenges in its sustainable development. decreasing virtual water export is a mean to alleviate regional water shortage pressure, and may be achieved by measures that constrain continued population expansion.