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The water footprint (WF) of crop production is a user-friendly means to analyze the consumption of water resource in agricultural production systems. This study assessed the inter-annual variability of grain yield, protein yield, and their corresponding WFs and determined the major factors influencing the WFs in Saskatchewan of Canada. Both spring wheat and barley showed a significant trend of increasing grain and protein yield from 1965 to 2014, at 194.1 and 179.2 kg ha(-1) decade(-1) for grain yield (P < 0.01) and 18.6 and 17.3 kg ha(-1) decade(-1) for protein yield, respectively. Coincident with this was that both the grain yield-based and protein yield-based WFs of spring wheat and barley in Saskatchewan showed a downward trend. The grain yield-based WFs ranged from 1.08 to 1.80 m(3) kg(-1) for spring wheat, and from 0.90 to 1.38 m(3) kg(-1) for barley, whereas the protein yield-based WFs ranged from 7.93 to 10.44 m(3) kg(-1) for spring wheat and from 8.14 to 16.47 m(3) kg(-1) for barley. The grain yield-based WFs were affected by local precipitation followed by expenses on inputs from farms and the scientific and technological contributions. Under the same protein yield, the protein yield-based WFs tended to be lower in spring wheat than barley. The grain yield-based WFs of cereal crops have large potential for improvement in the future. (c) 2018 Published by Elsevier B.V.