Temporal and spatial distribution characteristics of irrigation water requirement for main crops in the plain area of Hebei Province†

The spatial and temporal distribution of agricultural water requirement can provide a scientific basis for regional drought and disaster mitigation management and optimal allocation of irrigation water resources. The irrigation water requirement and irrigation water requirement index of the Hebei Plain during 57 years were calculated by a long series of data of 22 weather stations from 1961 to 2017, and the spatial and temporal distribution characteristics were also analysed. The results show that (a) in this long-term series, the irrigation water requirement was between 164 and 759 mm, and the irrigation water requirement index was between 0.33 and 0.78, which fluctuated between 1961 and 2017, and in 1977 began to show a downward trend; (b) irrigation water requirement and irrigation water requirement index in the Hebei Plain area had obvious seasonal changes during the year. Irrigation water requirement and irrigation water requirement index were the largest in April, the reasons for this phenomenon being high evapotranspiration and low effective precipitation; (c) the spatial distribution of irrigation water requirement and irrigation water requirement index in the Hebei Plain area are significantly different, both of which are larger in the central region and smaller in the Northeast and Southwest regions. (c) 2020 John Wiley & Sons, Ltd.