Impact of future climate change on regional crop water requirement-A case study of Hetao irrigation district, China

Abstract

Water shortage is a limiting factor for agricultural production in China, and climate change will affect agricultural water use. Studying the effects of climate change on crop irrigation requirement (CIR) would help to tackle climate change, from both food security and sustainable water resource use perspectives. This paper applied SDSM (Statistical DownScaling Model) to simulate future meteorological parameters in the Hetao irrigation district (HID) in the time periods 2041-2070 and 2071-2099, and used the Penman-Monteith equation to calculate reference crop evapotranspiration (ET0), which was further used to calculate crop evapotranspiration (ETc) and crop water requirement (CWR). CWR and predicted future precipitation were used to calculate CIR. The results show that the climate in the HID will become warmer and wetter; ET0 would would increase by 4% to 7%; ETc and CWR have the same trend as ET0, but different crops have different increase rates. CIR would increase because of the coefficient of the increase of CWR and the decrease of effective precipitation. Based on the current growing area, the CIR would increase by 198 × 106 to 242 × 106 m3 by the year 2041-2070, and by 342 × 106 to 456 × 106 m3 by the years 2071-2099 respectively. Future climate change will bring greater challenges to regional agricultural water use.