Northward expansion of multiple cropping systems exacerbates agricultural water stress

Rising temperature promotes the expansion and shift of multiple cropping systems (CS), which increases food production while consuming more water, thereby having a disadvantage on water-scarce areas. But there exists a dearth of research on the quantitative mechanism. Here we used satellite observations combined with topography-based climate modes to analyze the spatial and temporal changes of CS in the Huang–Huai–Hai River Basin during the historical (2001–2022) and future (2050) periods, then quantified its impact on different agricultural water variables based on a grid-cellularized crop growth model. The results show that 43.86 % of the cultivated land (256.5 thousand km 2 ) exhibited an increase in CS over the past 22 years, mainly reflected in the shift from single CS to double CS in the lower reaches of the Yellow River Basin and the Huai River Basin. This change enhanced the crops’ water productivity by 11.7 % while increasing the agricultural water consumption by 15.6 % and reducing the soil water content by 7.2 %. In the future, multiple CS will further expand northward in 2050 with a maximum increasing area of 199.8 thousand km 2 , which will lead to an irrigation water deficit of 20.6 billion m 3 , approximately equivalent to 2 times the volume of water diverted along the central route of the South-to-North Water Diversion Project. Our results suggest that the planting structure of CS should be rationally arranged for food-water security under global warming especially in the northern regions. • Cropping systems of the Huang–Huai–Hai River Basin of China have increased during 2001–2022. • Multiple cropping systems will further expanded northward until 2050. • Development of multiple cropping systems raises agricultural water consumption and reduces soil water content.