Water-saving irrigated area expansion hardly enhances crop yield while saving water under climate scenarios in China
Zhiwei Yue, La Zhuo, Xiangxiang Ji, Pengcheng Tian, Jie Gao, Wei Wang, Fubin Sun, Yiduo Duan, Pute Wu
Abstract
Facing climate change risks of water shortages and crop yield losses, it is unclear in China that whether and how irrigated area expansion and technological yield improvement can increase production with less water. Here we used 2000–2018 as the baseline and simulated the grid responses of total crop water use, production, unit water footprint by cropping modes in 2030s–2090 s in 75 scenarios with considering each 5 levels of two adaptation measures under 3 climate change pathways. Compared with climate change alone, further irrigation expansion has limited effects on increasing production (below 20.8%) and decreasing water footprint (below 3.6%). Combined two adaptation measures magnifies their respective effects, with technological yield improvement dominating contributions to production (37.0–99.6%) and water footprint (90.4–102.3%). In comprehensive optimal scenario, water footprint will reduce with increased production. No water is saved with reduced green water (1.6–1.7%) and increased blue water (6.6–21.6%). Technological advancements in yield improvement are more important for enhancing crop productivity and conserving water resources compared to an expansion of irrigated areas, as suggested by modelling simulations considering 75 scenarios in China.